I have about 1k rounds down my x caliber barrel on my 6gt. I've been shooting all alpha brass and the same lot 112 match burners. I shot a match last month with no issues with my rifle all groupings and speeds were fine. I took my left over ammo I had from the match and went up and practiced with it. I rechecked my zero since it's been a couple months since I last shot it. My groups were no better than 2.5 inches. Where as with the same ammo 2 months ago was about 1/2 moa. I put the chrono on it and I'd get 3 shots that are at my normal speed (2950). Then I'd get 2 fliers that had speeds about 2875. This was the same for about 5 groups shot. I went home and cleaned the barrel really well and went back and tested. Same thing was happening. Groups went down to about 2moa but still the same fliers and and velocity deviation. I'm curious if my barrel is done already or is there anything else I should try?
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6gt problems
- Thread starter Avigerman
- Start date
Have you adjusted the seating depth since you developed this load?
My 6XC's throat moved about .070" in 1300 rounds and was shooting poorly. I moved the bullet out, to a .015" jump - like before, and it went back to normal.
My 6XC's throat moved about .070" in 1300 rounds and was shooting poorly. I moved the bullet out, to a .015" jump - like before, and it went back to normal.
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Have you checked for carbon ring in your barre? Usually you see a pressure/velocity spike which those though.
As mentioned above, could be your seating depth has changed so to throat erosion.
As mentioned above, could be your seating depth has changed so to throat erosion.
Wouldn't seating depth effect all rounds, not just a few? I'm going with the carbon ring since you only have about a 1000 rounds on the barrel. Also, check your barrel crown. Again, I would expect an issue to effect all rounds if that were the issue. You might also try loading some new ammo. How many firings on the current brass? And what/how are you processing fired brass?
We don't have data on the ES from the beginning, so we only know that the groups have opened up.
In my case, I also discovered my load went to hell after a good cleaning. Either way, re-working the load was the solution.
I my 300 pieces are on about 4 firings now. They way I prep my brass is decap with decapping die. Dry tumble. Anneal on anneleeze. Resize and trim if needed.
I found the 112s to be very inconsistent even in same lot. I prob shout 150 of them for load development with H4350 and rl16 in my gt. Never had consistent accuracy. Id get a screamer group at 400y, sub 1.5" then it'd be 3"+ next group. I found they liked a lot of jump, 75k off was where I found best results. I found the 108 and 109 bergers to tune in far easier and have shot 1700 109s through the barrel. Original seating depth was 40k off, that same seating depth is now a shade over 100k jump due to erosion. It still shoots half moa at 500y. I added 0.1gr of H4350 to keep the speed at 2910, thats all the tweaking I've done with it.
I had random unexplainable fliers with 112 after developing a load I thought was really good. Like 3 shots raged hole then a flier at 3” high left. 105 jlk same thing even though they are a really consistent bullet in my experience. Switched to 109 Berger with N555 and had better luck, but still weird stuff going on. Switched to varget and 109 and have a really nice load now I’ve shot a couple matches with Although I feel like it’s a mild load 2875 I’ll get some unexplainable pressure signs now after 2-250 rounds and only thing that fixes it is thoroughly cleaning. I think for whatever reason carbon rings are something a guy has to watch with this cartridge.
Varget is bad for carbon rings due to its high flame temp and that the charge is burned off in short length of barrel. High volume match shooting compounds this. If your reamer is a lil tight on freebore side, it comes on much quicker. Shoot with 2 guys who run dashers w/ 109s at 2880 using varget, they clean every 150 rounds, and there are definitely hard to get out carbon deposits in the freebore and first few inches after.
Clean. Clean down to steel. Borescope clean throat steel. Reshoot.
If it still doesn't shoot, I'd work up a new load.
Something changed. In your components/load or your rifle.
If it still doesn't shoot, I'd work up a new load.
Something changed. In your components/load or your rifle.
Well varget was my third powder I tried on this barrel.
N555 with 4 bullets never really had a stable load. Liked it was 99-102% fill
4350 was decent but never tried once I switched to 109’s. Still lot of room in case
Varget was my last resort because low % case fill but it was the easy button to finally make this barrel shoot. I’ll never own another hawk hill after this. Never had a bartlien this hard to get to shoot. I’ll deal with varget side effects for the next 1000 rounds and swap barrels.
Man all the HH barrels I've had(3 of em) have all shot everything pretty well. That's surprising to hear.
If you’re getting normal velocity and the “bad” ones are noticeably lower….
It’s either something up with the powder charge or your chronograph. Possibly your brass prep, but likely not for a 75 fps drop.
I’m not sure why carbon rings are being discussed for lower velocities.
Group size should be able to be reigned in via seating depth almost regardless. Unless there is something like a damaged crown or brake.
I’d hazard a guess that you’re suffering from multiple issues and not a single one.
It’s either something up with the powder charge or your chronograph. Possibly your brass prep, but likely not for a 75 fps drop.
I’m not sure why carbon rings are being discussed for lower velocities.
Group size should be able to be reigned in via seating depth almost regardless. Unless there is something like a damaged crown or brake.
I’d hazard a guess that you’re suffering from multiple issues and not a single one.
Orange targets 109 and N555 thought I had a load at “30” and then had a really bad flier in further testing.
Paper with 105 jlk written on it shooting well. Started playing with seating depth and horrible fliers as seen on third group.
White paper was 112 match burners powder charges then went to seating depth and that pic of cardboard with bike sticker as aiming point was fliers with 112.
Barrel has been very picky on seating depth. Some bullets like 109 been more forgiving but like 1.5 moa on a bad spot vs 3 moa fliers on 112 and 105 had.
Powder also made a difference getting to better SD and accuracy with varget vs N555
Same brass prep and using A&D do measure powder.
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Without having the rifle in hand, I can’t say much.
Only that I haven’t experienced any of that with any of the 10+ 6gt barrels I’ve messed with. 109 Berger, 110 atip, 112 MB, 108 Berger, and 108 eld.
I’d probably either rechamber, return, or just flat out toss a barrel in trash that acted like that. Not worth the headache.
Can’t argue with you there on headache. Probably 200-250 rounds of trying to make it shoot something consistent. Shot a Match in Kansas last weekend I can’t complain a bit how it shot with current load. One of my better personal performances over the last few years at 2 day matches. I feel like with regular maintenance I can take this barrel another 1000 rounds which it has 1050 on it right now, and then I’ll dump it. If it acts up before then I’ll pull it. Im gonna get another barrel ordered for it soon just so I have it on hand. I really like the cartridge itself although it’s been frustrating to this point I don’t think it’s the fault of the gt itself.
That’s odd because from my experience and those that I regularly shoot with the GT is one of the easiest cartridges to load for. Most shoot the 105 hybrids of 109 hybrids and those are not very jump sensitive at all. I’ve went through several barrels now and haven’t had to tweak a load yet. It’s possible you just got a crappy lot of bullets this time.
Unless on a pretty tight budget (everyone is with $5 gas now
), and even then, many times it’s cheaper to dump a barrel or just use it for practice.It’s much more common in F and BR, as many barrels aren’t capable of the precision needed. In practical shooting we are much less inclined to dump a barrel and it’s more rare. But sometimes you just get a dud.
Maybe I missed it OP, but what powder were you using? I had what looked like a good load with 112gr and StaBall in My GT go wonky and groups blew up. My theory is I may have dried out the powder too much and gotten off the node, but on the other hand, my 6.5 loads didn't go all wonky.
I've since switched to RL16, and the 112gr are shooting more consistently, but 109gr Hybrids are just better all around. 108gr ELDs were a bust though, overall this has been kind of a picky barrel, might should tomato stake it and try something else.
I've since switched to RL16, and the 112gr are shooting more consistently, but 109gr Hybrids are just better all around. 108gr ELDs were a bust though, overall this has been kind of a picky barrel, might should tomato stake it and try something else.
