Why won't my t3 group with 75 grain AMAX's?

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prosper

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I bought this rifle SPECIFICALLY for shooting heavy VLD's. Yet, it seems to only really like the 52 grain weights :(

Edit - the barrel is marked 8" twist

I've tried new brass, fireformed & collet sized brass, rem match primers Winchester primers, varying COLS up to and including jammed into the lands. I've tried Varget (24-26 grains) and 322 (21-23 grains), both proven performers in this combination.

Yet I can't group better than 3" with the 75's, ever. Every shot is a flyer, with every charge weight. This is especially frustrating as I can shoot .3 groups with the 52 Hornady and Nosler BTHP', and 52 AMAX's using these same primers, powders and cases.

What's going on here?


EDIT:
Well, I've managed to get some 1/2 MOA groups at 200 yards now. After trying Varget, benchmark, 4064 and 322, as well as Rem 7 1/2, WSR, fed SR match and cci 450 SRM primers. Switching to Magnum primers made most of the difference, and doing load work in two tenth grain increments was absolutely necessary. With a light sporter barrel, charge differences of only two tenths made considerable differences. Now to do some chrony work; 25.0 grains of Varget, 23.5 of benchmark and 24.5 of 4064 all produce similar groups, so whichever is fastest wins
 
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Can you measure the twist rate? Would be a real bummer if a 12 twist was installed in your rifle.

If the twist is correct, take apart your seating die. Put the Amax into the seating stem and see if the nose of the bullet bottoms out on the seater plug before the ogive is supported by the plug.

A very common problem as the depth of most seater plugs are designed for stubby bullets. If it does, just drill out the plug so the bullet can go in further. Do not change the angle at the bottom of the plug as you need that to contact the ogive. you can use a drill press if you are careful to line things up straight.

I just picked up a Forster seater for my 300RUM which I hoped would account for very long bullets. NOPE. The 208gr Amax hit the top of the plug long before the ogive is supported. End result enormous variations in bullet runout and really crappy groups.

This is a very common problem.

Jerry
 
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Double check your twist with a cleaning rod and a patch. the rod should turn as it is pushed down the barrel, put a mark on it and count the revelutions as it is pushed down the tube.
 
Try other VLDs. Sometimes rifles can be picky about bullets, particularly with VLDs. Try some Sierras, etc., or different makes of 80s. Also worth experimenting with 68/69/70s.
FWIW some .308 target rifles shoot very accurately with Sierra/Nosler/Amax 155s, but just don't do well with 154 Lapua Scenars.
 
tiriaq said:
Try other VLDs. Sometimes rifles can be picky about bullets, particularly with VLDs. Try some Sierras, etc., or different makes of 80s. Also worth experimenting with 68/69/70s.
FWIW some .308 target rifles shoot very accurately with Sierra/Nosler/Amax 155s, but just don't do well with 154 Lapua Scenars.
Click to expand...

Yeah, I have other rifles that have particular tastes when it comes to bullets. But the difference is usually 1-1.5 inches vs .5 inches, not 3 inches vs .5 inches.

You're right though, I'll try another bullet. I think the 80 grain amax has a standard ogive (as opposed to a VLD), maybe I'll try it next Ideally, I'd like to stick with the AMAX as its plastic tip and thin jacket should make for a good LR varmint bullet where a MatchKing probably wouldn't expand or fragment on impact
 
Why would I sell it cheap? I have 4 5-shot targets under .4" with the 52 grainers (all 4 with different charge weights. Out of a total of 6 tested with these bullets) :D
 
I have no need for a 1/2" 52 grain gun, I've already got one in my 222. I'm not saying my Tikka isn't a good gun, just that I'm after a 75 or 80 grain AMAX shooter, and it doesn't appear that this is one.

I've still got a few more things to try before I give up on it though
 
75Amax

Strange, my SS T3 shoots the 75Amax as well as it shoots the 55Vmax, very well. Haven't stretched out past 1oo yards though.

How far off of the rifling did you seat the Amax? I started at .020. Makes for a long little round.:)Do you single feed your Amax loads?
 
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