I typically ran 2920 ish with 36.X gr H4350 from 28in barrels. Just keep adding powder to get the speed you want. It'll do just fine at your current velocity.
6gt
- Thread starter Dthomas3523
- Start date
Yeah I’ve been thinking of tossing more powder in there. I’ve heard around 2900 is a sweet spot.
I think the proverbial "sweet spot" depends on what one is going for...
I've been shooting my current barrel at ~2800fps its whole life, and initially I was more about going "slow" and going after seeing how soft shooting I could get it (to help with seeing more and spotting more impacts/splash). But if I'm honest, I've also been toying with the idea of adding powder and going faster that whole time too (knowing that it seems most PRS guys are running closer to ~2900fps with the GT).
That said, I've got something like ~2200rds on the barrel now, and while I know I'll be pulling it soon, it's still hammering and shooting lights out just like new with the first ~300rds, just like it always has. Single-digit SDs the whole time (~5-6 over 20 shots). So every time I go to tweak my load, I end up reminding myself how dumb it could potentially be to ruin a good thing, and then don't end up doing it lol.
I guess my point is, if one's load is hammering out far and printing small groups, the speed doesn't matter and there's no reason to try to keep up with the Joneses as far as speed for no good reason.
I could see trying to push a little harder to produce more smack/feedback off plates (and possibly more splash), but if already running 109-115s, I don't know if pushing it would even matter and be worth trading the brass/barrel life?
FWIW, my brass (Alpha Gay Tiger headstamp) has 15 firings on it over 2 barrels now, and I plan on using the same brass with my next barrel too (the pockets are still tight and the only cases I've lost were to matches/props, I anneal every firing on an AMP and the rest is still about same as new).
I’m not real keen on working for max velocity in a target rifle. Myself, I shoot what proves most accurate as determined by testing actual results on paper and steel. When I establish the accuracy I want, i let the scope dials do the rest of the work. Pushing that barrel for that last 25 to 50 fps just to say I got that last 25 to 50 fps, means very little on the range, but it’s tough on the barrel. (Shooting Varget in one rifle with 105’s gives me just over 2900 in one rifle and 2850 in the second rifle, identical loads, go figure)
Caveat. Since I limit the distance I take while hunting (it’s an age thing) and my favorite hunting rifle has a markedly slow barrel, I do push its velocity. But I don’t dial, i only take shots at known distances below my max and can use point of aim at all distances. It’s accurate for what it is, and when actively hunting, I rarely shoot it more than 20 to 25 shots a year.
Caveat. Since I limit the distance I take while hunting (it’s an age thing) and my favorite hunting rifle has a markedly slow barrel, I do push its velocity. But I don’t dial, i only take shots at known distances below my max and can use point of aim at all distances. It’s accurate for what it is, and when actively hunting, I rarely shoot it more than 20 to 25 shots a year.
Almost exactly what I ran in my last barrel, which was a 26" 7.5tw Bart, from Stuteville, except I was running the 108 Berger (velocities between the two bullets for same charge weight are pretty similar in my experience)
Opinions on trim length for 6 gt? I see the published case dimensions are 1.725" +0.000/-0.020 so I went to 1.7075" to keep a little margin but also to keep me from having to ever trim again. I'm told these cases don't grow much. But friend told me that if i trim this short, it'll lead to carbon fouling in the neck and throat. Can any experienced 6 GT users chime in on this?
I set my Henderson to barely give the inside and outside a chamfer and debur but I only have 2 firings in 500 of my 800 alpha brass.
The more room in the throat, the wider the ring of carbon fouling. You're never going to eliminate it, so you'll have to tackle it regardless. However, with a shorter case neck you'll have more to scrub.
Where is the lapua brass? They announced it 2 years ago........then crickets.
It's just starting to show up, there is a post over on Accurate Shooter about it.
So I’m 1400 ish rounds into my barrel with a .170 freebore. Has anyone started with a large jump in a similar freeboard and adjusted as the barrel eroded?
My first barrel was 120fb, last 6 have been 170. I typically start a 109hyb at 40 or 60 off and leave it there. Add powder as lands erode and pressure drops to keep the desired velocity. Do the same with 115 dtacs.
Alright I started with .025 off the lands and now it’s at .059 at 2846 with 36.5g H4350. So I may bump it up to 36.8g
Is it still shooting well? I'm typically at mid 36.X jumping 40-60k around 2920 with 28in barrel, after 2.5k rds im jumping approx 0.150-0.170 avg. And I'm at mid 37.X to keep the speeds at low 2900s. I burned 4 barrels with 109s, now I primarily shoot 115 dtacs started at 50k off lands and I just leave it there and add powder to keep it in the low 2800s for velocity. I've found throat movement to be about 30% less, I'm alos burning about 1.4gr less H4350 on avg.
It’s shooting well. With it being Texas I felt the velocity was a little slower this past weekend at 2846 for shooting in 80+ degree weather. I was used to 2860 ish last summer. Even in February I was getting 2870 ish over 40 rounds.
Last edited:
On two barrels, now (Berger 108s with H4350 and Bartlein 5R in one, Berger 109s with Varget and Krieger 4gr in the second), my throat erosion runs about .006"/100 rounds. Running it between 2800-2840, so not standing on it. What I've noticed, too, is that once I'm jumping .050-.060, I don't see a huge difference in pressure/velocity with more jump.
Well hopefully everyone is following a brass spec based of the saami 274 nk chamber, which is where all the alpha chambers are at. As long as you're 2685-270 loaded diameter you're good to go.
I
that’s a lot of shooting. Do you stick with one CBTO for a given bullet for the life of the barrel?
"I primarily shoot 115 dtacs started at 50k off lands and I just leave it there and add powder to keep it in the low 2800s for velocity."
^^^^^^^ This is what he said
^^^^^^^ This is what he said
I’m finishing out my second barrel with DTACS, got a JTAC class this weekend and I’ll pull it when I get home and put the new one on. On both I’ve pretty much found the BTO that shot best and left it there for the life of the barrel. Two completely different free bores and both shot really good in the .050-.060 off range with the 115’s.
Yes, I typically just leave it at that seating depth for life of barrel unless all a sudden group size gets big. However these smaller capacity 6mms will typically hold half minute 5-10 shot groups for a very long time.
I went to DTACs on my last barrel too. I set them at .045 which is just in front of neck shoulder junction with a .120 Freebore. 37 of N160 @ 2845. Just put a new barrel on my GT. Hope to shoot it this weekend.
The one I have on now will have right 2500rds on it after the class. Still shooting good but the velocity is dropping off. The last one I pulled it at just over 2400rds
I have yet to actually kill a GT barrel. Pulled wife's at 2800 and it was still shooting, but getting long in the tooth. Probably would have died between 3200 and 3500, my best guess. She was running Berger 109s at 2930 with 33.7 of RL15.5. It seems they all have started to drop velocity around 2500, so I don't go much farther and just pull them.
Sounds like I have had a similar experience to you guys…
Pulled my 1st GT barrel at 2500rds and it was still shooting, but had lost ~50fps, and towards the end seemed to shoot great for ~150rds after being cleaned and then start to get a little wonky until I cleaned it again. I shot DTACs with 34gr of SWPR for 600rds at ~2900fps, then downshifted to 33gr for ~2800fps for rounds 601-1500 with the same lot of DTACs. The DTACs were as good as it gets in the GT IMHO. I shot 112 Match Burners on the backend and they’re really good too (and not just for the money). I don’t think it’s totally toast, I could probably squeeze another ~500 training rounds out of it.
I’ve got ~2300 on #2 and think I’ve lost ~25fps, I’ve cleaned it every 250-300rds and it’s still hammering. All 106gr DOD A-Tips. 33gr SWPR for a soft 2850fps (now 2825fps).
I’m going to DTACs for the next barrel. I’m planning to seat the bullets as short as I can while keeping the bullet’s bearing surface above the neck/shoulder junction (even though I’m not convinced that matters), dropping 33gr of Varget, and then just shooting it.
All .119 freebore SAAMI Proof prefits, as long as I’m not jammed I probably won’t even measure for the lands (of course I will).
FWIW, I’ve decided I’m now a full-on “Reloading-Atheist” lol. I don’t really care about tenths of a grain of charge weight or seating depth, or any magical “node”, etc BS anymore. Now, all I really care about is that every single one of my rounds comes out exactly the fucking same as the next. I’ve been doing this for a few barrels now, with SDs in the single digits and .3” average 100 yard groups, and I am convinced, it might just be as simple as: just be a badass ammo factory and it will shoot.
Pulled my 1st GT barrel at 2500rds and it was still shooting, but had lost ~50fps, and towards the end seemed to shoot great for ~150rds after being cleaned and then start to get a little wonky until I cleaned it again. I shot DTACs with 34gr of SWPR for 600rds at ~2900fps, then downshifted to 33gr for ~2800fps for rounds 601-1500 with the same lot of DTACs. The DTACs were as good as it gets in the GT IMHO. I shot 112 Match Burners on the backend and they’re really good too (and not just for the money). I don’t think it’s totally toast, I could probably squeeze another ~500 training rounds out of it.
I’ve got ~2300 on #2 and think I’ve lost ~25fps, I’ve cleaned it every 250-300rds and it’s still hammering. All 106gr DOD A-Tips. 33gr SWPR for a soft 2850fps (now 2825fps).
I’m going to DTACs for the next barrel. I’m planning to seat the bullets as short as I can while keeping the bullet’s bearing surface above the neck/shoulder junction (even though I’m not convinced that matters), dropping 33gr of Varget, and then just shooting it.
All .119 freebore SAAMI Proof prefits, as long as I’m not jammed I probably won’t even measure for the lands (of course I will).
FWIW, I’ve decided I’m now a full-on “Reloading-Atheist” lol. I don’t really care about tenths of a grain of charge weight or seating depth, or any magical “node”, etc BS anymore. Now, all I really care about is that every single one of my rounds comes out exactly the fucking same as the next. I’ve been doing this for a few barrels now, with SDs in the single digits and .3” average 100 yard groups, and I am convinced, it might just be as simple as: just be a badass ammo factory and it will shoot.
Last edited:
Pretty much what I do. On a new barrel I’ll load up a generic charge with start of the bearing surface just slightly above the neck/shoulder junction and shoot a couple one day matches. Then I’ll stuff enough powder in it to get the velocity I desire. For me and shooting DTACS I like 2800-2810 range. Then I’ll load 5 rounds of three different seating depth(.040,.050 and .060) test at 500yds and go with the one that looks best. Very minimal load development.
I have enough 109’s to get to 2750 ish on this barrel which may be pushing it but I want to try Dtacs in my next one. Already have a .120 freebore prefit waiting.Sounds like I have had a similar experience to you guys…
Pulled my 1st GT barrel at 2500rds and it was still shooting, but had lost ~50fps, and towards the end seemed to shoot great for ~150rds after being cleaned and then start to get a little wonky until I cleaned it again. I shot DTACs with 34gr of SWPR for 600rds at ~2900fps, then downshifted to 33gr for ~2800fps for rounds 601-1500 with the same lot of DTACs. The DTACs were as good as it gets in the GT IMHO. I shot 112 Match Burners on the backend and they’re really good too (and not just for the money). I don’t think it’s totally toast, I could probably squeeze another ~500 training rounds out of it.
I’ve got ~2300 on #2 and think I’ve lost ~25fps, I’ve cleaned it every 250-300rds and it’s still hammering. All 106gr DOD A-Tips. 33gr SWPR for a soft 2850fps (now 2825fps).
I’m going to DTACs for the next barrel. I’m planning to seat the bullets as short as I can while keeping the bullet’s bearing surface above the neck/shoulder junction (even though I’m not convinced that matters), dropping 33gr of Varget, and then just shooting it.
All .119 freebore SAAMI Proof prefits, as long as I’m not jammed I probably won’t even measure for the lands (of course I will).
FWIW, I’ve decided I’m now a full-on “Reloading-Atheist” lol. I don’t really care about tenths of a grain of charge weight or seating depth, or any magical “node”, etc BS anymore. Now, all I really care about is that every single one of my rounds comes out exactly the fucking same as the next. I’ve been doing this for a few barrels now, with SDs in the single digits and .3” average 100 yard groups, and I am convinced, it might just be as simple as: just be a badass ammo factory and it will shoot.
You guys have me wanting to bump my speeds down a little. 36.0 H4350 gets me 2940 with 105's. Maybe I should bump it down to 34.8. Case fill might start to get a little low.
Where is the ES/SD and accuracy at? No point in messing with success, and if you are getting great speeds at obviously not overpressure charges... this becomes a case of 'if it ain't broke, don't fix it.
Just MO.
Just MO.
I would stay there. I wish I was getting that much velocity out of 36.0
My new lots of H4350(last few years of purchase) are around 1gr slower in the 6gt than my stuff from years prior. Post covid H4350, H1000 has def been slower burning. However my varget has been close, but still see definite lot to lot variations. This will make a difference in people's data of I'm at 36.0 VS 37.0 for XXXX speed.
Yep.
I have a 6.5x47 that shot lights out with some older H4350. When I switched to a new lot, I had to drop .6gr to get back into accuracy and the same velocity.
I’ll have to see if i can get mid 2900’s with my staball 6.5 practice loads. I was at 2850ish with 38.0 so i just loaded a couple dozen at 38.9 to see how it does.
