Albroswift

Opened that baby up to .087, put the Armalite recoil parts back on, too much gas. Cranked the Seekins AGB down to about 2.5 turns, shooting sweet. 4 different factory loads in the 120-150gr range, all good ran out about 60 rounds 100% reliable. Tuning question for someone smarter then me: Ejection pattern 1:00 Cranked in gas block a little more, bit by bit all the way to no LRBHO and brass falling right out onto the shooting bench but could never get past 1:00. Went the other way until signs of too much bolt speed ditto. Maybe go to a 6.8oz buffer and a little more gas? Dual ejector? Or no big deal...

@aadavis94 Friend was shooting a new 6.5 CM build, exhibiting similar problems. Armalite buffer system, Toolcraft bolt. Seekins adjustable gas block. Even with the heavy buffer system, we still had to back the gas block down about 50% before 100% reliable. (port hole .087, midlength gas)

Bummer about the stuck ejector, either bent it or embedded something foreign in there. I would first put some oil in the hole and then try to push the ejector in against the spring see if you can get it to move in and out. Hopefully it will go shooting across the shop and land near the last one. Hopefully you have a spare. What are you using to compress it and hold in place while you pin it? Bolt really needs to be held secure during this operation. There is a thread on this forum somewhere that has all the roll pin sizes, or order one. I use Damage Industries for little parts like that. http://damageindustriesllc.com/store/index.php?route=product/product&product_id=335&search=ejector+pin My preferred install method is tape the pin to a nail set, VERY light bevel grind on the leading edge and it starts straight and installs easily. Same technique with the gas block pin. Good luck, we'll get this thing shooting if it kills us!

Interesting point. On the other hand, you are not fitting the upper to the lower with the jig. As far as just milling the FCG pocket is concerned, seems there is quite a bit of tolerance. Haven't had any issues.

That is correct, but so far i haven't had an issue with the several I have done. All have aligned perfectly with the uppers takedown holes. Didn't even know mis-alignment was a thing. One AR40, one AR308, one AR308/6.5CM and several small frame jobs.

I also like the side guide bushing setup of the 5D rather then the center guide. I think I've caught on to why your FCG pocket doesn't connect with your rear takedown pocket, you skip the first guide and just start with the "B" Bushing? That would work the same with the 5D if I started with the #2 guide bushings instead of the #1's. Good luck with the rest of the build, sounds like you can figure it out. Keep posting!

The 5D jig holds the rear of the forging very securely from the extension tube threads only so no pin in the way. Only touches the receiver there and the front takedown pin. Other then that the jigs look similar.

AMT twice and Delta Team Tactical once, look identical function fine for 308's and 6.5's. DPMS low rail clones I think. Maybe got lucky on the DTT, some reports about them never know what you might get. Never had a problem with AMT uppers and AMT 80% 308 lowers Anderson and Aero Precision for the small frame uppers, Anderson forged 80% lowers New Frontier smooth side upper over a 5D 80% lower for the .40 pistol, needed their style with the LRBHO activator in the upper. (Spikes style have the LRBHO device in the lower, have 2 of them) Have a raw AMT upper and a raw Noreen forged 80% lower for the next 308 build, and bunch of Anderson forged 80% lowers laying around from the last sale. I may have a problem....

Forged for me, but in 308's except for Noreen I haven't seen a true forged. "Forged" Billet, but not "Forged" Several different brands of billet 308 80's have that exact same wave cut over the safety and under the takedown with the big shelf on top, assume they are all coming from the same place. Built 2 on that style so far, same as yours, both zero issues.

Almost all the 80 lowers come that way now. I would say ALL but maybe one or two out there don't, haven't seen one though. I understand it was common a while back.

@PaddyMac I noticed the rear takedown pocket does not connect to the FCG pocket like all of mine do or like (most?) factory . Also, just maybe, clamping across the sides like you show puts just enough torque on the side plates that your holes drill at a very slight upward angle, causing that tight fitting safety.

@PaddyMac Looks like you have your jig in the vise oriented the wrong way, at least with the 5D you don't squeeze it that direction, maybe yours is different. Anyway, good work and good photos!

Yes, yes, and yes...

@PaddyMac I'm using the 5D Pro Jig, several lowers running well. Not familiar with the Easy Jig, post lots of pictures please.

@sagebrush OK, Actual photo is looking down on my 12.5" 308 pistol. The tube is the 11-3/8" one I made from a straight rifle length, (Too impatient to wait for White Oak? to get back from the Nat's ) The one on the left in the photo below is mine, factory tube right. Turned it down on the lathe very carefully and even more carefully applied the bend.

@PaddyMac Tight is better then loose. What brand lower and upper? Good luck finding 308AR specs! Post complete build list as you go, or better yet before you buy. The crew here may save you some grief! EDIT 308 or 556 80%?

@sagebrush Looking at that photo I gotta pull the shooter out when I get home and take another look. Gotta be an optical illusion. Gun runs fine BTW. AGB 4.25 clicks.

Looks good. Lets get this thing running!

2nd picture up is mine. All same diameter until "Knob", optical illusion maybe caused by camera flash. Just turns from shiny to rough where it slips into the gas key. Probably caused by fouling from escaping hot gases .

I like the KAK, running them in 3 BCG's so far. https://www.kakindustry.com/kak-bcg-ejector-308 Sprinco has great springs. Also, after loosing a couple I bought the tool https://www.brownells.com/gunsmith-tools-supplies/rifle-tools/bolt-tools/ejector-tools/308-ar-bolt-ejector-tool-prod72380.aspx

You will find a use for the spring and tube when you build your next small frame AR! Pretty sure no one has found a good use for a 2-1/2" 3 oz buffer yet. Maybe we should have a contest.

is this sr25 or armalite? I had a link to the low dpms pattern if you want me to dig it up? DPMS low profile if you have a chance. No hurry, already spent too much this week!

Hey, thanks. Been down the Tiger rock path, ever try to order anything from them? I gave up. Site seems to be set up for someone with a dealer account, can't get anyone on the phone. ABC doesn't seem to have one for 308, maybe I'm missing something. I love the JL Billet but don't want to fuch up such a nice piece. Looking for cheap to practice on. Still looking....

Yes, as in most semis, pistols and long guns, pull the trigger all the way through, release until reset is felt, should be right at the breaking point for follow up shot. Concentration on the reset. This is the first trigger I can remember that pushes my finger off the second stage break point, quite noticeable. There was a second spring in the package but the instructions said that was to increase trigger pull.

Just tried one out this weekend, I like the break but on the reset the trigger bounces my finger back well into the 1st stage zone, I have a CMC 2lb/2lb 2 stage on another build that resets right at the 2nd stage break point. Maybe need a lighter trigger spring?