PNMRED Posted January 31, 2022 Report Share Posted January 31, 2022 (edited) Hello Gentlemen, I am humbly asking for help. I have an LR-308 style rifle assembled with an Aero Precision M5 upper with a Ballistic Advantage Modern series 20" in .308 with a .750" journal. I measured and it does have the shorter AR-15 rifle length gas length and the end of the gas tube does sit halfway in the cam cutout in the upper. The receiver extension, spring, and rifle buffer came in a "Ar10" rifle kit from Stag Arms. I do know that the buffer is slightly shorter than an AR-15 rifle buffer and it does weigh 5.5 ounces. The black carbine in the other picture is the first LR-308 rifle I have assembled and it worked flawlessly from the first round and has just under 600 rounds through it now. It is a Davidson Defense "Goblin" upper receiver witha 16" Bushmaster heavy barrel with a .750 journal, and the "slightly longer than AR-15" Armalite midlength gas system. It has a VLTOR RE-10/A5SR receiver extension with an "extra power" Davidson Defense recoil spring that claimed it was correct for the VLTOR extension, and a 4.4oz AR-15 carbine length buffer. To reiterate the black rifle runs like a top. The FDE rifle started with an .086" gas port and I have opened it step by step and it now sits with a .096" gas port. Initially it wouldn't even eject and slow mo video showed that the bolt would only come back enough so just a 1/4 to a 1/3 of the ejection port was actually open. It got a little better with each step and now with the .096" port it will lock back on an empty magazine but only 1 out of 10 times. I have 3 brands of magazines, ASC, C Products Defense, and Magpul. All ammo has been "NATO spec" ZSR brand from Turkey. Now when I swap the uppers and lowers between the 2 rifles, they work flawlessly. I mag dump them and they both lock back on empty magazines just fine. My next step in troubleshooting was to try a different gas block. It has Bushmaster "slant nose 308" gas block, and have checked several times for alignment. Nothing seems wrong but I am getting the impression that the 20" upper just isn't sending enough energy to the bolt to overcome the rifle buffer system and I want to try other steps before I open up the gas port even more. I am sure I'm leaving out stuff so I apologize in advance. Edited January 31, 2022 by PNMRED Quote Link to comment Share on other sites More sharing options...
PNMRED Posted January 31, 2022 Author Report Share Posted January 31, 2022 To clarify, I'm not against opening it up more I just wanted to seek advice from a more knowledgeable group before I take that step. Quote Link to comment Share on other sites More sharing options...
PNMRED Posted January 31, 2022 Author Report Share Posted January 31, 2022 I haven't measured the "rifle" recoil spring so I guess that may be a culprit. Spring material and heat treatment aside, are the Armalite ea-1095 dimensions: .072" wire diameter, 34 coils, 13.750" relaxed length, 2.448" compressed length? Quote Link to comment Share on other sites More sharing options...
PNMRED Posted January 31, 2022 Author Report Share Posted January 31, 2022 I have checked over and over to detect signs of energy robbing symptoms like excessive friction between moving parts, and see nothing unusual. Quote Link to comment Share on other sites More sharing options...
Czgunner Posted January 31, 2022 Report Share Posted January 31, 2022 Which BCG are you using? Verified the gas keys screws aren't broken/loose? Quote Link to comment Share on other sites More sharing options...
PNMRED Posted January 31, 2022 Author Report Share Posted January 31, 2022 (edited) Thank you for chiming in. I have 3 Davidson Defense nitrided specials and 2 I assembled from Bushmaster chrome lined carriers and Faxon bolts. I squared the gas key face and sealed with permatex on the ones I assembled. I tested all with soapy water and compressed air. Now they all work in the black carbine, and they all work when i swap uppers between the 2. I measured the buffer spring in the 20" rifle and the wire diameter is 1.99mm thick, relaxed length is 12.75", # of coils is 35. It looks identical to Aero Precision APRH100192C, but from what understand is not even close to Armalite ea1095. Edited January 31, 2022 by PNMRED Quote Link to comment Share on other sites More sharing options...
PNMRED Posted February 2, 2022 Author Report Share Posted February 2, 2022 Got an ea1095 on the way from Slash's Heavy Buffers. Fingers crossed Quote Link to comment Share on other sites More sharing options...
DNP Posted February 3, 2022 Report Share Posted February 3, 2022 Let’s hope it’s that easy. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted February 4, 2022 Report Share Posted February 4, 2022 On 1/31/2022 at 8:53 AM, PNMRED said: I haven't measured the "rifle" recoil spring so I guess that may be a culprit. Spring material and heat treatment aside, are the Armalite ea-1095 dimensions: .072" wire diameter, 34 coils, 13.750" relaxed length, 2.448" compressed length? I've seen that Stag spring first-hand, and it's a very stiff bastard. Put in an Armalite EA-1095 spring or a Sprinco Red spring, and see how it does - those two springs will perform the same, so just grab what's in stock somewhere. For that EA-1095 spring, that's the real Armalite part number, so so buy anything else that you can't comfirm is the actual, real Armalite part. Well, besides that Sprinco Red. Everything else is where it needs to be for your recoil system. Buffer should be 5.200" long and 5.4 oz. Receiver extension internal depth should be 9 11/16" deep, from the back of it inside the tube, out to the top edge. Quote Link to comment Share on other sites More sharing options...
billymagg Posted February 6, 2022 Report Share Posted February 6, 2022 On 1/30/2022 at 6:56 PM, PNMRED said: Hello Gentlemen, I am humbly asking for help. I have an LR-308 style rifle assembled with an Aero Precision M5 upper with a Ballistic Advantage Modern series 20" in .308 with a .750" journal. I measured and it does have the shorter AR-15 rifle length gas length and the end of the gas tube does sit halfway in the cam cutout in the upper. The receiver extension, spring, and rifle buffer came in a "Ar10" rifle kit from Stag Arms. I do know that the buffer is slightly shorter than an AR-15 rifle buffer and it does weigh 5.5 ounces. The black carbine in the other picture is the first LR-308 rifle I have assembled and it worked flawlessly from the first round and has just under 600 rounds through it now. It is a Davidson Defense "Goblin" upper receiver witha 16" Bushmaster heavy barrel with a .750 journal, and the "slightly longer than AR-15" Armalite midlength gas system. It has a VLTOR RE-10/A5SR receiver extension with an "extra power" Davidson Defense recoil spring that claimed it was correct for the VLTOR extension, and a 4.4oz AR-15 carbine length buffer. To reiterate the black rifle runs like a top. The FDE rifle started with an .086" gas port and I have opened it step by step and it now sits with a .096" gas port. Initially it wouldn't even eject and slow mo video showed that the bolt would only come back enough so just a 1/4 to a 1/3 of the ejection port was actually open. It got a little better with each step and now with the .096" port it will lock back on an empty magazine but only 1 out of 10 times. I have 3 brands of magazines, ASC, C Products Defense, and Magpul. All ammo has been "NATO spec" ZSR brand from Turkey. Now when I swap the uppers and lowers between the 2 rifles, they work flawlessly. I mag dump them and they both lock back on empty magazines just fine. My next step in troubleshooting was to try a different gas block. It has Bushmaster "slant nose 308" gas block, and have checked several times for alignment. Nothing seems wrong but I am getting the impression that the 20" upper just isn't sending enough energy to the bolt to overcome the rifle buffer system and I want to try other steps before I open up the gas port even more. I am sure I'm leaving out stuff so I apologize in advance. In the meantime, buy you a box of .308 ammo, and leave that Turkish 7.62 surplus for fun when you actually get your rifle running.. are you saying this top end runs well on your first build lower??? and that your first build upper runs fine on this lower?? Quote Link to comment Share on other sites More sharing options...
PNMRED Posted February 6, 2022 Author Report Share Posted February 6, 2022 On 2/4/2022 at 3:24 PM, 98Z5V said: I've seen that Stag spring first-hand, and it's a very stiff bastard. Put in an Armalite EA-1095 spring or a Sprinco Red spring, and see how it does - those two springs will perform the same, so just grab what's in stock somewhere. For that EA-1095 spring, that's the real Armalite part number, so so buy anything else that you can't comfirm is the actual, real Armalite part. Well, besides that Sprinco Red. Everything else is where it needs to be for your recoil system. Buffer should be 5.200" long and 5.4 oz. Receiver extension internal depth should be 9 11/16" deep, from the back of it inside the tube, out to the top edge. I'm glad you said that about the Stag spring, because I took out all my recoil springs from all my builds and the Stag spring was easily the stiffest of them all, even more so than my AR9 blowback springs. All the dimensions measured out fine, unfortunately the ea1095 was supposed to be delivered yesterday but USPS dropped the ball. As far OEM authenticity, is Slash's Heavy Buffers a legit source? That's where I ordered mine and I emailed them and they claim it's an OEM Armalite ea1095 spring. I've never done business with them before. Quote Link to comment Share on other sites More sharing options...
PNMRED Posted February 6, 2022 Author Report Share Posted February 6, 2022 13 hours ago, billymagg said: In the meantime, buy you a box of .308 ammo, and leave that Turkish 7.62 surplus for fun when you actually get your rifle running.. are you saying this top end runs well on your first build lower??? and that your first build upper runs fine on this lower?? I Included the cartridge box pics for clarity. From what I understand SAAMI .308 win is hotter than 7.62NATO? I was wanting it to function with "NATO" fmj's before I try commercial .308. Personal preference I'd rather control/throttle the energy going in to the system. Yes when I swap the uppers/lowers between the 2 builds, they function flawlessly. I don't know the port size of the black "carbine". I just ordered the parts and slapped it together and it's run without a hiccup even before the A5 setup with the standard DPMS buffering system. I've pinned the gas block (War Machine WarBlock 75) on the black "carbine" and am not wanting to remove it if I don't need to. Quote Link to comment Share on other sites More sharing options...
unforgiven Posted February 6, 2022 Report Share Posted February 6, 2022 I've used Slash's Heavy buffer/spring kit in 20" 5.56 and RRA .308 Standard operator without issue. Armalite recoil system in all large frame rifles. Running suppressed without adj. gas block. Just my 2 mags Quote Link to comment Share on other sites More sharing options...
PNMRED Posted February 6, 2022 Author Report Share Posted February 6, 2022 4 minutes ago, unforgiven said: I've used Slash's Heavy buffer/spring kit in 20" 5.56 and RRA .308 Standard operator without issue. Armalite recoil system in all large frame rifles. Running suppressed without adj. gas block. Just my 2 mags Duly noted sir, I appreciate your input! Quote Link to comment Share on other sites More sharing options...
98Z5V Posted February 6, 2022 Report Share Posted February 6, 2022 30 minutes ago, PNMRED said: As far OEM authenticity, is Slash's Heavy Buffers a legit source? Oh Hell Yes. That's the best source you'll ever find for recoil system information anywhere, no matter what. What he does and how he does it is what made me do my deep-dive into recoil systems. There's no better resource anywhere for recoil system information, hands down. Quote Link to comment Share on other sites More sharing options...
PNMRED Posted February 6, 2022 Author Report Share Posted February 6, 2022 1 minute ago, 98Z5V said: Oh Hell Yes. That's the best source you'll ever find for recoil system information anywhere, no matter what. What he does and how he does it is what made me do my deep-dive into recoil systems. There's no better resource anywhere for recoil system information, hands down. That is a relief! Thanks! Quote Link to comment Share on other sites More sharing options...
PNMRED Posted February 6, 2022 Author Report Share Posted February 6, 2022 I'm assuming the EA1095 will get delivered Monday. I will update this thread with results as soon as I test. With my work hours I'm just not sure if it will be Monday though. Quote Link to comment Share on other sites More sharing options...
PNMRED Posted February 12, 2022 Author Report Share Posted February 12, 2022 Ordered a Sprinco "Red" today from Primary Arms because USPS lost my springs from Slash's Heavy Buffers. Quote Link to comment Share on other sites More sharing options...
blue109 Posted February 12, 2022 Report Share Posted February 12, 2022 Interested to see if the spring changes anything. My 16" rifle length gas gun was running really inconsistent and short stroking alot. I threw almost a whole new guns worth of parts at it until I finally just whored the gas port out to something around .105 (don't remember exactly, I have a thread in here) and it's flawless 100% of the time now. Sprinco and KAK heavy buffer were purchased during the troubleshooting process so I left them in, but it runs if the factory parts fine as well. That black rifle is a sexy beast. Nice work. Quote Link to comment Share on other sites More sharing options...
billymagg Posted March 1, 2022 Report Share Posted March 1, 2022 On 2/12/2022 at 12:56 PM, PNMRED said: Ordered a Sprinco "Red" today from Primary Arms because USPS lost my springs from Slash's Heavy Buffers. So are we running now??? Quote Link to comment Share on other sites More sharing options...
PNMRED Posted March 3, 2022 Author Report Share Posted March 3, 2022 Howdy folks! So USPS finally delivered my EA1095's on February 16th. I tested on the 19th and the bolt would lock back on a empty bag reliably with all my mags. Unfortunately it would not chamber a 2nd round. The failure to feed malfunctions appear to be over gassing now where the new cartridge (towards the mouth of the casing) would get pinned between the bolt and the feed ramp of the barrel extension. Iphone Slow mo also appears to show excessive bolt speed. So i ordered an adjustable gas block when i got home that day. Unfortunately i suffered a back injury the next day and have been preoccupied dealing with that. I'll keep you guys posted when I hit the range next. Quote Link to comment Share on other sites More sharing options...
Armed Eye Doc Posted March 5, 2022 Report Share Posted March 5, 2022 I hope your back is improving. Post a picture of the feed ramps and chamber. It could be a tolerance stacking issue causing the misfeed. It could also be a magazine issue. Quote Link to comment Share on other sites More sharing options...
FALPhil Posted March 9, 2022 Report Share Posted March 9, 2022 On 2/6/2022 at 1:39 PM, PNMRED said: From what I understand SAAMI .308 win is hotter than 7.62NATO? You understand incorrectly. But, you are not alone. This myth has been perpetuated by people who have repeated what they have read in gun rags where zero research was done. SAAMI actually says that the two are interchangeable. You can check it on their website. Meanwhile, you can read some referenced research. https://www.docdroid.net/shd8/the-truth-about-308-win-and-762-nato-pdf Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted March 9, 2022 Report Share Posted March 9, 2022 On 3/8/2022 at 8:03 PM, FALPhil said: You understand incorrectly. But, you are not alone. This myth has been perpetuated by people who have repeated what they have read in gun rags where zero research was done. SAAMI actually says that the two are interchangeable. You can check it on their website. Meanwhile, you can read some referenced research. https://www.docdroid.net/shd8/the-truth-about-308-win-and-762-nato-pdf ^^^ This post right here needs to be written upon stone for the ages to come. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted March 9, 2022 Report Share Posted March 9, 2022 Read this first before you want to pin that, for all the ages to come... https://sofrep.com/news/whats-difference-308-winchester-ammo-7-62-nato-not-think/ Quote Link to comment Share on other sites More sharing options...
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