August 9th, 2020

Sunday GunDay: Texas Precision — Mike’s 6mm GT Rifle

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-Class

The 6mm GT (aka 6GT) cartridge was conceived as a “bigger Dasher” for PRS and NRL competition. The 6mm GT’s creators wanted 6mm Dasher accuracy and moderate recoil delivered via a cartridge with a slightly longer case body for better mag-feeding, longer neck for seating flexibility, and more moderate pressures. So far the 6GT has performed very well in PRS competition. Today’s story is a bit different — this is about an experiment — running a 6mm GT in an F-TR type rifle. Understand that, under current NRA rules, you may only shoot .223 Rem (5.56×45) or .308 Win (7.62×51), in official, sanctioned F-TR competition, but the 6GT is fine for F-Open. Mike McCasland wanted to see the potential of the cartridge for long-range target shooting, so he put a 6mm GT-chambered Bartlein barrel on a nice custom rifle with McMillan XIT stock and Kelbly F-Class Panda action. The results were impressive.

6mm GT — New Cartridge with Multi-Discipline Potential

Story by Mike McCasland, Texas Precision
The 6mm GT began garnering attention within PRS circles in early 2019. It promised to shoot 105-110gr 6mm bullets at 2950-3000 FPS, yet not suffer from mag-feed issues sometimes found with 6mmBR variants such as the 6 Dasher, 6BRX, and 6BRA. Moreover, since it burned less powder, the 6mm GT promised increased barrel life compared to the 6mm Creedmoor or 6XC. The 6mm GT case size should still work with the accurate powders in the Varget burn-range. I found the 6GT also worked great with H4350.

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-ClassAs someone who aspired to building a repeater and jumping into the PRS game, and had a spare F-TR rifle sitting around, I thought it would be fun to build up a 6mm GT to see if there was any merit to the hype. My smith, Wes Ripley of RIP Precision in Texas, builds a lot of PRS rigs, and already had the reamer on hand (a 0.120″ freebore variant).

Whidden Gunworks had some 6mm GT FL bushing die kits in stock, so I figured why not see what all the fuss was about? At the very least I could play around with the 6mm GT in F-Open Class at local club matches to see how it compared to the 6BRA, 6 Dasher, and other popular 6mm cartridges.

How the Project Got Started with Backup F-TR Rig
My 6mm GT build really started as a project spawned purely from COVID-19 Isolation boredom. This rifle primarily serves as a backup F-TR gun, and it had been relegated to performing some load development on .308 barrels, so I could spin new ones on my main match rifle. The only problem was, I had run out of .308 barrels that needed load development. So, I basically had an ideal test platform just collecting dust in the safe. All I needed was a 6mm GT-chambered barrel, since (like the 6mmBR) the 6mm GT works in a short action with a .308 Win-sized bolt-face.

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-Class

6mm GT Rifle Specifications:

Action: Kelbly Panda F-Class SA RB/RP
Stock: McMillan XIT with RAD 2A
Barrel: 30″ 5R Bartlein 1:7.5″-Twist, HV Contour

Scope: Vortex Golden Eagle 15-60x52mm
Trigger: Jewell Benchrest, about 2 ounces
Bipod: Phoenix Precision

About the 6mm GT Cartridge

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-ClassBRASS — The first thing you’ll find is cartridge brass choices for the 6mmGT are rather limited currently. At present, the only commercial options are Hornady and Alpha Munitions. For the die-hard Lapua fans, you can technically make 6mm GT brass from 6.5×47 Lapua, however that process is very labor-intensive.

I have used both Hornady and Alpha brass in this rifle and haven’t noticed much difference between the two. I will say that my batch of Alpha brass was slightly softer than Alpha brass I’ve used in other calibers; you could feel a difference when neck turning cases. I’m unsure if that’s a batch issue, or something specific to their 6mm GT brass as a whole. As far as performance, there was little discernable difference. Oddly enough, the Hornady brass seemed to have slightly less case capacity than the Alpha; with most other cartridges it’s the other way around.

POWDERS — The 6mm GT was designed with Hodgdon Varget in mind, and that popular powder works exceedingly well in this platform. That said, the 6mm GT can work with a wide variety of powders, some yielding better performance than Varget.

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-Class

I’ve tried a multitude of powders during my initial 6mm GT load development: Varget, Shooters World Precision, RL16, VV N140, H4350, and RL-15 to name a few. In my barrel, Hodgdon H4350 seems to deliver the best velocity/accuracy combination. SD and ES also seemed to be the lowest with H4350.

Load Development for the 6mm GT — Many Powders Tested
mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-Class

BULLETS — The most common 0.120″ freebore chamber allows for the majority of high-BC 6mm projectiles found in both F-Class and PRS. I had good luck with the pointed 107gr Sierra Match Kings (SMK), as well as the 110gr Hornady A-Tips in my rifle. For those looking to run the heavier 112-115 grain 6mm offerings, I believe GAP designed a 0.160″ freebore reamer that gets those bullets out of the neck/shoulder junction. Shown below is the 0.120″ freebore JGS reamer print:

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-Class

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-ClassSUMMARY — Good Cartridge with Much Potential
Generally speaking, I think the 6mm GT is a good little round. Some may not subscribe to this theory, but I believe some cartridges are inherently easier to tune than others. I’m not sure the 6mm GT is as easy-to-tune as a 6mmBR, 6 Dasher, or 6 BRA, but I don’t think it lags that far behind.

With relatively little trouble, I was able to find loads with both Varget and H4350 that would consistently shoot very well — 0.2 to 0.3 MOA. Moreover, I found the 6GT cartridge lives up to the velocity claims made by G.A. Precision. I was easily able to push the 110gr A-Tips to 2950 FPS, and the 107gr SMKs to low 3000 FPS range without any pressure signs, or unnecessary wear and tear on the brass.

As a fun test, I ran my 6mm GT rifle in a local 1000-yard F-Class match with the 110gr A-Tips, just to see just how well they would perform. Although wind conditions of the day and some E-Target issues prevented my 6mm GT rig from getting the better of the larger 7mm and .30-Cal rifles, the 6mm GT proved itself an accurate little round at distance. Here is a 1000-yard ShotMarker target:

mike mccasland 6mmGT 6 GT alpha brass 6BRA PRS F-Class

After putting several hundred rounds through my 6mm GT rifle, I anticipate building another 6GT on a repeater action to give PRS a try. I think if you are looking for a dual-purpose rifle that can run tactical matches (with 100% feeding reliability), and can also be used for mid-range, F-Open Class competition, the 6mm GT would be a very good option.

About the author, Mike McCasland:
Mike McCasland is an avid shooter who competes regularly in F-Class matches. Based in Texas, Mike is the creator of the Texas Precision YouTube Channel. There you’ll find many videos covering reloading, gun projects, and marksmanship. Mike has done some notable product reviews including a comparison test of Micrometer Competition Seating Dies. To access Mike’s YouTube Channel, CLICK HERE.

6mmGT 6 GT alpha brass mike mccasland PRS F-TR

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March 6th, 2019

Bargain Brass: 6.5 Creedmoor or 6.5 Grendel under $40 per 100

Cheap 6.5 Grendel Brass 6.5 Creedmoor CM 65 six five hornady

Are you a PRS shooter or tactical competitor who may have to leave cartridge brass on the ground during a match? Or are you a varmint hunter who may need 1000+ cases for a big varmint safari? Here’s a deal for you — 6.5 Creedmoor and 6.5 Grendel brass for under forty cents ($0.40) per case. Right now Midsouth is running a big sale on bulk-bag, Hornady-brand 6.5 Creedmoor and 6.5 Grendel brass. The 6.5 Creedmoor is $194.99 for 500 cases, while the 6.5 Grendel is $184.99 for 500 cases. Either way you’ll pay less than $40 per hundred. Compare that to $110+ for some premium brands of brass for these cartridge types.

Cheap 6.5 Grendel Brass 6.5 Creedmoor CM 65 six five hornady

“Wait a minute”, you might say, “why would I want Hornady brass — shouldn’t I be using Lapua brass instead?” Well yes, in most situations you should use Lapua brass — you get what you pay for. Premium Lapua brass will deliver better ES/SD, better accuracy, and last longer (a LOT longer).

However, there are situations when you cannot recover your brass during a match or the range does not allow you to retrieve brass. Rather than leave precious Lapua brass on the ground, this cheap Hornady brass is a cost-effective alternative.

Likewise, if you need hundreds (or even thousands) of cases for a varmint hunt, where sub-MOA accuracy will suffice, you may want to buy this Hornady brass to get more quantity for your money. With this deal you can get FIVE HUNDRED cartridge cases for less than you’d pay for 200 premium 6.5 CM or 6.5 Grendel cases. That makes a difference when you may prepare 1000+ rounds for a multi-day varmint safari.

Permalink Bullets, Brass, Ammo, Hot Deals, Tactical 2 Comments »
October 7th, 2017

Excellent Factory Ammo Offered by Creedmoor Sports

Creedmoor Sports Ammunition Powder Anniston Alabama

You may not know this, but Creedmoor Sports sells very high-quality loaded ammunition crafted with top-quality bullets and premium-grade Lapua brass for .308 Win and .30-06. We have friends who have shot some of this ammo in .223 Rem and .308 Win, and it is very impressive. The 6.5 Creedmoor ammo is capable of winning PRS matches outright. Creedmoor’s rifle cartridge match ammunition includes:

.223 Rem: (55gr FMJ, 68gr HPBT, 69gr TMK, 75gr HPBT, 77gr TMK)
6.5 Creedmoor: (140gr HPBT Hornady, 140gr HPBT Nosler, 142gr Sierra — all Hornady brass)
.308 Win: (155gr, 167gr, 168gr Sierra, 175gr all in Lapua Brass; also precision hunting in other brass)
.30-06 Springfield: (167gr Lapua Scenar HPBT in Lapua Brass)

Use Coupon Code CS929 to receive Free Ground Shipping on orders over $99!

Creedmoor Sports Ammunition Powder Anniston Alabama

Oh, the beauty of it — all that Lapua brass. From Finland with love….

Creedmoor Sports Ammunition Powder Anniston Alabama

What does 13,005 pounds (6.5 tons) of powder look like? That would last most reloaders a few seasons. Hoarders, eat your hearts out….

Creedmoor Sports Ammunition Powder Anniston Alabama

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