mordak6actual

Oh and bolt stop is on the bolt face not the carrier. But that's true for both of them.

So I'll put up a few more photos to show what I'm talking about: At left, old carrier, right, new carrier. Bolt was swapped (old bolt w/new carrier, and vice versa). I couldn't get the gun working (or into battery without pushing on the bolt) with the carrier on the left. These are both from Radical FIrearms but the left one has a much narrower channel for the hammer. To answer the question, here are the two springs. One was the original and the other (on the right) is the currently used Heavybuffers.com heavy buffer and spring. Almost a difference of 2 oz. between the two buffers (3.8 vs. 5.7). Springs appeared to be equal length (and were advertised as carbine length .308) The tops of the bolt carriers. Not sure if that is relevant or not. And finally, another picture of the rifle fully kitted out:

So I built a MATEN. I will just summarize from the other posts and condense here to minimize the hunting for the various topics. Long story short, here is what it was doing (in order of the problems from start to finish): - recoil caused the bullet button to self-disassemble (this was an easy fix) - On about the fifth or sixth round, the entire gun seized and refused to go into battery. On takedown/evaluation, the extractor pin had walked and then deformed from the force of the bolt unlocking and rotating into the carrier (diagnosed as bad extractor springs, not providing enough tension to hold the extractor pin in place and keep it from walking) - not going into battery from an open chamber with bolt locked to rear, magazine in well. Hit bolt release, it would not lock up without having to push on the bolt to get it to go into battery - Not going into battery after the first or subsequent shots (same problem, have to push on the bolt to get it to lock up) Here's a picture of the offender: Here's the parts list: MATEN upper/lower matched receiver set RA-SEL-308-16 Rainier Arms Select .308 16" 416R Black Stainless Barrel - DPMS Pattern RF-M-GasTube Radical Firearms Stainless Steel Gas Tube - Mid Length 308-BCG-NiB Radical Firearms Complete Nickel Boron Bolt Carrier Group for .308 with WMD Coating 05-199 ALG Defense Combat Trigger - ACT RF308CARB Radical Firearms .308 Carbine Buffer - 3.8oz DP308-CS-10A DPMS .308 Carbine Buffer Spring - 11.5 Inch LR-01 Black Rain Ordnance Buffer Retaining Pin LR-02 Black Rain Ordnance Buffer Retainer Spring SP0011510031 Seekins Precision Low Profile Adjustable Gas Block .750 Magpul UBR 14" Parallax Tactical fore-end Griffin Armament 7.62 Flashcomp So, here are the things I bought to troubleshoot my issues: - different magazines (Magpul PMAGs to Lancer L7) - another NiB BCG (Radical Firearms) - a Heavybuffers.com buffer and spring So I wanted to take the rifle to Randall from ar15barrels.com to see if he could take a look at the gun but he had a few suggestions to try first. - run it without the buffer pin/spring - try different ammunition - load a single round into the magazine, load from locked back bolt. Repeat 5x. Report back. Nothing he suggested worked. What ultimately fixed it was changing out the carriers (last resort). The old and new BCGs were both Radical Firearms. The old one had a narrower channel where the hammer would fit. The new one had a wider channel. On a hunch I swapped them. Ran the gun with the DPMS carbine buffer spring and original buffer. Gun now runs fine (at least I can shoot the thing like a semi-auto). I'm not sure what was going on at this point. I was thinking the carrier was rubbing against something it shouldn't have been rubbing against, but that doesn't make sense if the hammer is locked downwards, ready to fire. I cranked up the gas port as open as it would go, but my problems started even before firing with the bolt not locking up. With the new carrier, the bolt locks up every time, no problems. I have a set of .308 headspace gauges coming in so I will verify there are no problems, but I figured that if the thing hasn't blown up in my hands after 50+ rounds or so, I should be relatively ok. I also noticed, ironically that I have less problem with 7.62x51 versus .308 (from Freedom Munitions). The surplus 7.62 wasn't causing extraction issues while the .308 was. By now I am running the Heavy Buffers spring and buffer, gas port cracked all the way open, and that seems to be the way to keep the gun working. Just hopefully I am not missing something or overlooking something. All in all this has been a learning experience and a little bit frustrating. Coming from the AR-15 world, things just worked and they were easier to troubleshoot (never had to get into buffer springs, weights, etc.). I guess having a TDP out there as a baseline for manufacturers to ensure compatibility is a good thing and it's unfortunate this never made it to the .308 AR world (or at least have OEMs make their own with regards to receiver dimensions and internal parts, but that's just wishful thinking).

Well, I looked into a heavier buffer, the DPMS buffer/spring I have is labeled for .308. 3.8 oz. seems awfully light for a carbine buffer for .308 so I ordered the spring/buffer combo from Heavybuffers.com in hopes of fixing my issues.

Zombieland Central: South Bay/beach communities, 310.

Well the UBR comes with its own receiver extension ("buffer tube") which should be carbine length from what I understand (worked on my AR-15, used a carbine length spring and all has been well). I cracked the adj. gas block all the way open, lubed the heck out of the bolt, the carrier, and the charging handle. I've done all kinds of crazy things, removed the buffer detent and spring, tried different mags (Lancer L7 and Magpul .308 Pmags), and I only ever feed brass cased ammo through it (combination of Freedom, Aussie surplus and Prvi Partizan so far). I knew I was going to have problems with this gun. At round #8, my ejector pin walked out of the gun mid-cycle and bent against the edge of the BCG from lack of pressure from the ejector springs. I attributed some of the early issues to lube but that bent pin was the start of the craziness. Meanwhile I've now gone through a second bolt/bolt carrier group, tried different mags, lube, etc. Always used the full power ALG spring that came with my trigger, and not lightweight spring. I have to push the bolt to get it into battery on the first shot (load from locked bolt), and every shot thereafter otherwise I get light primer strikes. Hence why I joke I have a bolt action AR.

By request, some gun porn of my MATEN build (and current frustration): MATEN matched receiver upper/lower Magpul UBR Rainier Arms 416R parkerized 16" barrel (midlength) ALG defense trigger AXTS Raptor 7.62 charging handle AXTS Talon 45/90 safety selector Parallax Tactical slim-line fore-end, 14" Griffin Armament 7.62 Flash Comp Seekins adjustable gas block Radical Firearms NiB BCG w/WMD coating Magpul MBUS Pro sights (front and rear)

LOL. I think they only permit semi-harsh language and vague threats now. Supersoakers got banned when it was discovered you could overpressure them and potentially blow up.

Thanks for the awesome welcome guys. ^-^ Not sure what the etiquette is about posting issues (if they should go in this topic or a dedicated topic in a different forum), but I'll list my build here and probably also in the MATEN forum. MATEN upper/lower matched receiver set RA-SEL-308-16 Rainier Arms Select .308 16" 416R Black Stainless Barrel - DPMS Pattern RF-M-GasTube Radical Firearms Stainless Steel Gas Tube - Mid Length 308-BCG-NiB Radical Firearms Complete Nickel Boron Bolt Carrier Group for .308 with WMD Coating 05-199 ALG Defense Combat Trigger - ACT RF308CARB Radical Firearms .308 Carbine Buffer - 3.8oz DP308-CS-10A DPMS .308 Carbine Buffer Spring - 11.5 Inch LR-01 Black Rain Ordnance Buffer Retaining Pin LR-02 Black Rain Ordnance Buffer Retainer Spring SP0011510031 Seekins Precision Low Profile Adjustable Gas Block .750 Stock is a Magpul UBR. Forearm is a 14" Parallax Tactical fore-end, and the barrel device is a Griffin Armament 7.62 Flashcomp. Basically, right now, the rifle is a bolt-action. <lmao>

Hi, New guy in enemy territory (California, or DPROK as I prefer). Built a .308 AR off of a MATEN receiver set, wish they came together as trouble-free as AR-15s. Long time lurker first time poster. Just here to soak up information and get advice. Not new to .308 or even ARs (own a M1A and a couple AR-15s), but .308 ARs are another ball of wax. I like my .308 AR but getting it to work right has been a gigantic headache from day one, it has certainly given me pause about building them versus just buying a factory .308 AR for my next one.

Hi. New guy behind the lines in CA (or the Democratic People's Republic of Kommiefornia as I prefer). Built a .308 AR in May, now about ready to throw it downrange by the barrel. Been lurking on the site for a while just finally decided to post since this is the only real dedicated .308 AR forum out there.