panel77 Posted January 11, 2019 Report Posted January 11, 2019 short version. Poor redneck in need of loud noises. PSA has 18" stainless complete assembled upper with BCG/CH and M-lok and flattop for $400 delivered. sold then for $449 delivered they had this;516445787 https://palmettostatearmory.com/catalogsearch/result/?q=516445787 sold-again. threw them on top of 80% AMT lowers. fail. proprietary POS PSA hang the upper so far over the magwell, butchered one mag almost 1/2" right in the front to get it to feed... okay. fine. go back to AMT, buy AMT uppers, swap everything. bang, bang, clank, bbbbcbcbbc and repeat. every clank is the bolt riding over the top of a new rnd as it tries to get into chamber. all PMAGs and 20 different ones. then through google i found you guys and read 98Z5V posts on the fixes and ive got them all; gas tube barely into cutout-check short buffer springs <11.5"-check >7.625 buffer tube-check buffer weight low: one is 3.85 marked with H, other is 3.88-check wasted 200 rounds going nowhere so far-check. will find 5+buffer and 13.x spring, install correct length tube, check gas port size and increase to at least 070 one has A2 FS, prob gonna keep that way, the Mlok might try to find adjustable gas block-opinions?
Armed Eye Doc Posted January 12, 2019 Report Posted January 12, 2019 Welcome to the forum. Glad you found some answers to your problems. PSA, as well as many others, like to make things proprietary with their 308AR builds. It would be nice to have some standards, but then we would be just another gun forum.
Rsquared Posted January 12, 2019 Report Posted January 12, 2019 Love the short version Panel. That's F-ing hilarious. Sounds like you're on the right track to getting it running. Oh......and welcome aboard.
shooterrex Posted January 12, 2019 Report Posted January 12, 2019 Till your parts come in might I suggest you put the A2 stocked lower on the 18" with the handguards. Mine is an A2 with the handguard and runs. I did buy the lower complete from PSA. I do have the proper gas tube on the way and will change it out when it arrives. Good luck.
panel77 Posted January 12, 2019 Author Report Posted January 12, 2019 I was looking at parts on PSA and asked simply-how long is spring, how heavy is buffer? this is the answer I got; BEST ANSWER: The spring is a standard AR-10 spring length and the buffer tube is the same. The buffer tube is hollowed out aluminum so it's pretty light weight. Think AR-15 just a little bigger. Everything is just ratched up a notch to accommodate the .308/7.62x51 round. Nothing weighs more than what's necessary for a semi-auto .308 rifle... ---------- This is not an answer to the question I asked. =( 98Z5V sent me a PM and gave me encouragement and links-thank you! Just waiting for the mailman now. shooterrex told me to put on the A2 and run it till parts show. Thanks for that but I think I'm gonna wait as range time is rare and distant and expensive. I dont live(anymore) where I can walk out my back deck and let fly.
98Z5V Posted January 12, 2019 Report Posted January 12, 2019 13 minutes ago, panel77 said: I was looking at parts on PSA and asked simply-how long is spring, how heavy is buffer? this is the answer I got; BEST ANSWER: The spring is a standard AR-10 spring length and the buffer tube is the same. The buffer tube is hollowed out aluminum so it's pretty light weight. Think AR-15 just a little bigger. Everything is just ratched up a notch to accommodate the .308/7.62x51 round. Nothing weighs more than what's necessary for a semi-auto .308 rifle... ---------- This is not an answer to the question I asked. =( 98Z5V sent me a PM and gave me encouragement and links-thank you! Just waiting for the mailman now. shooterrex told me to put on the A2 and run it till parts show. Thanks for that but I think I'm gonna wait as range time is rare and distant and expensive. I dont live(anymore) where I can walk out my back deck and let fly. Their spring is nowhere even close to the dimension of an AR-10 operating spring (Armalite part number EA1095). They can order one and compare their parts, if they want to - they'll find out how far off they are. They used to have a member here (Josiah, Jamin's brother), but he hasn't been active in a long time. Weird - you also asked how heavy their buffer was, and they answered (kinda) with the internal depth of a receiver extension- without giving a measurement. Their receiver extension should be 7 5/8" internal depth, not "kinda" or "close" but exactly - but that's not what they make. Their buffer should be 5.4oz, but it's 3.8oz. Food for thought, once again, PSA. Soak up the information, and fix your large frame ARs... if you want.
shooterrex Posted January 12, 2019 Report Posted January 12, 2019 That wasn't much of an answer from PSA. Keep forgetting not everyone has access to a place to shoot. Again good luck with the guns. They will work eventually.
panel77 Posted January 12, 2019 Author Report Posted January 12, 2019 Was going to attach vid but it was over 180mb it was a slomo anxious to get to my saturday project, all this information has me hopeful!
panel77 Posted January 12, 2019 Author Report Posted January 12, 2019 FYI, armalite is out of the $6 spring but https://dsgarms.com/armea1095 has it in stock for $8 and the PSA buffer was 3.88oz sooo heavy.... oh, yeah, sarcasm.
panel77 Posted January 13, 2019 Author Report Posted January 13, 2019 (edited) so pulled the gas block on both uppers. my pin set a little too wide but I got it narrowed to between 0.0735-0.0750 for the gas port. What should i drill it to? one barrel is stainless. Both are PSA Edited January 13, 2019 by panel77
98Z5V Posted January 13, 2019 Report Posted January 13, 2019 Gas block diameters on both at .750"? 18" midlength gas on both barrels? That one I worked on was 18" midlength gas, .750 gas block diameter on the barrel, and I had to take the gas port to 0.085" to get it to run great.
panel77 Posted January 14, 2019 Author Report Posted January 14, 2019 6 hours ago, 98Z5V said: Gas block diameters on both at .750"? 18" midlength gas on both barrels? That one I worked on was 18" midlength gas, .750 gas block diameter on the barrel, and I had to take the gas port to 0.085" to get it to run great. yep-both barrel at gas port are 0.7500 both ports the same at between 0.0735-0.0750 so going straight up to 0.0780 should be zero issue. I didnt buy an adjustable gas block. got the A2 on one and small fixed block on the MLOK. both are 18" MLOK is 18, stainless and 3/4 at the port A2 is 18, standard, and 3/4 at the port.
98Z5V Posted January 14, 2019 Report Posted January 14, 2019 Start at drilling them to 0.081". You might need to go up to 0.085", like I did. My numbers are with an Armalite AR-10 Carbine Gas tube, which is longer than what PSA sends these rifles out with. Fix that gas tube first.
panel77 Posted January 14, 2019 Author Report Posted January 14, 2019 (edited) Tubes in the mail from rainier uppers in pieces waiting for parts along with 5.4 buffers and correct arma springs Edited January 14, 2019 by panel77
98Z5V Posted January 14, 2019 Report Posted January 14, 2019 You can go ahead and drill that gas port to 0.081". That will be a #46 drill bit. You'll have to do that anyway. Have a #44 ready.
panel77 Posted January 20, 2019 Author Report Posted January 20, 2019 went conservative 0.0785 from 0.073 13.5" spring from 11.25 2 quarters=7.625 buffer tube from 7.825 5.48oz buffer from 3.xx rainier gas tube was supposed to be the right length BUT came as 393mm(~15.5") and my old one was 298mm((~11.73") and should have been something like 305 or 310-i dont know exact but in all cases-waiting for the mail again.... 18" barrel from PSA came with the shorter 298 the part number in google sent me to the rainier site which turns out arrived in the aforementioned 393mm so now I have to return and get the right one from somewhere. maybe should be 12"?
panel77 Posted January 20, 2019 Author Report Posted January 20, 2019 Bummer-that armalite part number gave me the rainier website and when I called-i got sent the ~15" version. I think it was this one which is the right price for what I paid and it came as 15" https://www.rainierarms.com/armalite-ar10-gas-tube-carbine/ this site showed the dimension; https://www.cheaperthandirt.com/product/lbe-unlimited-ar-10-mid-length-gas-tube-stainless-steel-argt308-765857617589.do?from=Search&cx=0 and when I went direct to the site-they didnt show the dimension, but it was ~$4 cheaper https://www.lbeunlimited.com/product/argt308/ these guys are out of stock and are apparently the longest with a posted dimension; https://dsgarms.com/arm10007005 since mine was 11.75, im going to try the 12.06 and leave it at that since the DGS at 12.125 is not available and honestly, may be too long based on a tentative measurement for how far the PSA stuck into the moon.
98Z5V Posted January 20, 2019 Report Posted January 20, 2019 5 hours ago, panel77 said: since mine was 11.75, im going to try the 12.06 and leave it at that since the DGS at 12.125 is not available and honestly, may be too long based on a tentative measurement for how far the PSA stuck into the moon. You have a barrel that has a gas port drilled in it, in a position that the barrel maker thinks is okay for both types of gas tubes. Your gas port is in your barrel in a "compromise position." You are correct that the Armalite AR-10 Carbine will extend into the cam pin cutout just slightly more than half way. If does not interfere with the gas key on the carrier, and will not bottom out in the gas key. Your other choice is a custom-lengthed gas tube from White Oak Armament. Thank your barrel maker for following the brilliant idea of a gas port location that is not DPMS-based, and not Armalite-based. They're the ones that put you in this situation.
98Z5V Posted January 20, 2019 Report Posted January 20, 2019 5 hours ago, panel77 said: since the DGS at 12.125 is not available and honestly, may be too long based on a tentative measurement for how far the PSA stuck into the moon. Your number is off, making it appear even worse. 12.125" would be 12 1/8". It's not 12 1/8" long - it's 12 1/16" long. 12.0625"...
panel77 Posted January 20, 2019 Author Report Posted January 20, 2019 DErrrrrr.. so what happens when you post late at night with a sick kid, your brain is not connectted. you are correct!!! I had Joe Bobs tell me midlength doesnt matter and since its bent, the length isnt precise. I will wait till rainier gets back to me or call them Monday and see if their midlength is 12 and we can swap back. otherwise will order from LBE direct and get a stockpile. BTW-my POS PSA gas tube was INSANELY fouled on the outside on both ends and its got less than 300 through it.
98Z5V Posted January 20, 2019 Report Posted January 20, 2019 (edited) I could get further into this - in using AR15 gas tubes in a .308 AR, and the bend being incorrect, but it's a pain in the ass. Basically, the bend isn't correct, using an AR15 gas tube on a .308AR. I posted pics of this awhile ago. Anytime you're using an AR15 gas tube on a .308AR, you're making a compromise. It's a height-over-bore thing. Edited January 20, 2019 by 98Z5V
panel77 Posted January 21, 2019 Author Report Posted January 21, 2019 yep. will just wait for rainier tomorrow and if they dont have a 12, the will order from LBE and return to apparently rifle length to Rainier
panel77 Posted January 25, 2019 Author Report Posted January 25, 2019 so rainier has the correct 12.xx in stock and mistakenly sent me the 15.5" They are awesome and sent me a label and sending me the right ones. stocked up for future builds.
panel77 Posted January 27, 2019 Author Report Posted January 27, 2019 (edited) and as you so accurately figured out-these guys show their barrel as a 0.082 gas port hole. https://www.bearcreekarsenal.com/b308msc18110-p so I went brave and used a 0.080 drill on mine without testing any prior size. I figure with whatever runout in my drill, im pretty super close to that and under a little is better than the ~0.073 i started with Edited January 27, 2019 by panel77 link
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