Bullets going funky. Need help

screech

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I have a 375 cheytac and am loading 350gr smk over 136grains of reloader33. At 100 yards it shoots .2-.3 groups. Oh gun is topped with a 8-32nxs and the barrel is a 10.5 twist benchmark. The load has a overall deviation of around 20fps so +or- 10 fps. I brought it to 1000yards to confirm drops and I can't keep it on a 4x8 sheet of plywood. Literally. The bullets that did hit the paper made round holes so they weren't tumbling. I've been thinking it over the last couple days and am going to try a different bullet to see if maybe it's a bullet issue. If anyone has any ideas on what's happening I'd love to hear them.
 

RockyMtnMT

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The big boys put a lot of stress on bullets. The smk is known to be tough and handle the torque of the launch. My only thought is under stable from twisting out on the launch. Some twisting out but some are not and reaching the target.

Steve
 

HARPERC

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I have a .375 barrel I assumed to be 1-10" for a couple of decades. It turned out to be 1-11".

So, the question that pops in my head is, Have you verified twist personally?
 

screech

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The big boys put a lot of stress on bullets. The smk is known to be tough and handle the torque of the launch. My only thought is under stable from twisting out on the launch. Some twisting out but some are not and reaching the target.

Steve

That's kinda what I was thinking but I wasn't sure if it was possible. Have any cure ideas?
 

screech

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I have a .375 barrel I assumed to be 1-10" for a couple of decades. It turned out to be 1-11".

So, the question that pops in my head is, Have you verified twist personally?

I haven't I don't get back to the gun till September. I'll measure then. On sierras page it says it will stabilize all the way to a 12 twist. I'm going to measure when I get a chance though
 

Lefty7mmstw

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Ditch the rl33... I love the stuff but I'm having issues like that with some of my rl33 loads too. One day the load decides to shoot well, the next I can't hit the broad side of a barn with it. I have given up on 195 bergers with rl33 in my 8" twist stw and 200 grain eld-x with rl33 in my 300 rums because of this poor behavior (good days these loads were .5 to .6 moa- often better short range-- the stw was tested to 550 yards) ; the loads may be failing due to temperature issues as the poor accuracy days were often cooler than when the loads shot well...

The only rl33 load I can not make puke is 95 grains rl33, 225 hdy hpby, 215, rp brass 3.650" oal. in my 300 rum rifles. they both hold around 1/2 moa with that load no matter what...
My brother does have a good rl33 load for his 26 nos and 130 ab's....
 

RockyMtnMT

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That's kinda what I was thinking but I wasn't sure if it was possible. Have any cure ideas?

Generally I would not suspect the SMK, but it is also possible that you have some roughness in the throat that is giving the jacket enough of a beating that they aren't surviving the launch consistently. Roy was having this trouble with his 375AM. But not with SMK's. He was having bullets swap ends at about 800y. These bullets should have been fully stable on paper. We sent Roy some of our Hammers to test and all the previous problems were gone. Spinning out was has been one of our big concerns with these big horse power cartridges. The design of our PDR system has a lot of meat when fully engaged in the lands, but very light engagement with the grooves. So in the end we get the durability of the mono without the higher pressures normally associated with mono's. With our PDR design we have more meat engaging the rifling, so we don't have the worry of spinning out that plagues drive band bullets and bore riders.

Give ours a go. I think it will cure your problem.

Steve
 

Bravo 4

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My opinion but I don't think the OP has a powder issue, I would suspect a bullet issue as he has mentioned. I load RL33 in my .408 and have shot it to 2,000 yards on several occasions, both summer and winter, and not had a problem. But then again I keep my long range ammo out of the elements until ready to fire. My first thoughts are either the bullets are just on the verge of stability and some are making it or the bullets are coming apart in flight. As stated the 350 matchking is known to have tough construction so I wouldn't think they aren't coming apart with that slow a twist, and you aren't having a problem up close. I would start much closer and work my way out until I found the problem. You never know, something may have come lose on your setup or your scope took a crap on you.
I'm working on a problem child of my own and took everything off and started bare to isolate any problems.
 

screech

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Thanks guys I was planning on playing with it when I got home but I bent my decapping rod on die and so I won't have time to play again until November. I may try h50bmg. I tried the loved retumbo but once again I can't get it to shoot well. I've sadly never gotten it to shoot well. Idk I'll maybe try a different powder and see if it does it if I can get another load together. Thanks for the help fuys
 
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