please help diagnose my issue

[turnbull]

My understanding is that rifle uppers work ok on carbine lowers, but the opposite you can be "under buffered" due to the more violent gas action.

I've shot 20" rifle gas system grendel on M4 lowers with no problems. But from dialog here, most Grendels are on the high side of gassing anyway.

Don't know where you got the idea that .223 operates at higher pressure then Grendel, that's not my understanding.

I'd deal with the ramps first, as you know that's wrong.

But over buffering can also cause short stroking as I understand it. (But I'll defer to the input of others). I'd sure see if I could borrow a known good rifle lower to try to look for a behavior change. If it does the same with that it's almost certainly an upper problem.

If you have a removable gas block, You can visually inspect the port, gas tube, etc. If it's a pinned forged base, there are some things you can try. One being to use air pressure into the gas tube (gently) to blow out your gas system. You'll be able to tell if the port is unclogged.

There are proper sizes for the gas port. If you have a removable gas block you can determine that. If not, I'd workout the feed ramp issues first.

The only difference as I understand it in the Grendel vs .223 gas systems is the port size in the barrel. The gas blocks, gas tube, etc are all the same.

Well i've read that .223 is around 55k psi, and the max Grendel loads (as posted by Hodgdon) is right around 50k psi. Plus it may have been a 5.56 upper, and 5.56 is around 62k psi. Don't exactly remember which one he said it was. I don't see why the port would be clogged if the rifle is brand new though, but if what you're saying about the port size is true, then that may be my problem, because I know he said that they just drilled out a .223 (or 5.56) barrel, so they may not have altered the port size.

[mtn_shooter]

Check out your gas system. Look for a misaligned gas block/fsb, messed up gas rings on bolt, loose or blocked carrier key (tube ontop of bolt carrier). If all of that is set, try a box of hornady or AA ammo. Wolf may be under powered for your rifle. I know it runs about 75fps slower than my handloads in my rifle.

As to your handloads, very small poowder charge. I don't start at minimum loads, generally 2-3gr below max and work up from there.

The only difference between 556 and 6.5 rifles is the bolt, barrel, and mags. Everything else is standard and should work with eachother.

[Darkop]

Put ONE (1) round in the magazine and shoot it. Does the BCG lock back ? Where is your ejected/extracted case landing. If it doesn't lock back, check your magazine spring first then your gas system second. Pull your hand guards and see if you have any gas leakage as identified my carbon or soot at connection points.

Until that day,
Darkop

[longdayjake]

Now that you are saying that this happens with factory ammo too, you need to check your gas rings. Make sure they are not all lined up or make sure none are missing. You have a gas leak somewhere. May be in your gas block, or may be in your gas tube. You are losing pressure somewhere.

[sneaky one]

When I first shot my Grrr. 3 yrs. ago I had the same issues, Some were traced to underloading,, and we found 1 more problem.... inside the ejector hole, about half way down was a giant burr that limited the spring travel to about half. We found the correct size drill bit (pays to have 600 on hand!) and hand reamed the burr out easily. Yes These guns are overgassed, the manufact. want to sell you a functional weapon,, I guess it's up to oneself to fix many of the small flaws on the AR platform. Many soldiers died in nam cuz of this gun, sad, but it can be made better now days.

[warped]

By the time the issued weapons were M16A1 the problems were largely gone.

Over gassed is good when you work in a dirty environment and the operating system is full of shit.

Or a nearly frozen weapon, I know that one for a fact.