AR 15 Jams

[Guest PistolFan]

Went to fire new AR 15 using 5.56 ammo but could not fire over 2 rounds without a jam. Anyone else had this problem? Haven't tried 223's yet.

[Mike]

Description of the jam? Pictures? What kind of magazines are you using? Ammo? Rifle info?

Mike

[frankmako]

Description of the jam? Pictures? What kind of magazines are you using? Ammo? Rifle info?

Mike

plus one, need more info.

[Guest PistolFan]

20 round c products magazine, PSA standard moe 16 inch, spike tactical lower, american eagle 5.56 ammo no pics. Bolt closes with new round but doesnt lock. Also tried different magazine with same results. However my xd 45 and 9mm beretta performed flawlessly. Thanks for any info.

[TGO David]

20 round c products magazine, PSA standard moe 16 inch, spike tactical lower, american eagle 5.56 ammo no pics. Bolt closes with new round but doesnt lock.

It sounds like the AR is short cycling which can be the sign of too small of a gas hole or an obstruction in the gas tube. This would cause it to fail to lock back and would cause it to jam while trying to eject the spent casing and strip off the next round. What make / model / length upper receiver group are you running on your lower?

[Raoul]

tell us more about your AR. What's the upper?

[Guest PistolFan]

It is an m4 moe flat top with 16 inch barrel. I hav only fired about 5 rounds through it. The other magazine was a 30 round magpul 5.56 x 45. The weapon is from Palmetto Armory. A friend of mine has the same with no problems. MOE upper, BCG charging handle. Barrel 16 inch, MPI 4140 Steel ,M4 Profile, 5.56Natochamberwith 6 groove, 1:7 right lead tapped and air guage bore., carbine length gas port andm4 feedramps. Barrels pinned,f-marked, front sighht post and a2 flash hider . Upper forged 7075-T6 A3 Ar upper ismadeto MIL-SPECS and finish. Bolt is mil spec carpenter 158 steel . Shot peened. MPI and HPT. Bolt carrier is parkerized outside

Here is the whole page of info

Palmetto State Armory 16" M4 Standard MOE Rifle Kit

[Dolomite_supafly]

If the bolt will not lock closed it is either ammo out of spec, dirty chamber, or the chamber dimensions are wrong. If this is the first time you have fired the gun I suspect it would be the last. If you still can't close the bolt with the forward assist then it is a chamber headspace issue. Try cleaning the chamber really well with a brass brush and if it still continues then contact the maker.

Dolomite

[Dolomite_supafly]

I believe he is having a closing issue and not a locking open issue.

Dolomite

[TGO David]

I believe he is having a closing issue and not a locking open issue.

Dolomite

I read it the other way but you may be right. Headspace issues would definitely cause it to fail to lock into battery. I'd stop shooting that thing until he knows for sure; bad head spacing can be very bad juju.

[RWF]

make sure there is no trash, or debrie in the lugs area of the barrel extention. or between the carrier and reciever to slow it down.

because if i understand it right it fires, ejects picks up the new round but does not fully lock up.

i really do not think this would be it, but remove the buffer and spring, make sure there is nothing there and it is clean. if you still have problems borrow a BCM and see if it will run. i have had a new bolt before that was worthless.

[Mike]

Find someone with a 5.56 chamber reamer. Dump the low quality C-Products magazines.

Mike

[Caster]

Dump the low quality C-Products magazines.

Mike

That was my first thought. Bum a Pmag from someone when you're ready to try it again.

[Guest PistolFan]

Has anyone shot the american eagle brand?

[Caster]

Has anyone shot the american eagle brand?

Tons of it. Never one single issue.

[Dolomite_supafly]

I have ran thousands of trouble free rounds from C-Products mags. I would not consider that the issue if the gun will pick up a round and chamber ite bolt will not lock up.

Drop the P-Magswhen the weather turns a bit colder. They will be damaged more than a all metal mag. I have seen feed lips break on several P-Mags during cold weather. Maybe no Tennessee cold but cold enough to cause problems when metal mags survived without issue.

For the anti C-Prodcuts people have you actualy had an issue or is it something a friend told you about? I used C-Products mags to fix issues other mags have caused.

Dolomite

[Mike]

I have ran thousands of trouble free rounds from C-Products mags. I would not consider that the issue if the gun will pick up a round and chamber ite bolt will not lock up.

Drop the P-Magswhen the weather turns a bit colder. They will be damaged more than a all metal mag. I have seen feed lips break on several P-Mags during cold weather. Maybe no Tennessee cold but cold enough to cause problems when metal mags survived without issue.

For the anti C-Prodcuts people have you actualy had an issue or is it something a friend told you about? I used C-Products mags to fix issues other mags have caused.

Dolomite

C products have been some of the poorest quality mags I have ever run in my rifle. They consistently had spread feed lips, on a new magazine, and caused many issues. Their quality control was non existent. They went out of business for a reason.

Mike

[Guest PistolFan]

The same thing happened using magpul magazine. Suppose to be military issue.

[Raoul]

I've used suplus mags in my AR since I built it. Never had an issue.

[Mike]

The same thing happened using magpul magazine. Suppose to be military issue.

Sounds like a tight chamber. Find someone with a reamer.

Mike

[BrasilNuts]

I'm gonna go with a Karl Childers reply here... Did you clean and oil it before your first range visit?

[Dolomite_supafly]

Sounds like a tight chamber. Find someone with a reamer.

Mike

Unless the chamber is chrome lined. Can't ream a chrome lined chamber. Well I guess you could but it will cause all kinds of issues.

Dolomite

[Mike]

Can't ream a chrome lined chamber. Well I guess you could but it will cause all kinds of issues.

I don't know where you're getting that. I know plenty of people that have used Ned's throat and shoulder reamer on chrome lined barrels to no ill effect. The chrome lining around the throat naturally erodes over time anyways.

Michiguns Ltd. - AR-15 Tools and Accessories

Mike

Edited September 12, 2011 by Mike

[Dolomite_supafly]

I don't know where you're getting that. I know plenty of people that have used Ned's throat and shoulder reamer on chrome lined barrels to no ill effect. The chrome lining around the throat naturally erodes over time anyways.

Michiguns Ltd. - AR-15 Tools and Accessories

Mike

I'll admit that my experience in reaming chrome lined chambers is from second hand experience from shops and smiths I have spoke with over the years.

I went and did a search and it seems as though it isn't as big of an issue as I was lead to believe. It does take a special reamer as the chrome is very hard but it is possible and doesn;t have the side effects I was made to believe.

I have never owned a chrome lined gun ever so I have never really looked into the issue, I only relied on other's words. I have always used stainless barrels so there was no need for me to have chrome, at least not for corrosion resistance. Chrome lined bores were used to extend the life of the barrel as well as for corrosion resistance. There are several types of coatings and treatments that seem to work better. The reason why chrome is used mostly is probably due to cost over the other methods.

Thanks for enlightening me, I appreciate it. I try to learn something new every day and you have made my quota for today.

Dolomite

[piercedan]

This doesn't sound like your issue, but I thought I'd throw it in anyway just in case. I have a buddy with an AR that has the front A-site removed and a low profile gas block in place. He kept getting jams and short cycles because the block would creep a little and reduce the gas flow. Once he got it adjusted correctly and lock-tighted down, the problem was resolved.