In June 2020, Hornady introduced the 6mm ARC, a new SAAMI cartridge optimized for AR-platform rifles*. The new 6mm ARC is basically a 6.5 Grendel necked down to 6mm, with the shoulder moved back around .030″. That pushed-back shoulder does reduce case capacity (and velocity), but we assume Hornady did that to create a shorter, proprietary chamber so people could not simply neck-down Lapua 6.5 Grendel brass, as has been done for years with Robert Whitley’s outstanding 6mm AR wildcat.

CLICK Image for official SAAMI Specifications:

If you are intrigued by the 6mm ARC, you’ll find the products you need at Brownells — barrels, bolts, mags and even complete 6mm ARC Rifles. Midsouth has 6mm ARC ammo and reloading dies. For general information, see 6mm ARC Wikipedia Info Page.

What Is the 6mm ARC Cartridge?
The 6mm ARC cartridge is a new SAAMI-spec cartridge based on the 6.5 Grendel case necked down for 6mm bullets, with the shoulder moved back 0.030. Yes it is designed to run in AR15-platform rifles. You’ll need a new barrel, bolt, and mags. If you already have an AR chambered in 6.5 Grendel, the ONLY thing you need to change is the barrel. Everything else — bolt, magazines, gas system – is compatible with 6mm ARC.

▶ Official SAAMI Cartridge (not wildcat)
▶ Fits standard AR15-platform rifles
▶ Fits Short/Mini action bolt rifles
▶ Efficient short, fat case design
▶ 30-degree case shoulder

For more INFO, see 6mm ARC Info Page.

What Do I Need To Shoot the 6mm ARC?
Faxon and Ballistic Advantage are already producing barrels, with more manufacturers sure to follow. All the other required components are already on the market for 6.5 Grendel rifles. Aero Precision already offers complete 6mm ARC uppers.

If you’re converting a standard 5.56×45 mm (.223 Rem) AR15 upper to shoot 6mm ARC, you’ll need a 6mm barrel, a Type II 6.5 Grendel bolt carrier group, and new magazines. Some folks have suggested standard AR mags will work, but trust us, you want the magazines that have been designed for 6.5 Grendel. Most of the hardware you need is available at Brownells.

6mm ARC Videos from Hornady (18 Total)

* While 6-6.5 Grendel shooters are known to run stout pressures, the new 6mm ARC cartridge has a relatively moderate Maximum Average Pressure (MAP) rating of 52,000 psi according to the official SAAMI specifications. For a variety of reasons, is wise to keep pressures in a semi-auto rifle moderate. Don’t chase the velocities you might get in a bolt-action gun.

CLICK HERE for Sierra Bullets 6.5 Grendel LOAD DATA PDF »

Sierra Bullets has released load data for the 6.5 Grendel, a popular cartridge that works equally well in bolt guns and AR15-platform gas guns. Sierra published comprehensive 6.5 Grendel load data, covering 19 powders and eight (8) different bullets from 85 to 130 grains. NOTE: Hornady-brand brass (see below) was used for Sierra’s 6.5 Grendel tests, not the stronger Lapua 6.5 Grendel brass. Hand-loaders using Lapua 6.5 Grendel brass may need to adjust their loads. Also Winchester WSR primers were used. We imagine most precision hand-loaders will prefer CCI or Federal primers.

In developing its 6.5 Grendel load data, Sierra tested a very wide selection of propellants, 19 in all. For the 85gr to 100gr varmint bullets, modern powders such as XMR 2230, Power Pro Varmint, and Ramshot TAC offered the best velocity in the 24″ test barrel. For the heavier 120gr to 130gr match bullets, Sierra tested a selection of powders. Highest velocities came with Power Pro Varmint and TAC. If you’re looking for best accuracy, consider the slower burn-rate powders such as IMR 8208 XBR and Varget — but you’ll sacrifice some speed. Overall, Sierra’s latest 6.5 Grendel load data is an excellent addition to the 6.5 Grendel knowledge base. Thanks Sierra!

Here are Sierra’s 6.5 Grendel Load Data Charts for Sierra’s 123gr HPBT, 130gr HPBT, and 130gr TMK. There are a five other tables for lighter-weight Sierra bullets.

History of the 6.5 Grendel Cartridge
The 6.5 Grendel originated as a 6mm PPC necked up to 6.5 mm. After Alexander Arms relinquished the “6.5 Grendel” Trademark, the 6.5 Grendel was standardized as an official SAAMI cartridge. It has become popular with target shooters and hunters alike because it is accurate, efficient, and offers modest recoil. Good for small to medium game, the 6.5 Grendel is available in lightweight hunting rifles, such as the Howa Mini Action Rifle. And the 6.5 Grendel is one of the most accurate cartridges suitable for modern AR-15 platform rifles.

CLICK HERE for 6.5 Grendel Cartridge History (Wikipedia entry).

In June 2020, Hornady introduced the 6mm ARC, a new SAAMI cartridge optimized for AR-platform rifles*. The new 6mm ARC is basically a 6.5 Grendel necked down to 6mm, with the shoulder moved back around .030″. That pushed-back shoulder does reduce case capacity (and velocity), but we assume Hornady did that to create a shorter, proprietary chamber so people could not simply neck-down Lapua 6.5 Grendel brass, as has been done for years with Robert Whitley’s outstanding 6mm AR wildcat.

CLICK Image for official SAAMI Specifications:

If you are intrigued by the 6mm ARC, you’ll find the products you need at Brownells — barrels, bolts, mags and even complete 6mm ARC Rifles. Midsouth has 6mm ARC ammo and reloading dies. For general information, see 6mm ARC Wikipedia Info Page.

What Is the 6mm ARC Cartridge?
The 6mm ARC cartridge is a new SAAMI-spec cartridge based on the 6.5 Grendel case necked down for 6mm bullets, with the shoulder moved back 0.030. Yes it is designed to run in AR15-platform rifles. You’ll need a new barrel, bolt, and mags. If you already have an AR chambered in 6.5 Grendel, the ONLY thing you need to change is the barrel. Everything else — bolt, magazines, gas system – is compatible with 6mm ARC.

▶ Official SAAMI Cartridge (not wildcat)
▶ Fits standard AR15-platform rifles
▶ Fits Short/Mini action bolt rifles
▶ Efficient short, fat case design
▶ 30-degree case shoulder

For more INFO, see 6mm ARC Info Page.

What Do I Need To Shoot the 6mm ARC?
Faxon and Ballistic Advantage are already producing barrels, with more manufacturers sure to follow. All the other required components are already on the market for 6.5 Grendel rifles. Aero Precision already offers complete 6mm ARC uppers.

If you’re converting a standard 5.56×45 mm (.223 Rem) AR15 upper to shoot 6mm ARC, you’ll need a 6mm barrel, a Type II 6.5 Grendel bolt carrier group, and new magazines. Some folks have suggested standard AR mags will work, but trust us, you want the magazines that have been designed for 6.5 Grendel. Most of the hardware you need is available at Brownells.

6mm ARC Videos from Hornady (18 Total)

* While 6-6.5 Grendel shooters are known to run stout pressures, the new 6mm ARC cartridge has a relatively moderate Maximum Average Pressure (MAP) rating of 52,000 psi according to the official SAAMI specifications. For a variety of reasons, is wise to keep pressures in a semi-auto rifle moderate. Don’t chase the velocities you might get in a bolt-action gun.

Instead of using the standard .223 Remington or 5.56x45mm NATO round, you have many options for an AR-15, as shown above. This photo is from Complete Guide to Alternative AR-15 Rounds in the 80% Arms Blog. Some of the most notable alternative chamberings for AR-15s are:

20 Practical — Simply the .223 Rem necked down to .204 caliber. Requires new barrel. Same bolt, same magazines. Best Bang for the Buck.
6mm ARC — The 6mm ARC (from Hornady), is a SAAMI cartridge optimized for AR-platform rifles. The 6mm ARC is basically a 6.5 Grendel necked down to 6mm, with the shoulder moved back around .030″.
6.5 Grendel — Moderately expensive, 6.5 Grendel requires a new barrel, bolt, and magazines. Most use the 6.5 Grendel for competitive shooting and/or hunting.
.300 Blackout — Moderately expensive, the .300 Blackout requires a barrel change. This is used for home defense, and hunting. WARNING — with some bullets this round can be chambered in a .223 Rem barrel, with disastrous consequences.
.50 Beowulf — The most expensive alternative AR-15 cartridge, this requires new barrel and bolt. The .50 Beowulf was created for game hunting, but most hunters use something more practical.

Of these five options, our top choice is the 20 Practical, followed by the 6.5 Grendel. Check out our featured 20 Practical AR Rifle Report. This 20 Practical cartridge is highly effective on small varmints, and has shown outstanding accuracy in AR-platform rifles crafted by Robert Whitley.

20 Practical — High-Velocity, Affordable Alternative

The 20 Practical is simply a .223 Remington necked down to .204 caliber. This efficient little cartridge can launch 32-grainers at over 4200 fps, with impressive results on P-Dogs. This makes the 20 Practical a great choice for an AR-based varmint rifle.

20 Practical Ultimate Varminter
Many years back, as a “proof-of-concept”, AccurateShooter.com created a 20 Practical AR15 Ultimate Varminter with a custom 20-caliber upper from Robert Whitley of AR-X Enterprises, LLC. That project rifle was ultra-accurate — every 5-shot group out of the gun was less than the size of a dime. The 20 Practical cartridge is simply the .223 Rem necked down to 20 caliber — you can use standard .223 brass and load with standard .223 Rem dies. Just swap in a smaller expander and use smaller neck bushings.

20 Practical in AR15 Demonstration Video

6mm ARC — Popular New SAAMI Cartridge Promoted by Hornady

The 6mm ARC is basically a 6.5 Grendel necked down to 6mm, with the shoulder moved back around .030″. That pushed-back shoulder does reduce case capacity (and velocity), but we assume Hornady did that to create a shorter, proprietary chamber so people could not simply neck-down Lapua 6.5 Grendel brass, as has been done for years with Robert Whitley’s outstanding 6mm AR wildcat.

CLICK Image for official SAAMI Specifications:

If you are intrigued by the 6mm ARC, you’ll find the products you need at Brownells — uppers, barrels, bolts, and magazines. Brownells also sells Hornady-made 6mm ARC factory-loaded ammo but most is out-of-stock currently. MidwayUSA currently has Hornady 108gr ELD Match 6mm ARC ammo in stock.

What Is the 6mm ARC Cartridge?
The 6mm ARC cartridge is a modern SAAMI-spec cartridge based on the 6.5 Grendel case necked down for 6mm bullets, with the shoulder moved back 0.030. Yes it is designed to run in AR15-platform rifles. You’ll need a new barrel, bolt, and mags. If you already have an AR chambered in 6.5 Grendel, the ONLY thing you need to change is the barrel. Everything else — bolt, magazines, gas system – is compatible with 6mm ARC.

▶ Official SAAMI Cartridge (not wildcat)
▶ Fits standard AR15-platform rifles
▶ Fits Short/Mini action bolt rifles
▶ Efficient short, fat case design
▶ 30-degree case shoulder

What Do I Need To Shoot the 6mm ARC?
Faxon and Ballistic Advantage are already producing barrels, with more manufacturers sure to follow. All the other required components are already on the market for 6.5 Grendel rifles. Aero Precision already offers complete 6mm ARC uppers.

If you’re converting a standard 5.56×45 mm (.223 Rem) AR15 upper to shoot 6mm ARC, you’ll need a 6mm barrel, a Type II 6.5 Grendel bolt carrier group, and new magazines. Some folks have suggested standard AR mags will work, but trust us, you want magazines designed for 6.5 Grendel.

While 6-6.5 Grendel shooters are known to run stout pressures, the 6mm ARC cartridge has a relatively moderate Maximum Average Pressure (MAP) rating of 52,000 psi according to the official SAAMI specifications. For a variety of reasons, is wise to keep pressures in a semi-auto rifle moderate. Don’t chase the velocities you might get in a bolt-action gun.

The 6.5 Grendel — Accurate, Plus Good for Hunters

The 6.5 Grendel round is one of the most accurate cartridges for the AR-15 platform. The 6.5 Grendel round offers a larger-diameter, .264-caliber (6.5mm) bullet running at good velocities. This provides ample energy for smaller game and deer. The 6.5 Grendel is often used for hunting deer up to 300 yards.

History of the 6.5 Grendel Cartridge
The 6.5 Grendel originated as a 6mm PPC necked up to 6.5 mm. After Alexander Arms relinquished the “6.5 Grendel” Trademark, the 6.5 Grendel was standardized as an official SAAMI cartridge. It has become popular with target shooters and hunters alike because it is accurate, efficient, and offers modest recoil. Good for small to medium game, the 6.5 Grendel is becoming a popular chambering in lightweight hunting rifles, such as the Howa 1500 Youth Model.

The .300 Blackout — Risky Business

The .300 Blackout appeals to folks who want a .30-caliber defense round. This can be loaded at various velocities. Loaded at subsonic speeds and shot with a suppressor, the .300 BLK offers very low sound levels. Unfortunately, that .300 Blackout cartridge can fit in a .223 Rem chamber. Shooting a .308-caliber bullet in .223 bore is a recipe for disaster.

The .300 AAC Blackout aka “300 BLK”, is a compact 30-caliber cartridge designed to work in AR-15 rifles. It has a shorter cartridge case to accommodate the bigger 30-caliber bullet while still fitting in a standard AR-15 magazine. Unfortunately, that’s the danger. A careless shooter can toss a .300 Blackout cartridge in with .223 Rem rounds without noting. And because the case-head size is the same as the .223 Rem (5.56×45) the rifle’s bolt assembly will happily chamber and fire the .300 BLK round. Problem is, that forces a .308 diameter bullet down an undersized .223-caliber bore. Not good!

This images were provided by Tactical Rifle Shooters on Facebook. The message was clear: “Don’t try to run 300 Blackout in your .223/5.56mm. It won’t end well. The problem is identical rifles and identical magazines but different calibers.”

Image from Accurate Shooter Forum. Cutaway shows the jammed .30-Cal bullet:

For those who MUST have a .300 Blackout, here are some things you can do:

1. Use different colored magazines for .300 Blackout vs. .223 Remington.
2. Mark .223 Rem upper handguards with the caliber in bright paint.
2. Fit all your uppers with caliber-labeled ejection port covers.
4. Mark all .300 BLK Rounds with heavy black marker.

In June 2020, Hornady introduced the 6mm ARC, a new SAAMI cartridge optimized for AR-platform rifles*. The new 6mm ARC is basically a 6.5 Grendel necked down to 6mm, with the shoulder moved back around .030″. That pushed-back shoulder does reduce case capacity (and velocity), but we assume Hornady did that to create a shorter, proprietary chamber so people could not simply neck-down Lapua 6.5 Grendel brass, as has been done for years with Robert Whitley’s outstanding 6mm AR wildcat.

CLICK Image for official SAAMI Specifications:

If you are intrigued by the 6mm ARC, you’ll find the products you need at Brownells — barrels, bolts, mags and even complete 6mm ARC Rifles. Midsouth has 6mm ARC ammo and reloading dies. For general information, see 6mm ARC Wikipedia Info Page.

What Is the 6mm ARC Cartridge?
The 6mm ARC cartridge is a new SAAMI-spec cartridge based on the 6.5 Grendel case necked down for 6mm bullets, with the shoulder moved back 0.030. Yes it is designed to run in AR15-platform rifles. You’ll need a new barrel, bolt, and mags. If you already have an AR chambered in 6.5 Grendel, the ONLY thing you need to change is the barrel. Everything else — bolt, magazines, gas system – is compatible with 6mm ARC.

▶ Official SAAMI Cartridge (not wildcat)
▶ Fits standard AR15-platform rifles
▶ Fits Short/Mini action bolt rifles
▶ Efficient short, fat case design
▶ 30-degree case shoulder

For more INFO, see 6mm ARC Info Page.

What Do I Need To Shoot the 6mm ARC?
Faxon and Ballistic Advantage are already producing barrels, with more manufacturers sure to follow. All the other required components are already on the market for 6.5 Grendel rifles. Aero Precision already offers complete 6mm ARC uppers.

If you’re converting a standard 5.56×45 mm (.223 Rem) AR15 upper to shoot 6mm ARC, you’ll need a 6mm barrel, a Type II 6.5 Grendel bolt carrier group, and new magazines. Some folks have suggested standard AR mags will work, but trust us, you want the magazines that have been designed for 6.5 Grendel. Most of the hardware you need is available at Brownells.

6mm ARC Videos from Hornady (18 Total)

* While 6-6.5 Grendel shooters are known to run stout pressures, the new 6mm ARC cartridge has a relatively moderate Maximum Average Pressure (MAP) rating of 52,000 psi according to the official SAAMI specifications. For a variety of reasons, is wise to keep pressures in a semi-auto rifle moderate. Don’t chase the velocities you might get in a bolt-action gun.

CLICK HERE for Sierra Bullets 6.5 Grendel LOAD DATA PDF »

Sierra Bullets has released load data for the 6.5 Grendel, a popular cartridge that works equally well in bolt guns and AR15-platform gas guns. Sierra published comprehensive 6.5 Grendel load data, covering 19 powders and eight (8) different bullets from 85 to 130 grains. NOTE: Hornady-brand brass (see below) was used for Sierra’s 6.5 Grendel tests, not the stronger Lapua 6.5 Grendel brass. Hand-loaders using Lapua 6.5 Grendel brass may need to adjust their loads. Also Winchester WSR primers were used. We imagine most precision hand-loaders will prefer CCI or Federal primers.

In developing its 6.5 Grendel load data, Sierra tested a very wide selection of propellants, 19 in all. For the 85gr to 100gr varmint bullets, modern powders such as XMR 2230, Power Pro Varmint, and Ramshot TAC offered the best velocity in the 24″ test barrel. For the heavier 120gr to 130gr match bullets, Sierra tested a selection of powders. Highest velocities came with Power Pro Varmint and TAC. If you’re looking for best accuracy, consider the slower burn-rate powders such as IMR 8208 XBR and Varget — but you’ll sacrifice some speed. Overall, Sierra’s latest 6.5 Grendel load data is an excellent addition to the 6.5 Grendel knowledge base. Thanks Sierra!

Here are Sierra’s 6.5 Grendel Load Data Charts for Sierra’s 123gr HPBT, 130gr HPBT, and 130gr TMK. There are a five other tables for lighter-weight Sierra bullets.

History of the 6.5 Grendel Cartridge
The 6.5 Grendel originated as a 6mm PPC necked up to 6.5 mm. After Alexander Arms relinquished the “6.5 Grendel” Trademark, the 6.5 Grendel was standardized as an official SAAMI cartridge. It has become popular with target shooters and hunters alike because it is accurate, efficient, and offers modest recoil. Good for small to medium game, the 6.5 Grendel is available in lightweight hunting rifles, such as the Howa Mini Action Rifle. And the 6.5 Grendel is one of the most accurate cartridges suitable for modern AR-15 platform rifles.

CLICK HERE for 6.5 Grendel Cartridge History (Wikipedia entry).

Instead of using the standard .223 Remington or 5.56x45mm NATO round, you have many options for an AR-15. Dozens of cartridge variants have been tried in AR-15s. Some of the most noteworthy and popular alternative chamberings for AR-15s are:

20 Practical — This is simply the .223 Rem necked down to .204 caliber. Requires new barrel. Same bolt, same magazines. Best bang for the buck.
.224 Valkyrie — A necked-down version of the 6.8 SPC, the .224 Valkyrie was introduced by Federal a few seasons back. It has better ballistics than the .223 Remington, if used with a suitable barrel.
6mm ARC — Relatively new cartridge that works well for varminting, self-defense, tactical competitions, and deer hunting. Good selection of bullets and factory-loaded ammunition.
6.5 Grendel — Accurate and proven across the course, the 6.5 Grendel requires a new barrel, bolt, and magazines. Most use the 6.5 Grendel for competitive shooting and/or hunting.
.300 Blackout — Moderately expensive, the .300 Blackout requires a barrel change. This is used for home defense, and hunting. WARNING — with some bullets this round can be chambered in a .223 Rem barrel, with disastrous consequences.
.458 SOCOM — Pretty expensive, requires new barrel and bolt. The .458 SOCOM round is typically used for hunting though it was originally designed for Close Quarters Battle (CQB).

Of these six options, our favorite is the 20 Practical, followed by the 6mm ARC and 6.5 Grendel. The 20 Practical is a great varminting round. Check out our featured 20 Practical AR Rifle Report. This 20 Practical cartridge is highly effective on small varmints, and has shown outstanding accuracy in AR-platform rifles crafted by Robert Whitley.

20 Practical — High-Velocity, Affordable Alternative

The 20 Practical is simply a .223 Remington necked down to .204 caliber. This efficient little cartridge can launch 32-grainers at over 4200 fps, with impressive results on P-Dogs. This makes the 20 Practical a great choice for an AR-based varmint rifle.

20 Practical Ultimate Varminter
A decade ago, as a “proof-of-concept”, AccurateShooter.com created a 20 Practical AR15 Ultimate Varminter with a custom 20-caliber upper from Robert Whitley of AR-X Enterprises, LLC. That project rifle was ultra-accurate — every 5-shot group out of the gun was less than the size of a dime. That gun was auctioned off, but Robert Whitley continues to produce custom 20 Practical AR15 uppers. (The 20 Practical cartridge is simply the .223 Rem necked down to 20 caliber — you can use standard .223 brass and load with standard .223 Rem dies. Just swap in a smaller expander and use smaller neck bushings.)

6mm ARC — Popular New SAAMI Cartridge Promoted by Hornady

In June 2020, Hornady introduced the 6mm ARC, a new SAAMI cartridge optimized for AR-platform rifles*. The new 6mm ARC is basically a 6.5 Grendel necked down to 6mm, with the shoulder moved back around .030″. That pushed-back shoulder does reduce case capacity (and velocity), but we assume Hornady did that to create a shorter, proprietary chamber so people could not simply neck-down Lapua 6.5 Grendel brass, as has been done for years with Robert Whitley’s outstanding 6mm AR wildcat.

CLICK Image for official SAAMI Specifications:

If you are intrigued by the 6mm ARC, you’ll find the products you need at Brownells — uppers, barrels, bolts, and magazines. Brownells also sells Hornady-made 6mm ARC factory-loaded ammo but most is out-of-stock currently. MidwayUSA currently has Hornady 108gr ELD Match 6mm ARC ammo in stock. For general information, see 6mm ARC Info Page.

What Is the 6mm ARC Cartridge?
The 6mm ARC cartridge is a modern SAAMI-spec cartridge based on the 6.5 Grendel case necked down for 6mm bullets, with the shoulder moved back 0.030. Yes it is designed to run in AR15-platform rifles. You’ll need a new barrel, bolt, and mags. If you already have an AR chambered in 6.5 Grendel, the ONLY thing you need to change is the barrel. Everything else — bolt, magazines, gas system – is compatible with 6mm ARC.

▶ Official SAAMI Cartridge (not wildcat)
▶ Fits standard AR15-platform rifles
▶ Fits Short/Mini action bolt rifles
▶ Efficient short, fat case design
▶ 30-degree case shoulder

For more INFO, see 6mm ARC Info Page.

What Do I Need To Shoot the 6mm ARC?
Faxon and Ballistic Advantage are already producing barrels, with more manufacturers sure to follow. All the other required components are already on the market for 6.5 Grendel rifles. Aero Precision already offers complete 6mm ARC uppers.

If you’re converting a standard 5.56×45 mm (.223 Rem) AR15 upper to shoot 6mm ARC, you’ll need a 6mm barrel, a Type II 6.5 Grendel bolt carrier group, and new magazines. Some folks have suggested standard AR mags will work, but trust us, you want the magazines that have been designed for 6.5 Grendel. All the hardware you need is currently available at Brownells.

While 6-6.5 Grendel shooters are known to run stout pressures, the new 6mm ARC cartridge has a relatively moderate Maximum Average Pressure (MAP) rating of 52,000 psi according to the official SAAMI specifications. For a variety of reasons, is wise to keep pressures in a semi-auto rifle moderate. Don’t chase the velocities you might get in a bolt-action gun.

The 6.5 Grendel — Accurate, Plus Good for Hunters

The 6.5 Grendel round is one of the most accurate cartridges for the AR-15 platform. The 6.5 Grendel round offers a larger-diameter, .264-caliber (6.5mm) bullet running at good velocities. This provides ample energy for smaller game and deer. The 6.5 Grendel is often used for hunting deer up to 300 yards.

History of the 6.5 Grendel Cartridge
The 6.5 Grendel originated as a 6mm PPC necked up to 6.5 mm. After Alexander Arms relinquished the “6.5 Grendel” Trademark, the 6.5 Grendel was standardized as an official SAAMI cartridge. It has become popular with target shooters and hunters alike because it is accurate, efficient, and offers modest recoil. Good for small to medium game, the 6.5 Grendel has been offered in lightweight hunting rifles, such as the Howa 1500 Mini Action.

.224 Valkyrie Cartridge — Impressive with Heavy .22-Cal Bullets

The new .224 Valkyrie was introduced in 2019 as a Hot Rod cartridge that will work in AR15s. Basically a 6.8 SPC necked down to .22 caliber, the Valkyrie has a shorter case than the .223 Remington (and 5.56×45 NATO). This allows you to load the longest, heaviest .224-caliber bullets and still feed reliably from an AR15-type magazine. Designed to rival the .22 Nosler while still running well in ARs, the .224 Valkyrie offers excellent long-range performance when loaded with modern, high-BC bullets. We expect some bolt-action PRS shooters might adopt the .224 Valkyrie. Why? Reduced recoil. With the 90gr SMK, the .224 Valkyrie offers ballistics similar to the 6.5 Creedmoor but with significantly less felt recoil. It can also be a viable alternative to a .22-250 for varminters using an AR platform.

Image from Social Regressive .224 Valkyrie Youtube Video.

Our friend Gavin Gear of UltimateReloader.com found a superbly accurate load with Berger 80.5gr bullets. Watch this video to learn more:

Sierra Bullets has published extensive load data for the .224 Valkyrie. This covers over a dozen powder types — many more than the Hodgdon database. Sierra’s .224 Valkyrie load data covers projectiles from 50 grain all the way up to 95 grains. With the 90 to 95 grain bullets, the little Valkyrie can give 6mm match cartridges a real run for their money — offering similar ballistics with less recoil. When selecting a barrel for the long .224-cal bullets, specify a fast enough twist rate: “Sierra recommends a 1:6.5″-twist barrel for the #9290 22 cal 90 gr HPBT bullet. However, for cartridges like the Valkyrie, that can push them over 2650 fps muzzle velocity, a 1:7″-twist barrel will stabilize the bullet correctly.”

CLICK HERE to DOWNLOAD Complete Sierra .224 Valkyrie LOAD DATA.

.224 Valkyrie vs. .22-250 Remington
The Social Regressive explains: “There are two key reasons why the .224 Valkyrie is unique and desirable. First, it is specifically designed to fit the limitations of the AR-15 platform. It does so even when loaded with gigantic bullets, like the 90-grain SMK that Federal announced. The .22-250 Rem is too long and too fat to work in the AR-15 platform; it needs an AR-10 bolt and magazine.”

The .224 Valkyrie has been marketed as a low-recoil round that can stay supersonic to 1300 yards and beyond (with 90gr Sierra MatchKings). Here a Sniper’s Hide duo shots an AR-platform .224 Valkyrie at distances out to 1550+ yards. To be honest, the accuracy wasn’t that impressive. However this test confirms that the .224 Valkyrie does launch the long, heavy projectiles at high enough velocities to prove superior to the standard .223 Rem. Frank Galli (aka “Lowlight”) teams up with Brian Whalen of Colorado Precision Rifle at the Blue Steel Ranch in New Mexico.

The .300 Blackout — Risky Business

The .300 Blackout appeals to folks who want a .30-caliber defense round. This can be loaded at various velocities. Loaded at subsonic speeds and shot with a suppressor, the .300 BLK offers very low sound levels. Unfortunately, that .300 Blackout cartridge can fit in a .223 Rem chamber. Shooting a .308-caliber bullet in .223 bore is a recipe for disaster.

The .300 AAC Blackout aka “300 BLK”, is a compact 30-caliber cartridge designed to work in AR-15 rifles. It has a shorter cartridge case to accommodate the bigger 30-caliber bullet while still fitting in a standard AR-15 magazine. Unfortunately, that’s the danger. A careless shooter can toss a .300 Blackout cartridge in with .223 Rem rounds without noting. And because the case-head size is the same as the .223 Rem (5.56×45) the rifle’s bolt assembly will happily chamber and fire the .300 BLK round. Problem is, that forces a .308 diameter bullet down an undersized .223-caliber bore. Not good!

This images were provided by Tactical Rifle Shooters on Facebook. The message was clear: “Don’t try to run 300 Blackout in your .223/5.56mm. It won’t end well. The problem is identical rifles and identical magazines but different calibers.”

Image from Accurate Shooter Forum. Cutaway shows the jammed .30-Cal bullet:

For those who MUST have a .300 Blackout, here are some things you can do:

1. Use different colored magazines for .300 Blackout vs. .223 Remington.
2. Mark .223 Rem upper handguards with the caliber in bright paint.
2. Fit all your uppers with caliber-labeled ejection port covers.
4. Mark all .300 BLK Rounds with heavy black marker.

In June 2020, Hornady introduced the 6mm ARC, a new SAAMI cartridge optimized for AR-platform rifles*. The new 6mm ARC is basically a 6.5 Grendel necked down to 6mm, with the shoulder moved back around .030″. That pushed-back shoulder does reduce case capacity (and velocity), but we assume Hornady did that to create a shorter, proprietary chamber so people could not simply neck-down Lapua 6.5 Grendel brass, as has been done for years with Robert Whitley’s outstanding 6mm AR wildcat.

CLICK Image for official SAAMI Specifications:

If you are intrigued by the 6mm ARC, you’ll find the products you need at Brownells — uppers, barrels, bolts, and magazines. Brownells also sells Hornady-made 6mm ARC factory-loaded ammo, but most varieties are out-of-stock right now, as is the 6mm ARC brass. More brass and ammo should arrive soon. Midsouth is also taking brass/ammo backorders. For general information, see 6mm ARC Info Page.

What Is the 6mm ARC Cartridge?
The 6mm ARC cartridge is a new SAAMI-spec cartridge based on the 6.5 Grendel case necked down for 6mm bullets, with the shoulder moved back 0.030. Yes it is designed to run in AR15-platform rifles. You’ll need a new barrel, bolt, and mags. If you already have an AR chambered in 6.5 Grendel, the ONLY thing you need to change is the barrel. Everything else — bolt, magazines, gas system – is compatible with 6mm ARC.

▶ Official SAAMI Cartridge (not wildcat)
▶ Fits standard AR15-platform rifles
▶ Fits Short/Mini action bolt rifles
▶ Efficient short, fat case design
▶ 30-degree case shoulder

For more INFO, see 6mm ARC Info Page.

What Do I Need To Shoot the 6mm ARC?
Faxon and Ballistic Advantage are already producing barrels, with more manufacturers sure to follow. All the other required components are already on the market for 6.5 Grendel rifles. Aero Precision already offers complete 6mm ARC uppers.

If you’re converting a standard 5.56×45 mm (.223 Rem) AR15 upper to shoot 6mm ARC, you’ll need a 6mm barrel, a Type II 6.5 Grendel bolt carrier group, and new magazines. Some folks have suggested standard AR mags will work, but trust us, you want the magazines that have been designed for 6.5 Grendel. All the hardware you need is currently available at Brownells.

6mm ARC Videos from Hornady (18 Total)

* While 6-6.5 Grendel shooters are known to run stout pressures, the new 6mm ARC cartridge has a relatively moderate Maximum Average Pressure (MAP) rating of 52,000 psi according to the official SAAMI specifications. For a variety of reasons, is wise to keep pressures in a semi-auto rifle moderate. Don’t chase the velocities you might get in a bolt-action gun.

Today we feature a benchrest rifle that earned its place in history by setting a small-group record in 2013 that may never be broken. This .30-caliber benchrest rig shot a 0.0077″ five-shot group at 100 yards. That’s the smallest 100-yard group ever shot in competition by ANY gun at 100 yards in history. And we may never see anything smaller in our lifetimes.

In setting that .0077″ (seventy-seven ten-thousandths of an inch) record, the shooter, Mike Stinnett, broke a record that stood for four decades — the 0.009″ five-shot group credited to Mac McMillan. The previous NBRSA Light Varmint Record of .009″ for five shots (at 100 yards) was set on 9/23/1973, 49 years ago. Experts considered that record “untouchable”, “unassailable” — in other words “unbreakable.” But Mike broke Mac’s record 40 years after it was set.

The Record-Setting Rifle and Cartridge
The gun that produced the historic .0077″ group was a Light Varmint-class Benchrest rifle chambered as a .30-caliber wildcat, the 30 Stewart. That cartridge is based on the 6.5 Grendel case necked up. The load had Hodgdon H4198 powder behind BIB 114gr, 10-ogive bullets. Notably, the record-setting ammo was pre-loaded before the match.

The Smallest 100-yard Group in History

All target shooters strive for perfect shot placement. Well one man has come closer to perfection than any other shooter who ever lived. You are looking at Michael Stinnett’s .0077″ NBRSA world-record group, the smallest 100-yard 5-shot group ever shot in the history of rifle competition. The group was certified at .0077″ (though labeled .008″ on the range-signed target below). A moving backer verified that this was FIVE shots — no question about that. You may be surprised but this was NOT shot by a 6 PPC, but rather a .30-caliber wildcat, based on the 6.5 Grendel.

Group Is Smaller than ANY 100-yard Group Shot in ANY Class

Mike’s amazing group stands as a NBRSA Light Varmint Class record. But it is also smaller than the current NBRSA 5-shot, 100-yard records for ALL other classes, even Unlimited (Rail Gun). Likewise Stinnett’s .0077″ group is smaller than the IBS records for ALL classes:

Better than any Rail Gun too — Mike Stinnett’s .0077″ group was smaller that ANY group shot in ANY class — event Unlimited Rail Guns, as shown below:

Below is a larger-than-life-size view. Using this photo we measured the group with target-calculating software, and it came out .006″ (the software only goes to three digits). We recognize that it would be much better to work from the real target rather than a photo, so we are not challenging the official measurement in the least. But this does confirm that this is a phenomenally small five-shot group.

Stinnett Sets .0077″ Record with a .30-Caliber Modified Grendel Cartridge, Pre-Loaded
Many folks have asked about the gun and ammo that produced the .0077″ group. The rifle was chambered as a .30-caliber wildcat, the 30 Stewart, which is based on the 6.5 Grendel case necked up. Mike was using Hodgdon H4198 powder behind BIB 114gr, 10-ogive bullets. Notably, the record-setting ammo was pre-loaded before the match. Unfortunately, we don’t have a photo of the target yet — it is still in the hands of the official NBRSA certification committee. However, Mike has been kind enough to tell us about his rifle and his load.

Mike Stinnett .0077″ Record Group Equipment Report

Mike reports: “Several guys have asked so here is my equipment listing. The hardware build actually started in 2008 with the goal of building two identical Benchrest rifles which could be used for both group and score. The idea was to shoot 6PPC and a .30 Cal without a base rifle change.”

About the Cartridge — 30 Stewart (Based on Lapua 6.5 Grendel Parent Brass)
Mike explains: “Our goal was to shoot H4198 as the optimal powder for stability. There were several versions of the reamer before we settled on the current configuration. I am optimized for the 10 Ogive BIB bullet, powder to the base of the bullet. I found in testing the small 30-cal case did not like compression at all. The bullet is seated only 0.12″ into the case with zero freebore.

Cases were initially created with the .220 Russian (like a PPC) but I later decided it was better to build from the 6.5 Grendel. I size the brass and bump the shoulder back until it will fit into the chamber, fill to shoulder with International Clays, cotton wad packed on top. I have a fire-forming barrel. (I would not recommend this Clays and cotton wad method in a good barrel.) After initial fire-forming, I then mandrel the neck up the rest of the way to .30 caliber, turn the necks and trim.

It takes at least 8 firings to fully form a case! If you fire only three loads I find the brass does not have a sharp shoulder or any pressure on the bolt so any die selection is incorrect. Brass continues to harden well past 25 firings. I have match brass with well over 500 rounds fired, and I have never blown a case or neck yet (using my forming method).

For loading I use a Hornady Custom Shop Sizing Die and a Ralph Stewart Custom Seating Die. For those who are curious, yes the small group was fired with pre-loaded rounds. I do this now and then with local matches or may load 50 in a batch for one match.”

Mike wanted to thank his smiths, Randy Robinett, and all the folks involved in running the matches: “A big THANKS — as these are the guys that make our matches possible and without question maintain the integrity of the targets and record system. I was very fortunate to have all the right people in the right places for this match and my record. As for measurement – I only saw the target for about 10 seconds up close and can say I’m very happy I did not have to measure that group! Thanks again to everyone!” — Mike Stinnett

We’ve been fans of the Howa Mini Action rifles since they were introduced a few years ago. With actions that are nearly an inch shorter than typical “short actions”, these Mini Action rigs work great as a compact “truck gun” or carry-around varminter. Current chamberings are: .223 Rem, 6.5 Grendel, 7.62x39mm, and .350 Legend. There are 20″ heavy contour and 22″ standard contour barrel options, plus a 16.25″ heavy for the .350 Legend only.

6.5 Guy Ed Mobley Tests the 7.62×39 Howa Mini Action Rifle

The Howa Mini Action rifles come with the excellent HACT 2-stage trigger and a 5-round or 10-round, synthetic detachable box mag (depending on caliber). The Mini Action’s bolt is 13% shorter than on regular short actions, providing a shorter, faster bolt throw. Weight is also reduced. This makes for a nice, compact (and very shootable) package.

6.5 Guys Test Howa Mini Actions in 6.5 Grendel and 7.62×39

The 6.5 Guys recently secured a pair of Howa Mini Actions, one chambered in 6.5 Grendel and the other in 7.62×39 Russian: “After trying out the Howa Mini Action rifles at SHOT Show 2017, we got a couple of loaners in 6.5 Grendel and 7.62×39 courtesy of Legacy Sports. These rifles are known for their smooth cycling and lightweight actions, as well as some unique chamberings for bolt rifles (6.5 Grendel, 7.62×39). Long story short, we really enjoyed them.” In fact Steve liked his 6.5 Grendel enough that he plans to purchase the gun. Get the full scoop in this VIDEO REVIEW:

The folks at Legacy Sports also conducted extensive accuracy tests of commercial ammunition in 6.5 Grendel and 7.62×39. The most accurate 6.5 Grendel ammo, with a stunning 0.29″ group, was Alexander Arms with Lapua 123gr Scenar; second best (0.56″ group) was Hornady with 123gr A-Max bullet. The most accurate 7.62×39 ammo was Hornady 123gr SST with a 0.62″ group in the 20″ Heavy Barrel version. View Howa’s Test Reports with these links:

6.5 Grendel Factory Ammo Data | 7.62×39mm Factory Ammo Data

Click HERE for full-screen image.

Legacy Sports Video compares Mini Action Rifles in .223 Rem and 6.5 Grendel: