AR feed problems...

[rushthezeppelin]

Was out at BOTW today with Breakingcontact and after my first mag which went clean I started having feeding issues. No ejection issues at all, rounds seemed to spit out the normal 10'-15' but either it wasn't stripping a round off the mag at all or it would jam them bullet up into the locking lug area of my barrel marring up the rounds pretty badly. It started out every five rounds or so but once I got to about 5 or 6 mags in it was doing one or the other problem on every shot. Tried eliminating mag problems, tried 4 different Pmags 2 gens 3s and 2 gen 2s and even a GI that BC let me borrow. Went and traded some 556 with one of the guys in the other bays and same problem. I had just switched from an A2 birdcage to a Miculek brake and tried switching back to the birdcage, same problems. Talked to Eric in the shop and he suggested it was either a problem with the gas system (which he wasn't sure of as he says usually you get ejection issues with that as well) or a dirty buffer tube.

Got home and inspected the buffer tube which I've never cleaned but it seemed to have almost no carbon at all just a light film of cold, gunky (but clean) frog lube which should have warmed and slicked up I would think. Then I ran a pipe cleaner with some frog lube through the gas key which didn't seem insanely dirty certainly not blocked up and it dawned on me that I haven't put the obligatory drop of lube in the gas key in at least 500 rounds (gun is around 1200-1300 round count and only ever had problems with a bit of steel I put through it around 1k). Could that lack of lube in my gas key have caused the cycling issues? If not any other ideas as to what could be causing this? As Breakingcontact can attest to, everything else on my bolt was properly lubed up. Could it have been the cold sludgy frog lube in the buffer tube? Would it even warm up enough in there to get it slick, which could explain why it was fine for the first mag while it was still warm from the car but after leaving it on the bench and shooting a few mags out of my pistol and coming back it was cold and sludgy and never warmed up?

Need some ideas here, want to get my trusty DPMS back into the HD rotation instead of relying solely on my 9mm.

 

[Shorts]

Short stroking? Can you get specific on the ammo used? Buffer weight & spring?

Any way to try a different lower on that upper to rule out any dimensional issues in the magwell?

If you didn't get a chance to run it well lubed, would be worth knowing though.

On the gas key, BCG and tube, does the BCG slide smoothly when it closes up and opens? I have read of slightly off center gas tubes that cause just enough friction o the gas key to bind it up.

 

[9x19]

Doesn't a short-stroke usually result in an ejection issue?

Since extraction and ejection were normal, and if the BCG was lubed properly, then it almost has to be the gunky lube in the buffer tube, slowing the return stroke. That buffer tube spring's main job is returning the bolt to battery.

Good luck.

 

[rushthezeppelin]

Short stroking? Can you get specific on the ammo used? Buffer weight & spring?

Any way to try a different lower on that upper to rule out any dimensional issues in the magwell?

If you didn't get a chance to run it well lubed, would be worth knowing though.

On the gas key, BCG and tube, does the BCG slide smoothly when it closes up and opens? I have read of slightly off center gas tubes that cause just enough friction o the gas key to bind it up.

Ammo was AE 223 for almost all of it and about 5 Independence 556 that I traded for at the end of my day. Buffer weight and spring are I assume standard milspec, w/e comes with the DPMS Oracle.

As to a different lower, BC was a dummy and decided not to bring his AR :P otherwise I would have had a control to test against on that. As far as I know the mags sit just the same as they always have in my lower and would feed perfectly fine when inserting a new mag and hitting my bolt release.

Didn't get a chance to run it with lube in the gas key as my dumbass left my froglube at home. BC offered some of his Mpro7 but I've heard of bad things happening when mixing FL with any other petroleum based lubes.

As to the tube alignment everything seems to be fine although I did switch gas blocks not too long ago to put a FF tube on. It doesn't seem to be off and ran fine for at least 200 rounds after the change and before today. Granted it is a little hard to tell since if its off since I'm feeling the bolt turn in the carrier (took upper off lower and am pulling in and out on the back of the carrier). Might loosen the gas block and to try and see if I can get it to feel any different.

 

[Vaquero]

Gunk.

 

[rushthezeppelin]

I think I'm going to probably end up degreasing my buffer tube and just using a slick when cold lube then. Ohhh shoot I almost forgot to mention I've been having problems with bolt lockback for quite a while. At first it was just with my thermold 20s and then it started happening more and more with my pmags. I think that pretty much settles it with that evidence, don't know why I didn't make that connection till now.

Also anyone have a suggestion on a general purpose degreaser to use without having to grab a fancy gun degreaser from a gun store? Something like simple green perhaps?

 

[breakingcontact]

Id blame it on your range partner! I didnt think of popping the buffer tube out. I usually keep them dry or with just a wipe down of the spring with a lightly oiled cloth. If the lube back there attracted enough junk it may not be compressing all the way or too slowly?

 

[40Arpent]

Also anyone have a suggestion on a general purpose degreaser to use without having to grab a fancy gun degreaser from a gun store? Something like simple green perhaps?

Non-chlorinated brake cleaner. Just keep it away from the plastic.

If you do use Simple Green, make sure you rinse well with water. Simple Green likes to eat aluminum.

 

[rushthezeppelin]

Id blame it on your range partner! I didnt think of popping the buffer tube out. I usually keep them dry or with just a wipe down of the spring with a lightly oiled cloth. If the lube back there attracted enough junk it may not be compressing all the way or too slowly?

The lube itself was pretty darn clean just that damned tendency of froglube to congeal when cold is what got me I think. Soon as it got to that 40* ambient temp it started negatively impacting the speed of the buffer. Will report back once I clean it and get to the range again so all you other people who use frog lube know to watch this.

Non-chlorinated brake cleaner. Just keep it away from the plastic.

If you do use Simple Green, make sure you rinse well with water. Simple Green likes to eat aluminum.

Awesome, thanks. Pretty sure I have some brake cleaner in the garage. I'll make sure to take my stock off and be careful not to get any on my ergo grip. As to mopping it up should I just stuff the tube with a paper tower or something

 

[40Arpent]

As to mopping it up should I just stuff the tube with a paper tower or something

I use a rag, but paper towel will work.

 

[rushthezeppelin]

Well just got back from Red's (I know I know, but I HAD to test a batch of 223 reloads in a controlled environment). Was still having the occasional cycling problems (bout every 10 shots or so) so at that point I was convinced it was my gas block. Asked the RO if he had an allen set I could possibly use since I forgot mine. He directed me to one of the newer guys inside who was ever so kind as to set me up on their upper vice block and helped me out. Take the HG off and sure enough my gas tube was canted about 2 or 3 degrees off, pretty obviously the problem at that point. Helped me get it back and even locktited it for me (although it was blue locktite so its probably already burned off but we did torque it down extra hard this time). Probably the best experience I've had from the employees at Red's so far, they earned a bit of continued business from me. No customer idiocy today either.

So in conclusion I think the day at BOTW was a combo of gas block alignment and the sticky buffer tube. My AR now runs beautifully like it should.

On a side note my loads I worked up were way too light. They were obviously not cycling enough and my first one of the lightest load even stovepiped on me. Back to the drawing board I suppose.

 

[Sugar Land]

Frog lube gums up bad. Did you heat up the material before applying?

 

[breakingcontact]

Glad you got it figured out.

 

[rushthezeppelin]

Glad you got it figured out.

As am I, I get to feel comfortable using my AR for home defense again which makes me feel much better over using my 9mm (not knocking my 9 but the ability to put shots on target more quickly is a comforting thought).

Also figured out a nifty way to clean crud off the muzzle of your AR and make blinding fireballs in the process. I lost my crush washer for my flash hider when we were out at BOTW and ended up taking my comp off at Red's. Muzzle crown is nice and squeaky clean now. Turns out no muzzle device is almost as bad as a comp though in terms of noise and concussion so I'm just going to use my comp tomorrow. Will make the recoil much more manageable anyway, amazing how much even an A2 FH reduces recoil compared to nothing on the end of your gun.

 

[rushthezeppelin]

Spoke too soon yesterday. Had a few more feed problems at the range again today. Luckily Red's "AR expert" was there and first thing he did was extended the bolt in the carrier then set it down bolt head first on the counter. Dropped right down with no force and he told me my gas rings are on the way out. Did some research and it looks like he's on to something. Bolt should hold the weight of the carrier with gas rings at proper spec. Some people say that you should only replace if the bolt will drop down from the carrier when held upside down, but I think that's only in extreme cases where you have cycling issues every time, which mine are only about every 10 to 20 shots. Regardless I can definitely feel a bit of play when inserting the bolt into the carrier so it's pretty obvious I'm not getting a 100% seal from my gas rings.

Anyone know of any places local in Austin who might carry gas rings, preferably on N side or up in Williamson?

 

[gdouthit]

Spoke too soon yesterday. Had a few more feed problems at the range again today. Luckily Red's "AR expert" was there and first thing he did was extended the bolt in the carrier then set it down bolt head first on the counter. Dropped right down with no force and he told me my gas rings are on the way out. Did some research and it looks like he's on to something. Bolt should hold the weight of the carrier with gas rings at proper spec. Some people say that you should only replace if the bolt will drop down from the carrier when held upside down, but I think that's only in extreme cases where you have cycling issues every time, which mine are only about every 10 to 20 shots. Regardless I can definitely feel a bit of play when inserting the bolt into the carrier so it's pretty obvious I'm not getting a 100% seal from my gas rings.

Anyone know of any places local in Austin who might carry gas rings, preferably on N side or up in Williamson?

How many rounds have those rings gone through.

Mine wouldn't hold the carrier one day and I broke the BCG down cleaned it up and put fresh oil on it. it passed the "test" after that.

 

[breakingcontact]

Spoke too soon yesterday. Had a few more feed problems at the range again today. Luckily Red's "AR expert" was there and first thing he did was extended the bolt in the carrier then set it down bolt head first on the counter. Dropped right down with no force and he told me my gas rings are on the way out. Did some research and it looks like he's on to something. Bolt should hold the weight of the carrier with gas rings at proper spec. Some people say that you should only replace if the bolt will drop down from the carrier when held upside down, but I think that's only in extreme cases where you have cycling issues every time, which mine are only about every 10 to 20 shots. Regardless I can definitely feel a bit of play when inserting the bolt into the carrier so it's pretty obvious I'm not getting a 100% seal from my gas rings.

Anyone know of any places local in Austin who might carry gas rings, preferably on N side or up in Williamson?

Call AGL in RR. They usually have some AR parts in the back.

 

[rushthezeppelin]

How many rounds have those rings gone through.

Mine wouldn't hold the carrier one day and I broke the BCG down cleaned it up and put fresh oil on it. it passed the "test" after that.

Sitting at I think around 1600 rounds. And I cleaned the living crap out of my bolt after the range trip with some degreaser a bit ago. Still failed the test. Granted alot of people report failing the test without having any issues whatsoever (most seem to fail the test after only 600 or so rounds) but I figure for 2 bucks a set they are incredibly cheap insurance to make sure everything runs smooth at least from the perspective of having a flawless gas seal. Preventative maintenance is key to helping reduce the likelihood of a failure when you need your rifle the most. Like I said mine were definitely quite loose in the carrier so no doubt they were letting gas through. Couple that with running mostly lower powered 223 and seems like a very likely culprit to me. Will report back with how this fix works out for me.

 

[gdouthit]

I got that many or more through mine. I need to get a few sets of rings to have on hand.

 

[rushthezeppelin]

I'm sure the biggest contributing factor to the somewhat early wear (I've heard of worn rings giving people short stroking problems as early as 1k) is all those dusty windy days at BOTW

Looks like Guns+ is the only thing up here open tomorrow so I will have to check give them a call and see if they have any. If not I'll check out AGL tuesday (if they aren't closed for xmas eve).