Originally Posted By Dano523:
Need to see photo's of your sent cases, both the sides of cases and the spent primers as well.


next, do not use the mag as either a hold point, or as a bipod off the bench, since will cause mag to tilt in well and cause problems. Brass isn't dented.

Last one, when loading mags, make sure to rasp back of mag off your palm or some other surface, to make sure that all the rounds in the mag are seated all the way back with rims tight against back of mag.  During firing, the rounds will be kept to rear of mag.

As for charging, either pull CH all the way back and let it go, or lock B/C on catch, the hit catch so B/C is running full speed to strip/load/ock the bolt home.  Hence do not ride the charging handle forward, and if you do, then will need to use the forward assist to lock the bolt all the way home.

As for failure for mag release to raise the bolt catch to lock the bolt back on last round fired,
Shotgun upper open, insert empty mag in well with it follower pushed forward in mag body, then push back of mag forward in well while holding bolt catch down, then release mag catch to make sure that back of mag follower is able to push the mag catch back up.
Don't have this happening,
http://80percents.com/images/thumbs/m1_machining_lower_bolt_catch.jpg

Next, if follower is lifting mag catch up, make sure it lifting is all the way to the stop.  If it seems that the catch is not coming all the way up, then may have to pull the catch to check the detent spring channel, since may have debris in it, that is causing the spring to have more tension that needed to keep it down. Also point out, brand new mags, and mags that have  seen say 20 reloads, they need to be pulled all the way down, to be CLP cleaned inside and out of all the mag parts.

From here, pull all the way back of the charging handle, and make sure that face of the bolt stops 1/8"~1/4" in front of the back edge of the ejection port, and the last inch of  pull of the CH is the same tension as the middle of charging handle pull.  If rear of pull seem harder, then could be problem with recoil spring, or could be problem with hammer binding in the FCG when carrier comes all the way back.

from there, spent cases should be ejected a clean 5-10' out of the ejection port on a reaward path (before striking the upper defector) and if spent cases are dribbling out, then time to check for leaks or blockages that may be causing the problem in the first place.  
Note, metal expands when it gets hot, so rig may be boarder line colds, but a few round through the rig to heat the metal up, and could be why the gas leak problem is only happening then.

As for LWRC, get them on the phone again, since does sound like rig does need to go back to them again, ,and they should be refunding any funds that you had to pay for the first time around.  Hence without chucking lawn darts in the neibors yard blindly/nothing is binding up, problem could be as simple at gas leak between the key to top of carrier.

Originally Posted By Dano523:
Describe what solutions/methods you are using to clean the rig/mags,
and what solvents you are using to lube the bearing areas of the rig once they have been cleaned correctly, and the rig is being put back together.

Originally Posted By cjcutter:
Balistol, bore snake, Tuff cloth Sentry.

Originally Posted By Dano523:



Switch over CLP (either breakfreeCLP or RADCOLUBE CLP if you want to buy it in the gallon or larger containers) ditch the bore snake, and go back to solid one piece cleaning rod with brass brushes, patch jig, and chamber brush),

https://www.amazon.com/Lubricates-Preserves-Military-Grade-Revolutionary-Must-Have/dp/B073RNR8XR

And will bank that problems go away once you have removed the old Balistol (that has parfin wax in it that is causing problems) from the rig.
To point out, do not use Hoppers solvents to clean the rig either, since it leaves being a protective layer that will cause the rig to foul choke out very quickly too (plus does not mix well with CLP, and the mess that those two mixed leave behind, even faster fouling choke out of the rig)

If you want to make clearing  the rig faster (bore fouling), then add Sweats copper solvent as your first cleaning agent, to first clean the copper out of the bore, get all that out until patches are not longer coming out blue, but dry, switch over to chamber brush with CLP to get chamber clean, push that mess out to the muzzle until patches come out dry, then CLP for the fouling of the other parts of the rig, get all the fouled CLP out, then light coat of fresh CLP on the upper bearing parts, including light coat of the buffer and recoil spring, and outside and in of the B/C before it installed into the upper.

Hence truth be told, does sound like the rigs problems, could be solved at the range with a can of BreakfreeCLP to give it bearing areas a fresh coat of the correct lube in the first place.  Hence with breaking the rig in, when you get to the range, pull the B/C to give it a fresh light coat of CLP inside and out, before you start shooting for the day.  the Fresh CLP on it, will transfer to the rest of the bearing surfaces, to combat the fouling to slow its build up down.

Originally Posted By Dano523:
If rig is over gasses, then spent cases should have the rims bent back from the extractor pull to start with.

So lets take this back to the beginning, with photo of spent case, cleaned chamber and photo's of it to make sure camber is not reamer ringed to hell, and even checking the head space and leade (to make sure bullets are not embedding on loading) with head space gauges.

Simply put, if its taking all that to get slow the unlock back to normal with standard 223 ammo with the barrel gas port over sized, you stand no chance in hell of trying to get the rig to run with Mk262 ammo instead.  And I bring that up, since barrel is 1/7 twist, so not going to shoot the tightest with 55 gr, maybe with 62gr that will work in 1/8 twist barrels, and will really want 69gr or heaver bullet to print is best.

Originally Posted By Dano523:
Again, if rig is over gassed, meaning bolt unlocking to soon with the residual pressure on the bore too high/the spent case still over pressure locked to chamber walls, to cause bolt/extractor to have one hell of a time trying to get the spent case out that is slowing way down the rear stroke of the B/C, then extractor should be bending the hell out of the case rim on the pull.

Or, chamber conditions are less than stellar, if bolt is unlocking at correct timing, but side walls of chamber are not cleanly releasing the spent case as the residual pressure in the bore has dropped on pull for what should be a clean release of the spent case from chamber walls.

https://www.lwrci.com/IC-DI-Standard-556_p_246.html#mz-expanded-view-1448543813416

Bottom line, if barrel gas port is correct, then should be no reason anything more than standard carbine buffer and standard carbine spring in the rig for the rig to run correctly.  The reason that the M-4 runs the H  buffers (H3 when  older higher blow back supressor are in play), and the Colt extra tension extractor spring, is Mk-262 ammo uses slowing burning power, which pushes the peak spike of the powder burn closer to the barrel gas port, this speeds up the bolt unlock timing, and the heaver buffer slows the unlock back down to normal, the extra tension extractor spring, makes sure that spent case is not dropped from the bolt face on the pull.

So again, if your having to throw that much buffer weight and even stronger buffer spring at the rig to get it to run correct with comercial 55gr  55K psi ammo, and have the last round hold open work correctly its got problems.  It does sound like the stroke may be correct, and the problem more of bolt hold open spring/its channel to shallow in the lower receiver, and the weight of the heaver buffer is causing more rig jarring at back of stroke (more felt recoil), which is allowing the bolt catch more time to be raise by the mag followers in the end.



So here is a set of lower drawing that you an download if you want to see if catch spring channel is drilled deep enough/wide enough in the lower.
Note, bolt catch detent should drop freely in to the channel as well.
https://cdn.shopify.com/s/files/1/1067/2310/files/AR15_Lower_receiver_blueprint.pdf?3587052860788957110

Pull the bolt catch, and using a 5/16 drill bit by hand, clean up the bolt catch spring channel in the lower, and double check the depth of channel to make sure it deep enough as well.  Also, make sure that bolt catch is not binding in the slot for it in the lower as well.

______
And again, although  you can shoot 55gr ammo through a 1/7, it not going to print its best.  So may want to look into some 62gr ammo, or start to reload 69gr ammo instead.  And with the spent cases rims not being bent, the bolt stops correctly on CH pull and not increase in tension from buffer spring binding, don't see the problem as bolt unlocking too soon, but problem with either bolt catch binding, its spring too strong/its channel not drilled deep enough, and why some of the mag spring and followers, are not able to get the catch up fast enough to stop the bolt on last round fired (if mag springs are still in spec), and the heaver buffers just causing more felt recoil, more jarring of the rifle at back of stroke, while is helping the mag springs get the catch up in time to catch the bolt on the way back forward.

Ot,   if the problem really is the barrel gas port too large, the rig is over functioning with bolt unlock too advance with standard carbine spring and buffer with the 55gr ammo from too much gas from gas port, then rig needs to go back, to have the barrel replaced (with a barrel that does have correct size gas port instead).  As stated, barrel is 1/7 twist, designed to stabilize 69gr ammo, and that ammo uses slower burning power, and it going to cause even more pressure through the barrel gas port, to make the bolt unlock even faster.

Originally Posted By Dano523:
If you have another ar15, or know of someone with one, then double check your bolt catch pressure to raise it, against the other rig.

As stated, does not seem like the rig is over functioning since not getting bent rims, but isntead the extra mass of the buffer and spring, is making the rifle have more felt recoil to Jar is more as the buffer slams off the back wall of the receiver extension void, which may be helping to get the bolt catch up, before the bolt starts moving forward over it again.