243 win /115 Dtacs

codym

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Looking to re-work a load for my .243 win.

I was running 110 SMKs @3080 with lapua brass and h4350 br2 primers, but I’m struggling to keep them in that node without pressure.

I have 500 coated Dtacs that I want to finish the barrel off with. I have h4350 and h1000. I’m hoping to get these to shoot around 2950-3k. Any suggestions on a starting point. I was at 39.6 with the 110’s so thinking about starting at 38 gns with the dtacs and working my way up.
 

ShootnFool8

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38.9 gr - H4350
26" Proof Barrel
MV - 2858
Don't knw if that helps you any. But might just give you an idea. Also that's with 1000 rounds down the barrel.
 

codym

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No that is super helpful. Where did you find pressure? I hear people running in the 40 plus area with the 243 and h4350 and I come no where near that without cratered primers, ejector swipe and losing primer pockets after one or two firings.
 

ShootnFool8

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No pressure signs what so ever. I was running 3113 MV when I first started shooting it. Still no pressure signs. Not sure what my grains was at. Not home to look up. But that was with 105 Berger's. I changed to DTACS about 400 hundred rounds into barrel.
 

codym

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I’m running a criterion 7.5 twist at 26’ I’m also about 4K above sea level so I think they should be fine. I have about 700 rounds on the barrel, gonna be toast after these next 500 then I’m going to a 6br and 105 Berger’s. Give up some bc/speed but hopefully much better consistency and barrel life.
 

TACC

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Great info, these are all out of bolt guns not semis correct.
 

6brshooter

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Cody, are you getting a carbon ring? Do you remember what my load was in that barrel with win brass? Criterion uses a .236 bore, they run a little faster than the .237 bore.
 

RogueTanker

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What brass are you running on that load, is it close to max in your rifle? I really like h1000 for temp stability but haven’t messed with it in a 243

Whole bunch of resized PPU 7mm-08 brass.

Loaded that short gives me a lot of crunch and slightly rounded primers. It seems you run out of space before pressure hits.
 

codym

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No I’ve scrubbed it really well the last few hundred rounds. You were using 42.2 of h4350 but I could never get close to that with Lapua or nosler brass, I think you were using Winchester brass right? I’ve ran it pretty hard trying to get ready for matches in 100 degree temps. I just can’t keep velocities consistent or get rid of fliers with the smks. I think I just need to start over. I know I’m chasing the lands a bit now, so I’m hoping the dtacs will do better with some jump. I see the loads people are running in 243’s and 6 creeds and I can’t get anywhere close without getting pressure, was hitting 3080 but very inconsistent Es and sd’s.
 

6brshooter

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H4831SC works really well in 243, 43.0-43.5 worked good with heavy bullets. Not super fast, about 3k, but unreal accuracy and single digit sd/es over 10rd strings.
 

codym

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I have 4831sc for my 280ai, I may give it a try as well. I’m not trying to play the speed game at all, for me I just want super consistent load to work off of. I would be ecstatic with a 2900-3k load with the 110’s or 115’s that I could keep a low sd and Es in hot weather That I don’t have to keep dicking with.
 

codym

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I don’t have retumbo . This weekend I will run some pressure tests with h4350 and h1000. I’m gonna start at 37 gns for 4350 and 45 gns of h1000. I will report back.
 

codym

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That’s the fun, but hard part of these 6mm’s. So many good bullets! I have Berger 105’s and 108’s that I’m sure would shoot really well too. That’s a hell of a nice group
 

RogueTanker

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Went back and shot some more and noticed the following all at 46.2gr h1000:

Coated DTACs
PPU brass ran at 2956, no ejection issues, same with sig brass, but about 75fps slower.

Non coated, new lot
PPU brass was getting really tough to eject. Rounded primers though still. Sig brass, smooth and no issues. About 85fps slower.
 

codym

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I’m assuming that the PPU brass probably has more volume than the Lapua or Nosler brass, I believe the Winchester brass does but never measured just weighed a few.
 

codym

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I ran 37-39.1 of h4350. Stopped at 2984 with 39.1 without pressure. I'm gonna push up to at least 40 gns. I would really like to shot these around 3000 fps. I shot the ladder at 400 yards and the entire group was sub moa. first 5 shot sighter group was at 37 at .5 moa. I'm really liking these bullets so far.
 

Iamero

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Just ran 39.0 and 39.5 H4350 for my first two loads. I wasn’t extremely steady for the 39.0 but it still grouped well. 39.5 was an outstanding group but had slightly cratered primers and POI shift vertically about .5 Mil.

Would you recommend backing down to the 39.0 and playing with OAL to dial that load down? Haven’t run it over a chrono but if it produces 2950+ then I’ll be happy.
 

codym

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I would, but I shoot in super warm weather in NM. I have a problem with pressure spikes when it’s over a hundred and I’m loading close to max with 4350. I was well over 2900 with 39 grns. I’m running a 26’ barrel with a little longer throat. I’m gonna work up until I find pressure this weekend but I think I’m gonna end up around that 39 grain neighborhood as well.
 
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Iamero

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Yea it was 73 degrees today and usually only gets over 90 a few times a year here in MI so I don’t have a drastic temp spike but usually enough to over-pressure a near max load. Might back it down to 39 and run that on the chrono to see where its sitting.