AR-15 won't cycle after using cast bullets

[hornady308]

I have a standard milspec grade AR-15 with a 300 Blackout barrel. The rifle was working great with copper jacketed bullets, but I tried some cast bullets and now the action will not cycle at all. I went back to firing copper jacketed bullets but the action still would not cycle. I could use a little help with where to look for the trouble and what to do about it. Thanks for the help.

[ShooterAZ]

My first thought would be a plugged gas tube/port. More info would be helpful, such as the load you are using.

[gnostic]

Try a process of elimination with the gas system. I'd start with the bolt, gas key etc. Try squirting solvent thru each component until you find the obstruction.

[country gent]

Im thinking lube or other contaminant in the gas tube restricting flow of gas. I would pick up a new one and try it, ( gas tubes are a real pain to clean of hard deposits). or clean the old one. I used to se long pipe cleaners for this. Soaking in solvent or an ultra sonic cleaner will work also

[cwlongshot]

I agree start with gas system...

OOH forget about cleaning the gas tube... Just buy a new one be sure you get a couple roll pins too. The tube is CHEAP compaired to the PIA job of cleaning one...

Hopefully your gas block can be cleaned. its doubtful lead got to the gas key, but stranger things have happened.

Good luck

CW

[lefty o]

if it worked before you shot lead thru it, but now doesnt, id be looking at the gas tube/gas block.

[oldracer]

AR's and those are not made to shoot un-jacketed bullets. Due to the high heat generated I agree that there is lead build up. I also see folks at our range trying to shoot steel cases and they don't work well either.
John

[Tripplebeards]

My first thought would be a plugged gas tube/port. More info would be helpful, such as the load you are using.

Yep

This us why I don't run cast through my ruger carbine

I'm guessing if your boolits were powder coated you'd have a better chance of it not plugging.

[popper]

Just put a small hose on the gas tube and blow through it (or compressor if you have one) I've had the gas key full of junk and it still would cycle, hole in the junk was same dia as barrel port. Soft alloy with subs or supers may plug the barrel port. Bolt rings may get stuck with accumulation but then hand cycling is difficult. PC is OK even for PB supers. Hard lube can accumulate in the GB but solvent will remove it.

[marek313]

The only time i had any lead in my 300AAC with PCed cast bullets was around gas tube connecting to the gas key and it was sticking when manually cycling the bolt. I'm guessing you have some leading inside the gas system somewhere that prevents gas from cycling bcg. i didnt have any blockages like you but I would start looking there as everyone suggested.

[too many things]

dont use cast will fix problem

[Moleman-]

I've got a few uppers that I use with lee tumble lube bullets with alox and then dusted with mica which can really clog things up with lube. The bolt carrier group especially gets dirty when you put a few hundred cast loads through it. While you're shooting it and it is warm the excess lube seems to be blown out of the vent holes in the carrier, but after it cools if you don't clean it when it's real dirty it can cause sluggish operation the next time up until it gets warmed up. Never have replaced a gas tube yet as full power jacketed loads seem to clean it out.

[Hamish]

A couple of the comments in this thread make me want to slap their Momma's.

I'll keep running cast in my AR's, thank you,,,,,. We know that if you fire unsuitable loads, no matter the action type, crud/leading can occur.

[hornady308]

Problem solved...it was a plugged gas key. I have fired cast bullets in lots of semi-auto pistols, including a .44 Desert Eagle, and never had a problem. Same for semi-auto rifles such as an L1A1, SKS and AK. Never a problem. I personally have no interest in owning any firearm that cannot be uses reliably with cast bullets. Thanks for all the help.

[oldracer]

I agree with not owning any firearms that can't shoot cast bullets...…..all I own are muzzle loaders!

[hornady308]

BTW, the blockage in the gas key turned out to be a blown primer. The problem had nothing to do with cast bullets and everything to do with a crappy job of reloading.

[Smoke4320]

Glad you got it worked out .. Sometimes gas issues can be difficult to figure out

[Boolit_Head]

That is odd, I've got a blackout that I exclusively shoot cast with and without a suppressor with and it has yet to hiccup.

[popper]

BTW, the blockage in the gas key turned out to be a blown primer. How did that occur? Just curious as it seems like a 1M:1 chance.

[Boolit_Head]

Blown primer makes more sense than cast plugging it. But dang the chances that it would end up there!

[Driver man]

I would think that the primer was in the case when it was reloaded. These things happen

[dkf]

A couple of the comments in this thread make me want to slap their Momma's.

I'll keep running cast in my AR's, thank you,,,,,. We know that if you fire unsuitable loads, no matter the action type, crud/leading can occur.

Same here. Don't tell my ARs they shouldn't shoot cast.

If you are getting enough lead and lube to stop the gun you have some major problems with your boolits and reloading practices. Probably need a better lube too.

I only ever blew 2 primers out in an AR and that was working up 5.56 pressure jacketed loads.(wasn't even at max yet) The primers were not crimped in and for those particular loads they should have been. That is why milspec is for crimped primers on 5.56.

[Tripplebeards]

You guys are going to make me try cast in my ruger carbine

[Finster101]

You guys are going to make me try cast in my ruger carbine

There is no reason no to. I have a 995 and it eats everything I throw at it. I have two .300 Blackout uppers that get nothing but PC'd cast. Haven't had any issues out of either of them yet.

[GhostHawk]

I'm with Finster.

All of my hipoint carbines eat cast lead. I've had 2 9mms, .40sw and the .45acp. All rock just fine with cast.

I have had lead show up in the gas system of my SKS, but never enough that it would not function.

Being a Yugo SKS it is dead easy to turn the gas off and shoot them single fire, like a straight pull bolt.
Which I have been known to do. It is also the cheap way, as 4.6 grains of Red Dot below the .314 90 gr TC cast boolit makes a great little SKS plinker round. It just won't cycle the action.

But better lube and better sized boolits drastically reduced how much lead I saw in the gas system afterwords.

Was never enough to get me to not shoot lead in it.

If I can't shoot cast in it, it won't last long at my house.

[hornady308]

the reason I had a blown primer was due to an overpressure situation from the use of converted brass that had not had the necks turned. My chamber is tight and I know that I have to turn every piece of brass if it is from converted 5.56mm. The blown primer came from a case with an FC headstamp. These are well known to have thicker necks when converted to 300 Blackout. I could have avoided the entire situation by using new brass made to 300 Blackout specs, but I am a cheapskate.

[popper]

If you mean the primer ended up in the channel for the bolt pin, I can see that - inside the gas key? Naw. Anyway, I neck turn all my brass, converted or not. Uniforms neck thickness - you wouldn't believe how bad some factory stuff varies. Hand held RCBS rig but put the case in elec drill. Goes pretty fast.