I have Phantom 7.62 that I use on several hosts from .223-30/06. All have some shift but very repeatable and accurate. My problem is I just got an AR with a 18" Lilja barrel that shoots decent without the suppressor and decent with the suppressor but the shift is stange. At 100 yds the shift is 0.5 mils low and as is usual I dial my dope for a given range and the add the shift for the can. So for this load I am 0.4 mils at 200 and add the 0.5 mils for the shift of the can for 0.9 mils.......and it shoots nearly 1.5 mils low. So it is shifting almost 2.0 mils at 200yds. I find no evidence of baffle strikes and grouping is good but the increase of shift low vs the recorded 100 yd shift is killing me. On every other platform any recorded shift from the can at 100 has been consistent out to 800-1000 yds. Is it possible to just have a set up that the can is just not going to work due to harmonics? This is the smallest contour barrel I have used the Phantom on and it is heavy. Any ideas where to go from here with this rifle?
Suppressors Shift problem/question
- Thread starter ggmanning
- Start date
Re: Shift problem/question
I am by no means an expert and the following only represents my opinion but something does not sound right. There are only a few things that affect the projectile after it leaves the barrel. Assuming there is no massive keyholing/destabilization (which you say there is no evidence of), the impact at distance is a function of MV and BC - and that's about it. I would re-confirm the correction needed at 100 yds. If your suppressed 100yd zero is accurate there is nothing besides MV and BC that will affect your impact (elevation-wise of course).
Because I do not know exactly what you are using I would recommend the following:
- check ammo and use a load or factory ammo which you are familiar with its muzzle velocity (some people use subs or different loads with their cans and you did not specify)
- re-zero at 100yds (suppressed of course) and look for keyholing
- use your dope/calculator to dial in for your distance shot
Besides that there should not be any possible reason. Put simply, if all the above are accounted for there is no physical way for a bullet to drop that much over 100yds.
More senior members please enlighten me if I am way off....
I am by no means an expert and the following only represents my opinion but something does not sound right. There are only a few things that affect the projectile after it leaves the barrel. Assuming there is no massive keyholing/destabilization (which you say there is no evidence of), the impact at distance is a function of MV and BC - and that's about it. I would re-confirm the correction needed at 100 yds. If your suppressed 100yd zero is accurate there is nothing besides MV and BC that will affect your impact (elevation-wise of course).
Because I do not know exactly what you are using I would recommend the following:
- check ammo and use a load or factory ammo which you are familiar with its muzzle velocity (some people use subs or different loads with their cans and you did not specify)
- re-zero at 100yds (suppressed of course) and look for keyholing
- use your dope/calculator to dial in for your distance shot
Besides that there should not be any possible reason. Put simply, if all the above are accounted for there is no physical way for a bullet to drop that much over 100yds.
More senior members please enlighten me if I am way off....
Re: Shift problem/question
Thanks, been through all my check list....that is why it has been frustrating as it defies all my experiences with my guns and the can. I am shooting factory SW ammunition match loads 77 SMK.....the only gun I shoot factory loads. My dope is right on and chronographed with my ballistic calculator and all pertinent barometrics. I figured it had to be misaligned so I used another QD mount and same issue. The barrel is factory threaded by LIlja so I would expect it to be right on but.......could be the issue. Since the can is 7.62 it would have to be off a good bit for a strike but could be off center enough to not strike a baffle but still cause issues. Looks like I may just have to pull the barrel and indicate the threads on a lathe to check them for run out/concentricity.
Thanks, been through all my check list....that is why it has been frustrating as it defies all my experiences with my guns and the can. I am shooting factory SW ammunition match loads 77 SMK.....the only gun I shoot factory loads. My dope is right on and chronographed with my ballistic calculator and all pertinent barometrics. I figured it had to be misaligned so I used another QD mount and same issue. The barrel is factory threaded by LIlja so I would expect it to be right on but.......could be the issue. Since the can is 7.62 it would have to be off a good bit for a strike but could be off center enough to not strike a baffle but still cause issues. Looks like I may just have to pull the barrel and indicate the threads on a lathe to check them for run out/concentricity.
Re: Shift problem/question
Is your AR a piston action? Used my can on a Rock River and it was great; used on a Ruger and was putting them in the dirt as the can heated up. Changed gas setting and is spot on now. I know dumb mistake but I'm still a rookie.
Is your AR a piston action? Used my can on a Rock River and it was great; used on a Ruger and was putting them in the dirt as the can heated up. Changed gas setting and is spot on now. I know dumb mistake but I'm still a rookie.
Re: Shift problem/question
This one is DI. The can no problem on 2 other piston AR's. Good thought though.
This one is DI. The can no problem on 2 other piston AR's. Good thought though.
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