September 18th, 2019

Too Fast or Too Slow — What’s Your Optimal Twist Rate?

Glen Zediker Twist Rate .223 Rem Barrel Top Grade Ammo Midsouth
Here’s an extreme range of .224-Caliber bullets: 35gr varmint bullet and 90gr match bullet. Of course, along with bullet length/design, you need to consider MV when choosing twist rate.

Even with the same caliber (and same bullet weight), different bullet types may require different rates of spin to stabilize properly. The bullet’s initial spin rate (RPM) is a function of the bullet’s muzzle velocity and the spin imparted by the rifling in the barrel. You want to ensure your bullet is stable throughout flight. It is better to have too much spin than too little, according to many ballistics experts, including Bryan Litz of Applied Ballistics. Glen Zediker has some basic tips concerning barrel twist rates and bullet stability. These come from his latest book, Top Grade Ammo.

Choosing the Right Twist Rate
I’d always rather have a twist too fast than not fast enough. Generally… I recommend erring toward the faster side of a barrel twist decision. 1:8″ twist is becoming a “new standard” for .224 caliber, replacing 1:9″ in the process. The reason is that new bullets tend to be bigger rather than smaller. Don’t let a too-slow twist limit your capacity to [achieve] better long-range performance.

Base your next barrel twist rate decision on the longest, heaviest bullets you choose to use, and at the same time realize that the rate you choose will in turn limit your bullet choices. If the longest, heaviest bullet you’ll shoot (ever) is a 55-grain .224, then there’s honestly no reason not to use a 1:12″. Likewise true for .308-caliber: unless you’re going over 200-grain bullet weight, a 1:10″ will perform perfectly well.

Glen Zediker Twist Rate .223 Rem Barrel Top Grade Ammo Midsouth

Bullet Length is More Critical than Weight
Bullet length, not weight, [primarily] determines how much rotation is necessary for stability. Twist rate suggestions, though, are most usually given with respect to bullet weight, but that’s more of a generality for convenience’s sake, I think. The reason is that with the introduction of higher-ballistic-coefficient bullet designs, which are longer than conventional forms, it is easily possible to have two same-weight bullets that won’t both stabilize from the same twist rate.

Evidence of Instability
The tell-tale for an unstable (wobbling or tumbling) bullet is an oblong hole in the target paper, a “keyhole,” and that means the bullet contacted the target at some attitude other than nose-first.

Glen Zediker Twist Rate .223 Rem Barrel Top Grade Ammo MidsouthIncreasing Barrel Length Can Deliver More Velocity, But That May Still Not Provide Enough Stability if the Twist Rate Is Too Slow
Bullet speed and barrel length have an influence on bullet stability, and a higher muzzle velocity through a longer tube will bring on more effect from the twist, but it’s a little too edgy if a particular bullet stabilizes only when running maximum velocity.

My failed 90-grain .224 experiment is a good example of that: I could get them asleep in a 1:7″ twist, 25-inch barrel, which was chambered in .22 PPC, but could not get them stabilized in a 20-inch 1:7″ .223 Rem. The answer always is to get a twist that’s correct.

These tips were adapted from Glen’s newest book, Top-Grade Ammo, available at Midsouth. To learn more about this book and other Zediker titles, and read a host of downloadable articles, visit ZedikerPublishing.com.

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September 18th, 2019

REVIEW: AIM Field Sports FS-42 Rifle Bag with Shoulder Straps

AIM field sports carry bag folding rifle FS-42 FS case backpack

AIM Field Sports FS-42 Rifle Carry Bag (Shoulder Pack)

Gear Review by Jason Baney
I recently had the opportunity to test out the AIM Field Sports FS-42 rifle carry bag from the UK. This brand, while not well known in the USA, is popular throughout Europe as AIM makes incredibly robust and well thought-out gear. In addition to AIM’s house brand, AIM also sells OEM gear for other well-known companies, so this outfit is well-versed in the market and know what works and what doesn’t. These are incredibly well-made bags at a very fair price (£157.50, about $196.00 USD). I expect we will see more AIM rifle bags come to the U.S. market in the coming years.

AIM field sports carry bag folding rifle FS-42 FS case backpack

About the Rifle — Accuracy International AX in 22 Creedmoor
The rifle in the photos is Jason’s new “Groundhog Laser”, chambered in 22 Creedmoor. Jason reports: “The Accuracy Int’l AX platform lets me swap barrels quickly and the Tangent Theta scope allows quick zero resets when switching barrels. The suppressor is a Silencerco Omega and the scope mount is an ERATAC adjustable. With the 24″ 1:8″-twist Bartlein 5R barrel and a healthy charge of H4350 it runs a 75gr Amax just a touch under 3500 FPS for a 1000-yard come-up of about 5.3 mils!”

Jason added: “Even my 6-year-old son loves to shoot the rifle (with the LOP set at minimum). The boy took the first 7 groundhogs with it over a 2-hour span. I took 4 that day as well — an epic groundhog adventure. My son also recently shot this rifle at 1000 yards. On his very first 1K outing, he went 10 for 11 shots on a 2/3 IPSC target!”

For me, the FS-42 was intended to carry my Accuracy International AX (another fabulous tool from the UK) to and from the range, matches, and groundhog fields. While AIM Field Sports makes several types of Carry Cases and Drag Bags, this FS-42 is the model for right-side folding stock rifles up to a length of about 41.5.” AIM’s FXS-42 would be the choice for similar length rifles but with a butt-stock that folds to the left.

AIM field sports carry bag folding rifle FS-42 FS case backpack

Good Shoulder Strap System Provides Comfortable Carry
The backpack straps received quite a bit of use and are well designed and rugged — you hardly know they exist until you deploy them for use. I actually enjoyed carrying my heavy rifle even when loaded with a tripod (strapped on the external loops), ammo, bipod, mags, suppressor, camera gear and a couple bean bags. It had no problem handling my heavy rifle and gear. Even with a 24″ barrel with suppressor mounted, and large Tangent Theta 5-25 scope the bag had plenty of room to secure and protect it.

AIM field sports carry bag folding rifle FS-42 FS case backpack

The FS-42 gives plenty of room for support gear and has many well placed straps and reinforcements to keep your rifle in place and protected in transit. The more time I spend with it the more features I notice. It is obvious that these bags were designed by shooters. While no soft case/drag bag can quite offer the same protection of a hard case, it is much less cumbersome and holds about the same amount of gear. It is so well thought-out there is even a spot for a cleaning rod along the spine of the case!

Overall, the AIM FS-series bags are well-made, well laid-out and a great value in a world where some similar bags can be nearly twice the cost. These AIM bags are a great alternative to dragging heavy hard cases around.

Final Thought: “The FS-42 Bag is excellent — I dig it. It has worked well for all tasks. The only thing I would change is a bit more padding where the bag lies on your low-back/pelvis area.”

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September 18th, 2019

Lapua Teams Up with Vudoo Gun Works at WSC This Week

vudoo .22 LR rimfire lapua center-X

The NRA World Shooting Championship (WSC) starts today in West Virginia. The event runs September 18-21 at the the Peacemaker National Training Center in Glengary, WV. At the WSC, top professional and amateur shooters compete in a wide variety of shooting disciplines, including pistol, rifle, shotgun, and combined firearm sports.

As a key part of this event, Lapua will team up with Vudoo Gun Works on a special “tactical rimfire” stage. This allows shooters to enjoy the fun of PRS-style shooting with a rimfire cartridge. Lapua’s Center-X ammunition will be paired with a state-of-the-art Vudoo .22 LR rifle. On this stage, competitors will engage challenging targets at multiple ranges.

vudoo .22 LR rimfire lapua center-X

Even if you can’t make it to the World Shooting Championship, rimfire shooting with a Vudoo rig (or similar rifle) is a great way to cross-train for PRS/NRL with lower cost ammo. Factory loaded centerfire can easily cost $1.50 per round. Rimfire .22 LR ammo is a fraction of that cost. You can get good SK and Lapua ammo starting at about $6.50 per 50ct box. That’s just 13 cents per round.

“We are excited to return to the NRA World Shooting Championship at Peacemaker. As we did for the past two years, we are teaming with Vudoo to display the accuracy capabilities of Lapua ammunition. I think the shooters will be thrilled with the performance of Lapua Midas+ and Center-X ammunition in the Vudoo rifles. This event is a great test for shooter and equipment,” stated Adam Braverman, Lapua Director of Sales and Marketing.

Permalink Bullets, Brass, Ammo, Competition No Comments »