Reloadg Equipment - WTB Alpha 6GT Gay Tiger marked brass | Sniper's Hi Fom

Author's note: My ctom 6mm GT rifle build article n be found velopment for a new rtridge n often be analogo to a science project and ually requir a lot of experimentatn before an optimal formula is found. The 6mm GT is a fairly new rtridge whout much load data the major loadg manuals; however, the rtridge signers, Gee Gardner of GA Precisn and Tom Jabs of Vapor Trail Bullets, have published a loadg formula, which is a great place to straight om GA Precisn's webseEfficient Case Dign: Optimized se nearg 100% pacy wh 34-35.5 gras of Varget.Velocy: 3020-3080 fps wh 103-105 gra bullets and approx 3000 fps wh 115' we get to load velopment, let's take a look at the ponents I ed.POWDERPowr choice was easy, kd of. Sce I uld not fd Varget, I ed Vihtavuori N140, and Shooter's World Precisn, sce the were siar to Varget. Var foms and load velopers stated that StaBall 6.5 and H4350 also work great a 6mm GT.BULLETSBullet choice was pretty easy as well. I already had a se of 105 gra Lapua Scenar-L and a uple of s of 108 gra Berger BT Target the reloadg room, so we went wh those. The ultimate goal was to e 109 gr Berger Long-Range Hybrid Target. Still, we uld not source this bullet at the begng of load velopment, though we recently got some and worked up a load wh . (More on this later)BRASS AND PRIMERSFor brass s, there are 2 ½ optns: you have the budget optn om Hornady ($0.75/piece) and the premium optn ($1.25/pc), Alpha Brass. As a bon optn, Alpha ma the "GAY TIGER" stamped brass exclively sold through , so naturally, that's the optn I chose.Primers were an easy cisn for me as well. I jt went wh what I had a plethora of on hand, CCI 450 Small Rifle Magnum. Other good optns would be Feral GM205M, CCI #41, and CCI BR4. We are aware of the stat of primer ventory at the time of wrg (SEPT' 21) so e whatever Small RIFLE primers you n get your hands DEVELOPMENTBefore we get to the velopment procs, let's knock a uple of thgs out first:Disclaimer: This article is for rmatnal purpos only; all load data is for my rifle specifilly. Before loadg your ammo, reference published load data om bullet and powr manufacturers.Handloadg equipment ed:Prs: RCBS Rock ChuckerDi: RCBS 6mmGT MatchMaster setPowr Measurer: Fx120i wh AutoTrickler v. 2.5Primer: Lee Bench PrimerBrass Prep Statn: RCBS Prep StatnAnnealer: AnnealeezTumbler: Frankford Arsenal Quick N EZ Tumbler w/ Lyman rn b mediaBefore ttg my loads, I did a barrel break-/fire-formg. I load 50 rounds wh a safe load of 38.0 gras of StaBall 6.5 behd 105-gra scenar-L while nng cleang patch every uple of rounds.Sinote about barrel break-: everyone's opn on barrel break- is different; if you don't have your rual, nsult your barrel/rifle manufacturer for their suggted break- breakg the barrel , I ran a uple of 10 round velocy ladrs wh the Berger 108 gra BT Target, what some refer to as the Satterlee this, you take your max charge for the selected powr; this se, was 34.6 gras of N140 and Shooters World Precisn (to be wrten as 'SWP") and backed off 2 gras. You then load up ten rounds 0.2-gra crements back up to the max charge and shoot them over a chronograph to intify stable veloci over multiple charg, otherwise known as flat spots or the mythil velocy no. Here's what I found:ANALYZING THE DATASo what do we do wh the numbers? In theory, loadg up rounds the nos should produce tight standard viatns (SD) and small extreme spreads (ES) of veloci, leadg to small groups. However, this is a ty sample size.Lookg at the numbers, I realized pretty early on that the Shooters World Precisn would not reach the veloci I was lookg for (2975-3000 fps) wh the 108-gra bullet wh a safe powr charge. I stopped load velopment wh this powr and chose to e N140 until I uld get my hands on Varget and 109 gra were three nos for me to work wh here: 32.8-33.2, 33.6-33.8, and 34.4-34.6. If my primary goal were to shoot ty groups at 100 yards, I would have gone wh the larger no wh the slower speed. But this load is for PRS petn, shootg 1-2 MOA targets out to 1000 yards, so while I do need nsistency wh small SDs and ESs, I also need good this se, I'm lucky. There's a no at the max charge that is right around the target velocy. I chose to go wh the middle of that no and load up wh 34.5 gras of there, a seatg pth has to be tablished. There are a few ways to do this; the easit would be g the Hornady OAL gge wh a modified se. Unfortunately, I do not have one, so I have to do the good old "gus and check" uld be almost a whole article self, but the quick and dirty of is as follows:Take a prepped se and a h bullet wh some se lube on the ogive, put the chamber, and close the bolt. Open the bolt and hope the se out wh the bullet . Measure the bullet om the rtridge base to ogive. Subtract 0.020" om that measurement, and that's your startg seatg pth. Of urse, you should repeat that procs 3-5 tim and take an average. Still, I planned on shootg several different seatg pths to fd the right one for my chamber, so I started wh a CBTO, or rtridge base to ogive, of 2.010."Somethg to note, different bullet shap like to be jumped om or jammed to the barrel's lands at different distanc. Also, factory barrels typilly have a longer throat so gettg anywhere near the lands is impossible if you're feedg om a Tip: if you have vertil strgg your groups, that's typilly a velocy or body posn issue. The nsistenci n be addrsed by fdg your velocy no and improvg body mechanics. If you have horizontal strgg, that is often a harmonic issue or improper trigger manipulatn. Adjt your seatg pth, and work on trigger manipulatn.INITIAL TESTINGEvery once a while, you get lucky on your first try. The 108 gr bullet load wh 34.5 gr. of N140 at a CBTO of 2.009" turned out to be a wner. It gave me a velocy of 2976 fps wh an SD of 7 fps and ES of 19 fps. It also yield a 0.353" got tertg wh the 105 gr Lapua bullets. After tablishg a charge weight of 34.8 gras of N140, I achieved veloci near the 3000 fps marks and SDs between 4-6, but I was not groupg nsistently. Time to look at CBTO or rtridge base to ogive. Startg at 2.010", I shot 5 – 5 round groups 0.005" crements (2.008", 2.004", 1.998", 1.993" and 1.988"). The rults blew my md. Three of the five groups were unr 0.400", and they were all unr 0.500". Ultimately I cid on a CBTO of 2.000" those WERE my 2 loads:-108 Berger/34.5 N140 @ 2.010” CBTO flyg at 2975 fps-105 Lapua/34.8 N140 @ 2.000” CBTO flyg at 3000 fpsFortunately for me, I stumbled upon a 500-unt box of 109 gra Berger LRHT and a uple of pounds of Varget. After gog through the load velopment procs, I settled 34.6 gras of Varget behd the jump tolerant 109s load at a rtridge overall length (COAL) of 2.600". They're flyg at 2990 fps wh an SD of the groups? They are fe.CLOSINGThis is not the end all be all procs for load velopment, but works for me. There are plenty of other optns, cludg the popular Optimal Charge Weight (OCW). My suggtn is to fd what works for you and go wh , but don't expect to go easy every time, and don't be aaid to experiment. I will be experimentg wh new powrs and bullets as I fd them the off-season, so keep your ey THE AUTHORWilliam Maxwell currently serv the Uned Stat Army. After returng om his first ployment 2015, he started buildg firearms and foced heavily on pistol and rbe trag. In 2018 he fell to the rabb hole of precisn rifle shootg. He spends his ee time petg, reloadg, edg digal ntent, and wrg. He n be reached via Instagram @maddmaxxguns.