Muzzle Break causing feeing issues? Update

[rockchalk06]

What's makes you think it's over gassed? Not arguing, just not thinking this is the case. Brass ejection seems standard 3-5 o'clock 4 feet away or so.

 

[JEVapa]

What's makes you think it's over gassed? Not arguing, just not thinking this is the case. Brass ejection seems standard 3-5 o'clock 4 feet away or so.

I don't think it is. I also don't think it isn't. It's just one possibility that should be eliminated from the problem list. You can do this via the assessment I and @HiredHand described.

I don't regard the brass ejection pattern as a final determination that it's an over/under/correctly gassed system. It's just landing to the right rear somewhere.
Overgassed guns will many times override the cartridges in a magazine and will appear that it is shortstroking. You just want to eliminate the possibility. It will usually be accompanied by doublefeeds and other malfunctions.

There is a litany of things you can do to find out what the problem is but, on a forum, it's all guessing and throwing stuff at a wall and hoping something sticks. Usually, you need another human watching what's going on while the other shoots.

I will throw you an offer though. You can come out to my place and we'll get it solved in a few hours. Have a 100m pool table flat range in a bowl, plus an extra few hundred meters around it. Bring your gun, ammo and mags and whatever it is you shoot with. Lemme know via PM.

 

[HiredHand]

@rockchalk06 re: Gunbuffers comment about ambient temp. I think he’s on to something concerning your reloads.

 

[JEVapa]

I'm on the low side at 19.5 grains, but pushing about 2350 FPS.

I missed this completely in your first post. These should be moving around 2750 FPS min in an 18" barrel. With the ambient temp comment, it makes more sense now.

Your speed is slower than almost all minimums on Load Data or Hodgdons. Should be well over 2450 min and closer to 2500+.

What powder?

I also revoke all I said before except the offer...I don't think it's mechanical or gun setup centric. I think it's your ammo. I have some MK262 you can try; it runs 2790 in my MK12.

 

[rockchalk06]

@rockchalk06 re: Gunbuffers comment about ambient temp. I think he’s on to something concerning your reloads.

That's a good point. I shot those originally over my Chrono at 78° with the A2. I just thought N135 would be less temp sensitive than this.

I did make a note that my dope changed at 300 today vs 78°. 78° had 1.9 MRAD and today I had to dial up to 2.1 to get the same impact.

Maybe a combination of lower temp and the break combined? Either way, I'll change back to the A2 and run some M855 through it.

If it's my loads on the weaker side, I'm kinda bummed. This lighter load produced the best group and best SD all the way up to 2600 FPS.

 

[rockchalk06]

I don't think it is. I also don't think it isn't. It's just one possibility that should be eliminated from the problem list. You can do this via the assessment I and @HiredHand described.

I don't regard the brass ejection pattern as a final determination that it's an over/under/correctly gassed system. It's just landing to the right rear somewhere.
Overgassed guns will many times override the cartridges in a magazine and will appear that it is shortstroking. You just want to eliminate the possibility. It will usually be accompanied by doublefeeds and other malfunctions.

There is a litany of things you can do to find out what the problem is but, on a forum, it's all guessing and throwing stuff at a wall and hoping something sticks. Usually, you need another human watching what's going on while the other shoots.

I will throw you an offer though. You can come out to my place and we'll get it solved in a few hours. Have a 100m pool table flat range in a bowl, plus an extra few hundred meters around it. Bring your gun, ammo and mags and whatever it is you shoot with. Lemme know via PM.

I appreciate the offer. I'll try a few things first and if that doesn't work, I will hit you up.

 

[jackary]

What buffer are you running in it?

 

[HiredHand]

That's a good point. I shot those originally over my Chrono at 78° with the A2. I just thought N135 would be less temp sensitive than this.

I did make a note that my dope changed at 300 today vs 78°. 78° had 1.9 MRAD and today I had to dial up to 2.1 to get the same impact.

Maybe a combination of lower temp and the break combined? Either way, I'll change back to the A2 and run some M855 through it.

If it's my loads on the weaker side, I'm kinda bummed. This lighter load produced the best group and best SD all the way up to 2600 FPS.

I’d shoot the M855 before changing back to the A2. You want to eliminate variables not create more.

 

[HiredHand]

What buffer are you running in it?

OP mentioned he was running a Rifle buffer and spring.

 

[rockchalk06]

I missed this completely in your first post. These should be moving around 2750 FPS min in an 18" barrel. With the ambient temp comment, it makes more sense now.

Your speed is slower than almost all minimums on Load Data or Hodgdons. Should be well over 2450 min and closer to 2500+.

What powder?

I also revoke all I said before except the offer...I don't it's mechanical or gun setup centric. I think it's your ammo. I have some MK262 you can try; it runs 2790 in my MK12.

N135.