Ejector swipes

[flyfisherman246]

I just put together a dpms pattern ar10. 16" .308 with rifle length gas system and .096 gas port. Adjustable gas block set just open enough to cycle. I'm using an lmt mws buffer kit which has an h3 buffer and a5 length tube. It has an aero precision nitrided bcg with high pressure firing pin and hole. This thing is destroying brass. Horrible ejector swipes. The primers look fine though.

I also have an lmt mws with a custom 16" .308 with rifle length gas system and adjustable gas block, and this thing is perfectly fine on brass.

I tried the lmt bcg in the problem rifle (after checking headspace) and there was no ejector swipes. The brass looked fine. What could the aero precision bcg be doing to cause these issues?

I have heard of people having these kind of issues with 6 and 6.5 creedmoores or having really long barrels with short gas systems. Or light bcg and buffers. But I should have the best of all worlds here, short barrel and long gas system, full mass bcg, adjustable gas block, and h3 buffer.

Any ideas? Thanks

 

[CNJarvis]

I had a similar problem with mine. 260 Rem with a standard weight BC, spring and buffer with a Rifle+2” gas tube and a Superlative AGB. No amount of gas bleed-off would cure it, so I wound up adding 3 tungsten buffer weights, which in combination with some gas block adjustment, has mostly solved the problem and cases are ejecting at about 4 o’clock. I still need to play with the gas block a bit. You might try adding another tungsten weight and retuning the gas block to see if that helps.

 

[Ravenworks]

I had the same problem with an Aero build.
Make sure you run the bolt WET WET WET.
Everything calmed down after 40 or so rounds through it, the BCG was really tight.
I have six Aero precision BCG and every one of them are tight.

 

[Fishin6061]

On a 6.5CM, an adjustable gas block like the SLR helps greatly.

 

[ssdrew]

I feel like I have read about this issue with aero bolts. It was a while back, so I'm not sure...I know that helps a lot ?...did you try the aero bolt and bcg in the lmt to see if the issue followed? Maybe try the lmt bolt in the aero bcg. I would try to narrow it down the the specific part.

 

[Fishin6061]

Had swipes with my Larue factory fun

 

[j-dubya]

Just read that you had an LMT bolt carrier group in there. Your gas port, LMT bolt carrier, and buffer weight with the adjustable gas is a very successful combo. I use an H2, but have also gotten away with a regular H buffer too when dialing down the gas block. While I am using Knight’s buffer springs, there shouldn’t be too much of a difference from the LMT, if any. Unless your is worn.

Your other brand carrier’s weight is the culprit. Compare it with your LMT on a scale. That or they have a different cam pin pathway. But your recipe with the LMT bolt group should be minimal gas adjustment to get it right, especially with an H3.

 

[newguy2k3v2]

The bolt itself can make a difference. I have a older lmt mws that had the gen 1 single ejector bolt and I got ejector swipes with EVERYTHING. Occasional FTE as well. Swapped to the newer dual ejector bolt and it's a night and day difference. No swipes with the same loads.