Stuck bolt in AR15

[randyman]

I recently completed building my first AR using an Anderson lower that I assembled with a Geissele 2 stage trigger. I bought a complete Anderson upper with an 18" barrel and hooked that up to my upper with a featureless stock to avoid having to register it here in Ca. as an evil assault rifle.
I took it out to test fire and loaded a magazine with some factory reloads I bought on-line. I pulled the trigger and only heard the click of the trigger falling. I tried to pull the charging handle back to eject the round but it was jammed tight. It took 2 of us to pull the handle back-one holding the gun in a safe direction while I pulled as hard as I could. It finally released and the unfired round ejected with no indication that the firing pin had touched it. Figuring it was a faulty round or operator error I put the mag back in and chambered another round making sure the charging handle was completely closed. I pulled the trigger again and only got the sound of the trigger falling again. This time it was a little harder to get the charging handle to pull the bolt back and eject the unfired round that also didn't have any indication the firing pin had hit it. Being a slow learner, I tried it all again with the same results only this time it took using a block of wood and a hammer to get the charging handle and bolt to release. This time, now that the gun was unloaded it went back into the case.
I took the gun into the shop where I had purchased the upper and we removed the upper and bolt carrier to see what was going on. We didn't see anything obvious but I left the gun with him so he could test it out the next day. He loaded his magazine with factory new round and said it fired 3 rounds with no problems and gave it back to me.
I wasn't going to have a chance to shoot if for a few days and was describing my problem to a friend. I had a fired case that I painted the spent primer with a black sharpie from another gun and put it in the chamber to see if the firing pin was going to hit the primer. I pulled the trigger and again the charging handle and bolt were jammed so hard we couldn't get it out.
I took it back to the dealer and had the builder of the upper inspect it. His claim is the factory reloads and the fired case from another gun were the culprit. I'm pretty skeptacle but am also new to these AR's so I'm hoping some of you more experience shooters and decipher my description of the problem and help me out. Any ideas? Thanks, Randy.

[dsandfort]

Could indicate the need for a small base die to get that little extra sizing down low on the case.

[savageboy23]

What brand are the factory reloads? I have shot the ultramax brand out of both my ars fine. Not an issue anymore being I load my own and have the small body base die. I had a similar experience when I had my first ar built. But in my instance I needed a little lubricant on the bolt carrier.

[MZ5]

Just some thoughts here. I don't follow ARs any more. I had some in the increasingly-distant past, but don't know what parts brands are what these days. So, in that context:

The thing you were told about the issue being the cartridges is quite possible. Try some new-manufactured (not re-man) ammo. What you're describing could well be cases that are just slightly too large for your rifle's chamber getting stuck before the bolt is fully in battery. That out-of-battery condition would prevent the rifle firing (no dents in the primers), but it can look like everything is okay upon quick/casual glance if one is not familiar with exactly what the bolt carrier & bolt head looks like through the ejection port when it's fully in battery.

The fact that a piece of once-fired brass from some other rifle doesn't fit is to be expected. One doesn't expect any piece of brass fired in one rifle, to fit in the chamber of another until/unless it is full-length sized. It would surprise me slightly if commercially re-manufactured cartridges don't fit in a SAAMI-spec chamber, but it could be. Alternatively, your chamber could be very small. Is the barrel you bought sold or intended as a 'tight' or 'match' chamber/barrel? If so, and if it's right at the small end of spec (or smaller), then it's less surprising that re-man ammo might not fit correctly.

[Bill K]

My thought on this is #1, the reloads are expanded too far at the base and jamming tight into the chamber, but also not fully seating, so no go on fire and super tight opening the bolt to remove the round. Get a set of small base dies for your reloading. #2, are you using 5.56 ammo/cases in a chamber that is only chambered to 223 rem. if so the 5.56 ammo/neck is just long enough to jam in the chamber/neck area and causing it to fit too tight. Just a couple things to check and/or eliminate in solving your issue. Bill K

[MZ5]

I'm not seeing anywhere that OP is reloading his brass. Did I miss it? I'm seeing that he bought factory re-man ammo (factory loaded ammo made with used/reloaded brass). Thus, he does NOT need small-base dies.

On that topic, though, I've honestly never seen a semi-auto that _needed_ small base dies. I've seen brass that needed to be replaced, and one could have a sufficiently tight (in some dimension) chamber to require them, it's just that I've never happened to have come across one, of any design.

[randyman]

Thanks for the replies. You're right MZ5, I was using re-man ammo so I could accumulate some brass to reload my own. I now realize in hindsight it was not very smart to try putting a fired brass from someone else's gun to troubleshoot. I was pretty sure my problem was a bolt/trigger/firing pin problem and thought that would tell me what I needed to know. I did get a chance to put a micrometer on 3 different types of ammo and measured right at the base below the extractor groove. Independence AR 5.56 measured at .374. Tulammo .223 came in at .375 fat and the factory reloads that shall remain un-named was also .374. Maybe a digital micrometer would show a different spread but I'm an old fashion dial reader and that's what I came up with. I'm suppose to get my rifle back on Monday and I'll try loading some factory and see what happens.
Bill K-what you're saying might make sense-I didn't ask if the upper was for .223 specifically or for 5.56. I see your profile lists your location as Lake Forest. Is that the Lake Forest I drive thru on my way to Eagle Lake? Thanks again guys-Randy.

[Bill K]

That is the place.. Hope you can find the issue, so you can feed and fire that weapon... I am easy to locate, if you pass by here. Bill K

[randyman]

I did some research on small base dies and see what I'm pretty sure is my problem. If the bolt doesn't fully close, the firing pin isn't able to hit the primer. That's what had been happening and with the case stuck due to being slightly to large, I'm not able to extract with the charging handle. I'm ordering an L.E. Wilson headspace gage tomorrow and can check all my ammo before putting it in the gun.
Bill-I drive thru there several time each summer after they open the road for through traffic. We have a place at the north end of Eagle Lake that we go to even though there hasn't been any water at that end for a few years. I still use it for home base when the squirrels are out as it's only about 35 miles from where we hunt. I bought my .204 just for that and now I have the AR to see how it does. My next AR will probably be a .204 as well. Randy.

[MZ5]

What ammo was used that was said to have fired properly? You could measure some of that.

I did get a chance to put a micrometer on 3 different types of ammo and measured right at the base below the extractor groove. Independence AR 5.56 measured at .374. Tulammo .223 came in at .375 fat and the factory reloads that shall remain un-named was also .374.

If any of that ammo will chamber and fire, then the problem is not that dimension (and, again, you would NOT need a small-base die if you ever decided to handload). SAAMI's minimum size for the chamber at that point (approximately, since you'd need to compare where you measured vs. where SAAMI says to measure) is 0.3769" +0.002"/-0" SAAMI-max spec for the cartridge case there is 0.3759" +0"/-0.008". In other words, if that dimension is the issue, then your chamber is out-of-spec, but the ammo is not.

Some things to consider:
1) Might the bullet ogive be hitting the lands? In recent years, a surprising number of ARs in a variety of chamberings have had short throats (or right at minimum), causing factory ammo to either not chamber, or create excessive pressure. NOTE: Some factory ammo is built a bit too long for a 223 chamber. That's one reason you'll see some Hornady ammo marked as 5.56x45mm and some as 223 Rem. The 5.56 is longer in terms of where the ogive ends, so it won't chamber in a SAAMI-minimum chamber.

2) There are lots of other dimensions to check. Base-to-datum-ring is one, dIameter at the body-shoulder junction is another, base-to-shoulder is another, overall brass length to the mouth, and base-to-ovgive are some.

My GUESS is that this is a matter of the bullets jamming the lands and preventing full chambering. Look very closely and carefully at the bullet, right at the transition from the shank to the ogive. If you see scuffs at regular intervals around the bullet, that's the issue.

If you don't know where to get all the dimensions I'm talking about, above, go to SAAMI's website and download the full centerfire rifle specs. It's actually an ANSI Standard; Z299-4. See here: http://www.saami.org/specifications_and ... /index.cfm

Let us know what you find out!

[Jim White]

I'm ordering an L.E. Wilson headspace gage tomorrow and can check all my ammo before putting it in the gun.

Good choice. Incidentally, when those rounds were extracted were there any marks on the brass and/or the bullets? When you get your case gage set your sizing die up per the instructions of the case gage.

Make up a a couple of dummy rounds with the max OAL and see if they'll cycle through.

HTH,

[MZ5]

What ammo chambered and fired?

[Bill K]

I did some research on small base dies and see what I'm pretty sure is my problem. If the bolt doesn't fully close, the firing pin isn't able to hit the primer. That's what had been happening and with the case stuck due to being slightly to large, I'm not able to extract with the charging handle. I'm ordering an L.E. Wilson headspace gage tomorrow and can check all my ammo before putting it in the gun.
Bill-I drive thru there several time each summer after they open the road for through traffic. We have a place at the north end of Eagle Lake that we go to even though there hasn't been any water at that end for a few years. I still use it for home base when the squirrels are out as it's only about 35 miles from where we hunt. I bought my .204 just for that and now I have the AR to see how it does. My next AR will probably be a .204 as well. Randy.

Randy, good area out from your area/place at the lake. You must be going up around Adin/Bieber, from there. We shoot around the Grass hopper flats and such for the critters. Are you at Spaulding's or Stone's ? I think you will solve your issues with the small base dies. They are used and should be on most auto loaders, for good reliable feeding. Bill K

[randyman]

We're at Stones. I usually turn off at grasshopper flats and head East towards the highway. Sometimes end up at Alturas ranch but they poisoned with cabbage last year and did a good job of getting rid of the squirrels.

[Bill K]

Got you. I shoot the flats out that way, not a lot of ground squirrels, but some and usually not too many traveling in and around there. I stay on the dirt portion, but sometime to go to the highway/paved and then cut back towards Horse lake (road) and back out to 139 across from the 5 dot. Bill K