Gmtech

Is my logic here flawed or am I on the right track

Hi all Wanted to update on the failure to hold open on empty mag issue I was having from my thread on the intro forum..."hello from NW PA" After luckily finding a single ammo that made the gun run properly every time (ejects around 3, feeds next round, and holds open on empty) i tried a bunch of things to make it work with any other ammo. Different mags, removed some buffer weights, hot handloads, slow motion video appeared to be short stroke. Hear me out on this next part...I closed my seekins gas block full off and installed the carbine buffer spring from my ar15. Slowly opened gas block till bolt would move. At half open the bolt will lock back on empty with any ammo I try now. I should try some different rifle length buffer springs now. I currently have an aero m5 rifle length (A2) tube, buffer, and spring. Technical details r all in the intro post. I can answer those questions here if needed

Yes I'll be interested to see what he has to say...I was just looking at that thread and it appears it may be to small...22" criterion barrels with rifle length gas system and .875 block journal....do u think its a good idea or not to call criterion and see what they have to say

Thanks so far for the input...I went ahead and removed the gas block to check...I can clearly see a faint outline of the gas block opening on the barrel and the barrels gas port is all inside of the outline...so I am confident my alignment is good...then I attempted to check gas port dia. It is larger than .078" but smaller than .085"

I'm 6 months in on waiting for a silencerco omega 300...so I plan on shooting suppressed eventually...would swapping to a regular gas block for now help in the diagnosis any?

It has 30 total rounds...never built my own before...is it to soon to get worked up...how often does simply shooting them eventually work itself out...I will check my block alignment...not sure what I can do about it...criterion dimpled it...the set screws from seekins r tapered so it all just kinda centers itself...right?

When it was ejecting at 3oclock and the bolt was catching on the feed lips it was tossing the brass maybe a foot...switch to the s&b and its tossing it 6 feet or more at 4 o'clock. I'll try full open again...I have gone full open...actually past full open..threaded this seekins "select" adjustment screw out so far when I fired it it damn near blew the adjustment screw out the front of the block..😆

I see lots of talk about opening up the gas port in the barrel but I would think criterion has that figured out and don't think I could bring myself to do it. I did not measure it before installing the block. Changing to an armalite buffer setup would be less invasive and quick

Attaching pic of gas tube halfway to cam pin cutout. I feel like I am lubing the hell out of it. Inside length of buffer tube is 9 and 5/8". Spring has 39 coils and is 12 and 5/8". Weighed buffer on triple beam at 5.2 oz. Buffer is 5.21" long. When pulling charge handle full back there is 0.25" gap between bolt face and bolt stop. The barrel was predimpled by criterion. Gas block screws r tight. Dont see much carbon blowby on barrel just a little bit at base of gas tube where it is in block. Stock screw is not protruding into buffer tube.

I will attempt to answer preliminary checks. Gas block is open 25 clicks (30 is max according to seekins) like stated earlier with one round in mag round is fired..ejects (weakly to 3 oclock) and bolt carrier is hung open by mag feed lips. I worked my way to this agb setting from fully closed. I've been to the range 3 times this week and just this afternoon got it to work perfectly with S&B 150gr .308 SPCE..ejects to 4 o'clock and over the next bench to my right. 150gr rem corelokt, 149gr win m80 7.62, and 165 gr handloads all barely eject and carrier hangs on feed lips. Why does that one round work..I jumped back and forth between ammo with same results

Aero m5 lower Aero m5 LPK Geissele SSAE trigger Magpul miad grip Aero 308 rifle buffer kit for A2 fixed stock Luth ar mba1 stock Aero m5 upper Shoulda got the m5e1 cuz In the end I got Aero m5 enhanced 15" handgaurd Criterion dpms 22" m118 lr barrel Fulton armory bcg that criterion headspace Raptor charging handle Lantac awm 5 round mag

Hi all Just officially joined forum today and wanted to introduce myself. I have been reading threads here for awhile now. Anytime I search something on Google your forum comes up with lots of ideas. I purchased my first ar (5.56) about a year and a half ago and wondered why I hadn't done it sooner. I also have a 6.5cm bolt gun and reload for both. Before I got the 6.5 I was gonna get a 308 rifle but the more research I did and with the goals I wanted to achieve the 6.5 made more sense....but I still wanted that 308. My first shooting experiences were with a 308 and I wanted that nostalgia. I'm an auto technician and troubleshoot and repair mechanical systems so I thought ill build my own ar308...and that is when the troubles started. From my searching I have a very common issue that can be caused by many things. 1 round loaded in mag bolt will not hold open against catch...carrier catches on feed lips Build details to follow