Accuracy change with muzzle brake - start over with load development?

JDLawrence3

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I purchased a 338LM in December and it did not come with a brake. I developed a few loads with LRT and 300 gr A tips, and found one to be really accurate. To help with recoil, I bought an Area 419 Sidewinder brake and since putting it on, my groups have been awful. In some cases from .6 MOA to 2 MOA or worse. I have tried multiple projectiles, multiple seating depths, and multiple powders and the best I can get is 1.4 MOA. This week I shot identical rounds with h1000, with and without the brake and the groups were tighter without. Could there be something wrong with the brake? Can you over tighten it to the barrel? Should I try a different brake? Or should I just start over on my load development and hope to find something that works?
 

Taylorbok

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I have seen some do some sketchy shit but the sidewinders have been good from everything I have heard. Is your bullet possibly making contact with the brake? You can overtighten it but that would take a lot, you shouldn't need more than a bit over hand tight.
 

straightshooter1

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I purchased a 338LM in December and it did not come with a brake. I developed a few loads with LRT and 300 gr A tips, and found one to be really accurate. To help with recoil, I bought an Area 419 Sidewinder brake and since putting it on, my groups have been awful. In some cases from .6 MOA to 2 MOA or worse. I have tried multiple projectiles, multiple seating depths, and multiple powders and the best I can get is 1.4 MOA. This week I shot identical rounds with h1000, with and without the brake and the groups were tighter without. Could there be something wrong with the brake? Can you over tighten it to the barrel? Should I try a different brake? Or should I just start over on my load development and hope to find something that works?

Any time you add something that's touches the barrel you're changing the harmonics of that barrel requiring changes to your load to get back to the accuracy. You've already tried changing seating depth, but you didn't say if you changed the amount of powder beforehand. . . ???

Yes, there could be something wrong with the break and I'd try another break, like one that's the same to see if the results are any different. If the results are the same, then it's likely you need to work on the load development; though that's something that'll need to be done to some extent anyway with the change in harmonics.
 

KnowNothing256

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    I’ll second the question about bullets contacting the brake; I’ve done this to myself and it was very frustrating until I figured it out.
     

    JDLawrence3

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    Any time you add something that's touches the barrel you're changing the harmonics of that barrel requiring changes to your load to get back to the accuracy. You've already tried changing seating depth, but you didn't say if you changed the amount of powder beforehand. . . ???

    Yes, there could be something wrong with the break and I'd try another break, like one that's the same to see if the results are any different. If the results are the same, then it's likely you need to work on the load development; though that's something that'll need to be done to some extent anyway with the change in harmonics.
    Tried 4 or 5 powder charges of LRT for each bullet. Only 1 of h1000 for each bullet. (300 smk, 300 a tip, 285 eldm)
     

    RegionRat

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    Just a suggestion, when there is contact with baffles or brakes, the view from a decent borescope will tend to show it.
    Also, a piece of drill stock that slips into the muzzle will also tend to show any potential runout issues with a muzzle device.

    If at all possible, once you have eliminated the possibility of a mounting issue, borrow or try a different model and see what happens.
    Any time there is a weight added to the muzzle, you can expect some re-tune work, but your issues sounds much worse than I am used to hearing.
     

    KnowNothing256

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    I cant see anywhere where the round is touching. I'd assume I'd see brass on the brake
    It might be super faint. Here's what mine looked like when I was getting strikes, after several hundred rounds:

    246F1FF4-EF5E-4D2D-B8D8-F78E314C4D7C.jpeg
     
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    JDLawrence3

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    FWIW, I've traditionally seen a POI shift when adding/swapping muzzle devices, not groups opening up. So I'll throw my hat in the "something is contacting the bullet" crowd.
    That's what I am afraid of, however, no signs on initial inspection. Ill look again this evening
     

    Rocketmandb

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    You can always buy a different, larger brake (like for a 375) and try it out.
     

    JDLawrence3

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    Update. Still no visible marks inside the brake. I do not have a bore snake though. Wondering if a new adapter would square the brake up? I guess I'll start looking for deals on brakes because it's nowhere near as fun to shoot it without one.
     

    RegionRat

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    If at all possible, can you borrow an oversized one for a day?

    Using one of a much larger caliber would tend to eliminate a true position or runout problem from mounting error.

    If there were a gross mounting error, it should show up with a piece of drill stock with a snug sliding fit in the bore.

    If you had anything close, some fine tape wraps could help snug the fit to be able to judge the clearance in the brake.

    Maybe a piece of a cleaning rod? Even if the rod had a little rounout, spinning it would tend to show the projected bore line.

    Good Luck and in for the range report.
     

    ShtrRdy

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    You mentioned the group size being better when the brake was removed. But was it as good as before the muzzle was threaded?
     

    Mike_in_FL

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    I purchased a 338LM in December and it did not come with a brake. I developed a few loads with LRT and 300 gr A tips, and found one to be really accurate. To help with recoil, I bought an Area 419 Sidewinder brake and since putting it on, my groups have been awful. In some cases from .6 MOA to 2 MOA or worse. I have tried multiple projectiles, multiple seating depths, and multiple powders and the best I can get is 1.4 MOA. This week I shot identical rounds with h1000, with and without the brake and the groups were tighter without. Could there be something wrong with the brake? Can you over tighten it to the barrel? Should I try a different brake? Or should I just start over on my load development and hope to find something that works?


    Not saying it's the same, but read this at Post 76: https://www.snipershide.com/shootin...ac-ultra9-strike.7124761/page-2#post-10233004