AR jams round in chamber

Does the ammo work fine on other rifles?

Try a new action spring

Try SB dies. you lose a few reloadings per case, but you gain sure functioning.

If your other AR's run fine with the same ammo, ditch that barrel. Get one with a proper NATO spec chamber, a tight match chamber on a 7.5" barrel to be run suppressed is not very smart anyway. Why do you want a tight match chamber on a short barrel that will not be used for match shooting? Why would you also want this tight chamber on a short barrel that will have a suppressor forcing more fouling back into the action and chamber?

Sounds like the whoever sold the barrel was more worried about marketing than they were about actual function.

I acquired my ar 3 days before Sandy Hook. I tried several methods of reloading. The gun suffered the same problems yours does, if not worse, being a production Sig 716. And I simply could not get my hands on factory ammo. I had friends tinkering with it and I even tried different lubes and some local gun smiths. I kept I assuming my loads were off.

After being too busy to think about it for 2 years I ended up trying factory ammo. The gun jammed way worse and had the only dangerous bullet set back I had seen. I called sig and sent it in. Five days later I got it back with an email saying my chamber was too tight. I have shot atleast a thousand reloads in it with out one single hiccup. Ive crimped, not crimped, Ive had no problems. I think you should clean it up and run premium factory ammo. If it jams at all I would find somebody to polish the chamber.

I feel your frustration, it annoyed the heck out of me. However, it taught me alot about loading, and I found ultimate relief when I cycled through my first hundred reloads.

Polishing the chamber won't do much, if it's tight it needs to be opened up with an appropriate reamer. If the factory will do it for free then great, but having a gunsmith do it will probably cost more than the barrel is worth. If it is a chrome lined barrel and chamber, opening up the chamber will trash the chrome lining and you're going to need a new barrel.

If it is a chrome lined barrel and chamber, opening up the chamber will trash the chrome lining and you're going to need a new barrel.

Click to expand...

Unless one were to use a carbide reamer, it'd trash the reamer, too, leave you with a chamber that looks like it had been finished with a chinese twist drill. Chromium doesn't just have excellent corrosion resistance; it's also very hard, with hard chrome plating coming in at over 65 Rockwell C, which is harder than HSS tooling.

I crimp my AR ammo. I use a taper crimp die which is much more forgiving as far as case length variation. Mine is CH4D.

After loading, I drop every round into a case guage from JPRifles.com. Go to the address below and click on case gauges.

http://www.jprifles.com/1.5.1.2_maint.php


These are the same size/shape as your chamber. If it will fit the gauge, it'll fit your gun. Slamfire had another brand/version of this in his post.

MachIVshooter said:

Unless one were to use a carbide reamer, it'd trash the reamer, too, leave you with a chamber that looks like it had been finished with a chinese twist drill. Chromium doesn't just have excellent corrosion resistance; it's also very hard, with hard chrome plating coming in at over 65 Rockwell C, which is harder than HSS tooling.

Click to expand...

Also amply true. All signs point to this being a chamber issue, and with an AR barrel the easiest way to solve it is to buy a new barrel with a properly dimensioned 5.56mm NATO chamber.

I know everyone loves fractional accuracy improvements offered by tighter match type chambers, but I am of the firm opinion that such chambers have little to offer in practical accuracy improvement versus the very real downsides to the reliable function of an auto loading firearm, particularly under adverse conditions.

Remember the military also loves accurate rifles and carbines too, but they have learned from experience that sacrificing reliability for tiny accuracy enhancements is not a good trade off.

I agree somewhat with the above post, new barrel is easy and inexpensive. Pretty easy for general population get them for about $100-115, and smiths and FFLs to get them for $80-100.

Regarding the chamber, I am impressed with the .223 Wylde chamber. All my latest assemblies have used that and I have had zero complaints. It's designed for both 5.56 and .223. Seeing a lot of them in the various marketplaces these days.

http://www.americanweaponscomponent...the-caliber-confusion-223-wylde-vs-5-56-nato/




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I've seen this complaint more times than I can count and have even had some
rounds that did the same.

The solution is simple. Either don't crimp or if necessary use a Lee Factory Crimp die and crimp as a separate operation. If using a Dillon 5-station progressive like the 650 just put the crimp die in the last station.

Crimping with a seating die REQUIRES that EVERY case be of the same length or some will be crimped too much and the extra pressure will bulge the shoulder/case wall junction. Cartridge will still fit in Wilson type case gauges but not the chamber of the rifle (.223, .223 Wylde, or for that matter even 5.56mm)

Has nothing to do with case sizing or type of FL sizing die. Just excessive crimping that's distorted the case.

Read the OP's statements. He has 2 other AR's that run just fine on the same batches of reloaded ammo.

He has a chamber issue. Everything else is well meaning advice, but won't solve his issue. Tight chambers are great on national match rifles with rifle length gas systems and frequent cleaning, but have no place on a shorty pistol length gas system with a can screwed on the end of it.