Albroswift

That is the kicker, isn't it. Not being there in person, the only difference between the 1st and 2nd is the position of the charging handle. Please verify: When you charge the first round, are you dropping the bolt with the bolt release or pulling the charging handle all the way back and dropping it. Second round, pulling the CH all the way back I assume. Something to try, in the interest of science, 4 things: 1.) First round will the forward assist move the BCG forward after chambering the round. 2.) Second round: lower the CH to the bolt catch, engage the bolt catch, lower the CH all the way down, drop bolt w/ BC 3.) Second round slowly lower the CH a little past the bolt catch before releasing it. 4.) First round "Rubber Band" it, pull the CH as far back as possible and let it drop fast from full back position. Maybe these checks will point us in a particular direction. Also, without the recoil spring,( but with buffer )how much space do you have between the bolt catch and the face of the bolt? #10 on the waterboarding thread. 10.) BCG Clearance at the ears and bolt stop AL

Cheap Chinese aluminum meets a Henry Ford spanner, what's not to like. And he had the balls to post the photo, make me wish I had taken pictures of all my fuk ups instead of just the cool stuff! What a thread that would be, probably run out of storage space on the server!

I don't think the upper could do that to headspace, only the barrel extension lugs, the bolt lugs, and the chamber. ARs headspace without the upper?

@Fmtreading Couple tools you may want to invest in. The No Mar blocks hold the upper very secure in a big vise, you can get plenty of torq on a upper with these in this flat configuration. Also hold the upper pinned in the vertical orientation for assembly and optics and such. Also barrel nut wrench from Spikes, 100 times stronger then the pot metal "armorer tool"

alignment: gas key should line up with alignment pin in barrel extension. With the bolt all the way seated will the key line up?

Yes, exactly what I'm running in my 12.5 in ar308. Better yet replace the entire tube, buffer, and spring with the Armalite 7-3/4" setup when back in stock.

@Fmtreading To eliminate the lower, Clean the chamber and extension really good and try charging the upper without the lower attached. Round will probably be sticky, probably need to mortar it out but shouldn't be too hard. (Mortar it onto something softer then concrete floor. Or use a rubber mallet on the charging handle, that works for me) f you had a go gauge that would be even better then a live round. We are trying here to determine how difficult it is for the bolt to rotate into and out of battery. New 308 chambers can be tight. Different ammo can make a big difference. A lot of rounds that are difficult to extract manually fire and eject just fine, especially in a new chamber. Hopefully you didn't damage the barrel extension with the reaction rod and all that torque. The scratches look like drag marks from the lugs on the barrel extension, wouldn't worry about them. Probably take some time, be safe and keep after it. PS after converting g to oz I think you are going to find out that buffer is way too light. need 5.4 oz 153 g

@billymaggYou know what I missed, first thing ALWAYS, 1 round in a magazine, insert magazine, charge and fire. If it doesn't lock back, no reason to go any further. @Fmtreading may have second round coming out part way and slamming back in. Slamming spent brass back in the chamber will make for a sticky situation. The photos he shows are live rounds, no fired cases.

Lock closed or open? Second round in chamber and fired?

Also, I recognize the handguard in the photo, ditch it, out of spec piece of junk. Rail to tight to the outside diameter of the guard to install any accessories that have to slide on from end. (Also, I recognize the barrel nut, and the broken wrench, been there, done that, got the tee shirt!) Use ant seize or MCARBO grease. If you want a budget handguard, one place I like is ar15handguard.com. Sam Pan is great on customer service and everything I've gotten there fits nicely. Luck.

Helllo, @Fmtreading More photos of the upper, and... Upper only stripped, does the charging handle move freely. Upper/ BCG/ charging handle no barrel, do the parts reciprocate freely. Add barrel, repeat No internals, upper an lower and charging handle only, repeat... You see where I'm going with this, one part at a time until you hit the rock. I bet you wiped out your upper, but like you say hard to diagnose. As some say areound here, stick with it give us all the info we ask for and we'll get her running.

+1 on the VG-6 series. Shop around, surprising the price range.

I love coming home and finding gun parts in the mailbox

Try it and report back! First make sure the spring is right side up. Maybe lighting the disconnector? Millspec? I have had this problem with 2 blowback. 40sw, pistol and carbine, and pistol length ar15. Different combinations of springs and buffers until it goes away is my usual approach.

I run into that once in a while, I think, sometimes, its bolt slam bouncing the disconnector. Milspec fcg? Happens on lighter guns, guns with solid buffers, blowbacks with heavy solid buffers, bottom half of the magazine when top half no problem. But then, who knows?

Sneak Peek, 1911 Commander 45 in SS. Just about got everything rounded up.

Like I said, cant reproduce in the frame or a jig. Even trying to push/pull up/down on the on the disconnector or front of the trigger bar. Next test 1 round no mag, fire, open while holding trigger. (First thought of 2 rounds fire one, open while holding trigger back, uhh, what could possibly go wrong with that)

Hello, All Shorty 7-1/2" AR15 What could possibly cause a mill spec trigger to act as a binary? Only when live firing, unable to reproduce in frame or trigger jig. Also, this trigger came out of another AR that I upgraded, worked 5X5 in that platform. Single round BCG lockback test passes. Didn't try one round no magazine. I thought I might have had a couple a while back out of 100 rounds, not even sure if they were slams or binary or finger bounce. 4 oz buffer and Sprinco white hot Put a lighter spring and buffer (Mill Spec AR15 damage industries) Pull the trigger, bang. Hold the trigger back as long as I want, release, bang. Pretty cool but... Went to the lighter spring because pistol would cycle 40 gr and 62 gr but not 55 gr. It now works with the 55's, but not expecting this. Going to try with a different FCG.

We are here to help, and have a hell of a lot of fun doing it!

Take a look at this thread. Fill in as many of the blanks as possible .

It would be real commitment if I lived in a condo!

So range report The 1911A1 fed the 230gr ball ammo like a champ, spring a little weak maybe after firing a couple rounds slide was slamming the guide rod head into the recoil shoulder hard enough to leave marks on the head, added a rubber recoil bumper ran out several clips 10mm had a light primer strike about 50% of the time. Shot really nice other then that. In my opinion, light primer strikes are usually caused by anything but the spring, so looked it over really hard, put a longer hammer spring in anyway, looked it over really really hard, seems like the hammer was just nicking the slide on the extractor side. Removed some material and polished back up, ready for range test 2. Edit, couldn't wait. Torched a few off in the basement, seems good to go!

OK, ready for the range!

Nice!

Noreen, 30-06 and belted magnum AR's BN36X3