I built my own 6.8 AR-it has a 16' ARP barrel, a stag bolt, and the ALG EMR rail with their proprietary barrel nut. I followed the shim and torquing instructions included.

The first time firing it, the spent case stuck in the chamber with bolt most of the way home and I could not open the bolt with the charging handle. When I got it home I pulled on the charging handle while dropping the stock against the ground and it freed the stuck case. The case was not deformed in any way.

Wondering what could be wrong-misaligned gas tube, headspace issue, or bolt needing to be better lubed or worn in. I sprayed the bolt down with CLP and wiped it with some Mobil-1 prior to shooting it but I did not completely take the BCG down and clean/lube it when apart.

Any thoughts before I take this to a gunsmith? Its a bummer, I put a scope from another rifle on it and the first shot was dead level with the bull and about 4" right at 100 yards. I had high hopes for this one.

Thanks,

A case getting stuck in the chamber wouldn't be a bolt or gas tube issue. I'd look at the ammo first, and then the chamber. It's also possible for the upper receiver and/or barrel nut to not be square, which puts torque on the chambered round. I'd definitely try different ammo first though.

Let me get CharlieSierraDelta to chime in. He'll know what to look for.

Is there any scrapes or scratches on the case? Have you tried any more cartridges, just chamber and eject to test function?

I can think of 3 things It could be.

1- out of spec ammo. Maybe try a different brand.

2-out of round or rough chamber.

3- incorrect bolt. Spc1 with spc2 chamber.

I would bet on #3

I wouldn't bet on that at all. I don't think anyone has sold an SPC1 bolt, barrel, or ammunition meant specifically for SPC1 chambers in years. If I'm not mistaken, the chambers are still the same dimensionally, and only vary in freebore and twist rate. Additionally, the bolt is the same between the two, and most ammo can be safely interchanged between the two.

Most issues like this are ammo related. I've had ammo get stuck in a dirty chamber, a chamber I didn't clean before shooting, and I've had reloads that weren't sized properly get stuck. So this begs the question- what ammo were you shooting?

Shooting Federal 90 grain soft point-the white box. The gun is all brand new parts and I cleaned it well before shooting.

Could just be a rough chamber.
I've had this happen a few times. I ended up polishing the chamber. Haven't had any issues since.

That's pretty good ammo, so that seems to point the finger at the barrel now. Do the rounds cycle fine by hand, or do they only jam after firing?

Educational thread about these female rifles.

Y'all keep going, I'm absorbing good information.

The difference between spec 1 and spec 2 is there is more freebore in the spec 2 chamber. There is not a 6.8 spec 1 and different spec 2 bolt, only 1 bolt. Ammo is loaded to the SAMMI which is a spec 1 chamber except when Silver State Armory was in business they loaded a "TAC" load only for spec 2.

Does the carrier lock back on the bolt catch on an empty mag? Any abnormal wear marks from carrier riding in receiver or scratches on the brass? I only use ARP barrels and my guess is the melonite in the chamber is causing the round to stick. I run a hone in before assembly to get rid of the melonite. This could be the only reason but could also be compounded with a gas issue.

Give me a call and I can walk through some things for you to check.

First of all, as hdfireman mentioned, there is no such thing as a spec 1 or spec 2 bolt. I'm not sure why people post incorrect information like that. If you don't know, just don't post.

I would clean everything thoroughly, paying special attention to make sure you get all the oil/grit out of the chamber, and then lube everything very well and hand cycle about 100 times. After cycling clean and lube again before you shoot. This may very well solve your problem. I would do this before jumping to gas system, headspace, or bolt issues.

IF it's an ARP barrel made in last 2-3 years, it's probably GTG, both in chamber and gas hole size.
The rest of the parts seem to be good quality also.
Resist the temptation to ease the bolt/round into the chamber - use the bolt release.
Don't pull the charge handle back and simply release it - it may create drag and not let the round chamber completely.

Start simple, put 1 round in the mag and pull bolt back with charge handle and LOCK the bolt back.
Close the charge handle and drop the bolt with the bolt release, go ahead, let it drop, it's designed to do that.
Next, fire the rifle.
Did the bolt lock back after that round?
Did it lock back all the way (like you pulled it back with CH and locked it) or just on ridge of bolt?
If it locked back all the way, you are probably OK on gas.

Since it locked back on one round, put 3 in the mag and try it again.
If it cycles and locks back on last round, it's probably just new and needs breakin.
Take the mags and get a piece of wooden survey stake and push those followers up and down about 50 times to break them in also and that will save you lots of grief.

If it didn't lock back, check for excessive drag on bolt.
If bolt is free and moves easily, check the alignment between the gas block and barrel.
When you remove the gas block, there should be a tale-tail soot ring showing where the block was sitting.
If it's off, center it and try again.

Get back after you try this and we will go from there.

This is exactly why I built my lower but let the "professionals" build my upper.

Thanks Eric @ Blackstone!

Never a FTF and dead on balls accurate.

Take it to Eric if you dont get it fixed. He works with ARP barrels everyday and will get you fixed up.

That is my 2 cents.

Thank you Sir!!!

^^^^^^ Nailed it!

I cringed when I saw it. Now I wonder how many people will google a similar problem and run across that post and not read the replies after it. I can only imagine their confusion when they start trying to buy a SPC1 or SPC2 specific bolt. LOL