Back to the drawing board?

Powder_Burns

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  • May 4, 2009
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    For those of you that run suppressed gas guns, have you had a tuned load for your rifle perform horribly once you mounted a can? I did load workup in 2020 for my .308 shooting a 155 scenar at 2726fps out of a 16” bbl, and it held pretty much 1 moa at 100. I had it doped out to 700, due to scope constraints I couldn’t do much past 800.
    August 2020 I had a concussion and didn’t shoot for 2 years. During that time I got my tax stamp and a better scope, finally went out to the range this weekend to sight in and my load is shooting closer to 4 moa now with the can installed. I put 3 boxes through the gun, got frustrated and went home. I’m suspecting that I’m either really rusty from my hiatus or the can is causing issues.

    My plan for the next trip is to dry fire a ton, and shoot for groups without the can mounted to rule out operator error, and then confirm with the can mounted.

    Do you guys have any other suggestions before I end up scrapping this load and going back to the drawing board?
     

    nn8734

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    Shooter rust and can are both factors.

    I’d plan on load redevelopment (shouldn’t take too long) as you shouldn’t be too far off with the can vs without but harmonics are sufficiently different with can mounted vs without in most cases.

    Work on dry firing as well, pay attention to reticle movements when trigger is squeezed. Watch for unintended movements, etc
     

    Powder_Burns

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    Only sad part is I got like 500 cartridges loaded, and I’m just not motivated at all to pull all those rounds.
     

    aslrookie

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    Did you not try taking off the suppressor and shooting a group?

    Correction: I read that’s your plan for next time. Without doing that, I wouldn’t even sweat it at this point. Is this a quality suppressor or a walmart special level quality?
     

    reubenski

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    I do load development with a can on. But I have switched cans on a gun and had the gun under gassed and seen accuracy deteriorate. I adjusted the gas and just watched accuracy return.
     
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    TCreedmoor

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    Someone let me try out their can at the range a couple months ago. My rounds immediately shifted 1.5 MOA to the right. Six clicks on the windage turret and it was right back to the bullseye.

    Did you tune your seating depth to find a node before seating those 500 cartridges? i.e. Did you seat the bullets to a factory ammo COAL or something specific to the harmonics of your barrel?

    Here would be my recommendation: Use an inertia bullet removing hammer, but don't remove the bullets. Just give the hammer a few whacks so the bullet slides out a bit. Then use a micrometer seater depth die and reseat bullets at several 0.003" increments. Your choice, either 0.003" increments greater than factory ammo, or starting at 0.020" short of the lands and go down in COAL in 0.003" increments. Shoot groups until you find a node that produces a tight group. Now you'll have a new COAL for shooting with the can.

    Another option would be a tuner, not sure if this one will work on your rifle, but it supposedly will allow you to attach the tuner AND a silencer.
    https://www.shortactionprecision.com/products/adaptive-tuning-system This should allow you to use your existing ammo and tune the barrel for the new harmonics.

    Please let us know how it goes.
     

    alamo5000

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    What can did you use and how did you mount it? I once knew a guy that had a Griffin can with a muzzle brake mount. He totally messed up mounting that muzzle brake so he was having wild POI shifts. Ultimately he took the brake completely off and mounted it correctly (the second time) and the problem went away.

    I also knew a guy (a different one) that bought a can with some sort of QD system. The problem was the can didn't lock up tight. It was secure in that it wouldn't come off unless he took it off, but the can would rotate under fire about 1/4th of a turn. His problem was the POI shift was actually moving around some causing bigger-ish groups.

    Odds are if the rifle shoots well without a can then it means the load is completely fine. The problem is elsewhere, most likely in the mount somewhere.

    Definitely do not jump to conclusions about it being completely a reloading issue.

    Another point to bring up is your scope can be moving around under fire. You said you bought a new optic so this is probably your prime culprit. Check ALL torque values on the optic as well as where it mounts to the gun.
     
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    wade2big

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    I don’t have a can but used my buddies on my rifles. The point of impact changed but nothing else did. This was over many rifles. It makes sense that a suppressor could mess up a good shooting combo but I haven’t seen it on thin/heavy barrels or on semi autos/bolt guns. I would need to see it to believe it.

    OP if you have the time, shoot a few groups with the can on and a few with the can off and snap some photos to post in this thread. I would like to see your results.
     

    hafejd30

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    I have yet to notice (over several rifles and several cans) accuracy deteriorated due to a can being mounted. If anything I’ve noticed better accuracy but that can be several factors including the shooter there.

    Couple things to try.

    - shoot without can
    - if shooting the same change optics
    - reseat bullets a couple thousandths
     

    ma smith

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    My money is on a bad optic or something related to it not being mounted up right.
    Get a torque wrench, and double check the pic rail, the scope rings, any muzzle break, and all the action screws, etc. Very common for it look like the ammo/accuracy is wonky, but it turns out something works lose and all goes back to normal. Also check your bipod rail and what not to eliminate there is some kind of problem anywhere in the support system.

    If you are concerned about operator influence/error, then Doing dryfire and NPA is also a very good use of time to help shake off the rust. Also, cut yourself a little slack. You took some time off, for a reason. In the same vein, it may be worth double up on hearing pro etc......just to keep all of the sound/pressure/etc from overstimulating anything.

    best of luck and hope you are healthy
     

    supercorndogs

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    Have checked to make sure the bullets didn't bond to the necks? Seat a bullet a little deeper in a loaded round, and see if you can hear it pop and break loose.
     

    supercorndogs

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    What causes this to happen?
    The cause and effects are subject to much discussion and debate. Galling, galvanic corrosion, corrosion, cold welding, does it do nothing or something, many different ideas get floated and argued about. Really the only thing that is for sure, is that they do bond to the neck somehow sometimes.
     
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