Flabbergasted Posted July 19, 2017 Report Share Posted July 19, 2017 I'm having a failure to feed problem about once or twice every 20 rounds with my AR 308. The bolt rides on top of the cartridge and gets stuck damaging the case. I didn't take a picture myself, but I found a pic of what's happening on the world wide web. I'm not sure what would cause this problem. It happens with all of my pmags and with different types of ammo. Any ideas? Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted July 19, 2017 Report Share Posted July 19, 2017 Can happen when the bolt doesn't go back far enough to catch the next round but the carrier pushes it forward. Does it always lock the bolt back after the last round in the magazine? Quote Link to comment Share on other sites More sharing options...
Flabbergasted Posted July 19, 2017 Author Report Share Posted July 19, 2017 No, It almost never locks back after the last round. I've checked the alignment of the gas block 3 times and find it to be right where it needs to be. Could the BCG be causing the problem? I don't have another one to try out but I was thinking of buying another just to see. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted July 19, 2017 Report Share Posted July 19, 2017 (edited) Barrel Manufacturer ? Gas System ? ( You can also use drill bit index to measure as close as you can the Barrels Gas Port ) Stock type ? Length of inside or Receiver Extension ( Buffer Tube ) Measure length of Buffer Spring & Coil count ? Measure length of Buffer & weight ? Edited July 19, 2017 by survivalshop Quote Link to comment Share on other sites More sharing options...
Dracomeister Posted July 19, 2017 Report Share Posted July 19, 2017 Had a similar issue when I put a new barrel on, the guys on this site figured out my gas tube was too short (by about 3/16") but before they jumped in I went through the whole process of drilling the barrel to spec, installing an adjustable gas block, etc. Check the thread below. They did a great job of diagnosis! New 20" barrel, now it short strokes Quote Link to comment Share on other sites More sharing options...
Flabbergasted Posted July 20, 2017 Author Report Share Posted July 20, 2017 6 hours ago, survivalshop said: Barrel Manufacturer ? Gas System ? ( You can also use drill bit index to measure as close as you can the Barrels Gas Port ) Stock type ? Length of inside or Receiver Extension ( Buffer Tube ) Measure length of Buffer Spring & Coil count ? Measure length of Buffer & weight ? Ballistic Advantage 20" SS rifle gas Buffer tube length: 7-1/4" Buffer spring: ~11-1/8" 26 coill Buffer length: 2-1/2" Weight: ~3.9-4.0 oz Quote Link to comment Share on other sites More sharing options...
Flabbergasted Posted July 20, 2017 Author Report Share Posted July 20, 2017 5 hours ago, Dracomeister said: Had a similar issue when I put a new barrel on, the guys on this site figured out my gas tube was too short (by about 3/16") but before they jumped in I went through the whole process of drilling the barrel to spec, installing an adjustable gas block, etc. Check the thread below. They did a great job of diagnosis! New 20" barrel, now it short strokes Thanks for the info. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted July 20, 2017 Report Share Posted July 20, 2017 21 minutes ago, Flabbergasted said: Ballistic Advantage 20" SS rifle gas Buffer tube length: 7-1/4" Buffer spring: ~11-1/8" 26 coill Buffer length: 2-1/2" Weight: ~3.9-4.0 oz I assume its a Carbine stock system ? Quote Link to comment Share on other sites More sharing options...
Flabbergasted Posted July 20, 2017 Author Report Share Posted July 20, 2017 Yes. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted July 20, 2017 Report Share Posted July 20, 2017 45 minutes ago, Flabbergasted said: Ballistic Advantage 20" SS rifle gas Buffer tube length: 7-1/4" Buffer spring: ~11-1/8" 26 coill Buffer length: 2-1/2" Weight: ~3.9-4.0 oz Need the internal depth of that, man. Also, something isn't right with that spring. Seems pretty close to AR15 Carbine length, but the coil count is way off. Quote Link to comment Share on other sites More sharing options...
Flabbergasted Posted July 20, 2017 Author Report Share Posted July 20, 2017 1 hour ago, 98Z5V said: Need the internal depth of that, man. Also, something isn't right with that spring. Seems pretty close to AR15 Carbine length, but the coil count is way off. Inside depth is 7". The recoil spring is definitely different from an AR 15 spring. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted July 20, 2017 Report Share Posted July 20, 2017 Spring Coil count is a little off , should be 29 coils ( every single ( real ) DPMS Buffer spring I have counted has been 29 ), I count 27 Coils on that spring , you are close, also looking at that spring it looks out of shape ,could probably be weak . Hand loads or Factory ammo ? What Magazine Brand ? Quote Link to comment Share on other sites More sharing options...
Flabbergasted Posted July 20, 2017 Author Report Share Posted July 20, 2017 2 hours ago, survivalshop said: Spring Coil count is a little off , should be 29 coils ( every single ( real ) DPMS Buffer spring I have counted has been 29 ), I count 27 Coils on that spring , you are close, also looking at that spring it looks out of shape ,could probably be weak . Hand loads or Factory ammo ? What Magazine Brand ? All factory ammo. Federal GM Match, fusion, perfecta, and others. It happens with all types. Mags are 20 round Magpul mags. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted July 20, 2017 Report Share Posted July 20, 2017 I don't like the looks of the Buffer Spring , not saying thats your issue , but it just looks limp , could possibly be binding. Try different brand Mag , DPMS's metal or Lancer L7. Are the MagPul's Gen 3 Mags ? Another thing that could help is a Armalite AR 10 Mag Catch , it has a larger Pad to hold the Mag in place more securely .also the threaded stem is longer for Receivers that are wider .( bottom ) Quote Link to comment Share on other sites More sharing options...
Flabbergasted Posted July 21, 2017 Author Report Share Posted July 21, 2017 12 hours ago, survivalshop said: I don't like the looks of the Buffer Spring , not saying thats your issue , but it just looks limp , could possibly be binding. Try different brand Mag , DPMS's metal or Lancer L7. Are the MagPul's Gen 3 Mags ? Another thing that could help is a Armalite AR 10 Mag Catch , it has a larger Pad to hold the Mag in place more securely .also the threaded stem is longer for Receivers that are wider .( bottom ) I'll have to get some other brands of mags. I'm not sure if the pmags are gen 2 or gen 3s. I'll look into that mag catch you mentioned. If it's not the recoil system or the mags or mag catch, what else could it be? The only other thing I can think of is the gas port size. Quote Link to comment Share on other sites More sharing options...
DNP Posted July 21, 2017 Report Share Posted July 21, 2017 Would it even be the mag catch? If it's not getting a full stroke it's either the recoil system or the gas system. Replace the spring. Check that the gas tube is the proper length...there's info on that all over this place-check the thread Draco posted If those don't clear it check the gas port size. Drill bits work good for determining the size of the hole in your barel and there's lots of good stuff from Survival Shop, Washguy, 98 and others. the tube and the gas port can be checked without spending a dime. You can probably post a photo of the inside of your upper and let us know what drill bit fits in the hole...the gurus here can go nuts with info about that. It smells like they suspect your spring at the moment. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted July 21, 2017 Report Share Posted July 21, 2017 (edited) On 7/19/2017 at 11:00 AM, Flabbergasted said: I'm having a failure to feed problem about once or twice every 20 rounds with my AR 308 My thinking is , if it was the Gas Tube , Port size or Buffer Spring ( that Buffer spring is suspect also ) , you should see an issue with the action more often. I have changed my thinking on the Gas Tube penetration also , my 20" HB has never had an issue & I just gave it a look over & found this , in the photo below . Not saying its not needed to be in the middle of the Cam Pin cut , because it would depend on Gas port size , Gas system length & other factors . 5 hours ago, Flabbergasted said: I'll have to get some other brands of mags. I'm not sure if the pmags are gen 2 or gen 3s. I'll look into that mag catch you mentioned. If it's not the recoil system or the mags or mag catch, what else could it be? The only other thing I can think of is the gas port size. Start with the different Mag . , Magpul has two LR PMags , the original ( I guess you could call it the first Gen. ) & then they jumped right to the Gen. 3, they made changes to the Gen.3 & it puts the Cartridge higher into the Upper for a better feeding approach. I have a thread around here with measurements , because I had anearly CMMG Lower Build that would not function reliably with the org. LR PMag, but worked with all brands of Metal Mags & the Lancer L7's , then when they came out with the Gen. 3 PMag , it worked also. ( I had the same type malfunction , more often then every twenty rounds ) . The Mag will be marked as a Gen 3 , the original will not have that designation . The Mag Catch has helped others here & is also inexpensive to replace , but you have to make sure its a Armalite product ,AR 10 Catch , I think its a kit with the Spring & Mag release Button . Edited July 21, 2017 by survivalshop Quote Link to comment Share on other sites More sharing options...
Flabbergasted Posted July 21, 2017 Author Report Share Posted July 21, 2017 I think my gas tube is the proper length, at least it looks like it to me. I just looked at my magazines and they are Gen 3s. I'll be buying some different types of magazines next week and I'll try them out. Having more magazines is never a bad thing. The Armalite mag catch kit is out of stock on Armalite's site right now but I plan on buying it when it becomes available. It seems like the Armalite mag catch will be better than the one I have on there now. The mag release button is threaded on by a few threads. It seems like it is too short for the width of my gun. I'll start with those areas to see if that solves the issue. I'll most likely just replace the buffer spring while I'm at it since its cheap. I'll let you all know what the results are. Thanks! Quote Link to comment Share on other sites More sharing options...
survivalshop Posted July 21, 2017 Report Share Posted July 21, 2017 Looks OK . Just run her wet & maybe she will break in past this annoying issue . I know it drove me crazy sometimes , I can't stand it when things don't work right . Quote Link to comment Share on other sites More sharing options...
washguy Posted July 21, 2017 Report Share Posted July 21, 2017 Flabber If it doesn't lock back on last round you will still be having problems...locking back function chk is mandatory ....if it were me I would get a Tubbs spring or an orange Sprinco spring lets see a pic of your buffer up against a ruler...I think you said 2.5 so that should be a car 308 buffer.....you need a spring and maybe some more gas... get you a lancer mag too...that should take a flakey mag out of the equation Wash Quote Link to comment Share on other sites More sharing options...
survivalshop Posted July 21, 2017 Report Share Posted July 21, 2017 16 minutes ago, washguy said: If it doesn't lock back on last round you will still be having problems...locking back function chk is mandatory Yep , Quote Link to comment Share on other sites More sharing options...
Flabbergasted Posted July 22, 2017 Author Report Share Posted July 22, 2017 4 hours ago, washguy said: Flabber If it doesn't lock back on last round you will still be having problems...locking back function chk is mandatory ....if it were me I would get a Tubbs spring or an orange Sprinco spring lets see a pic of your buffer up against a ruler...I think you said 2.5 so that should be a car 308 buffer.....you need a spring and maybe some more gas... get you a lancer mag too...that should take a flakey mag out of the equation Wash Yes, the buffer is 2.5". Its the standard 308 car buffer. If I'm having trouble with the gun locking back after the last round wouldn't adding an extra strength buffer spring to the equation make if even harder for the BCG to lock back on the last round? Would just a standard buffer spring be better in this situation? Quote Link to comment Share on other sites More sharing options...
washguy Posted July 22, 2017 Report Share Posted July 22, 2017 26 minutes ago, Flabbergasted said: Yes, the buffer is 2.5". Its the standard 308 car buffer. If I'm having trouble with the gun locking back after the last round wouldn't adding an extra strength buffer spring to the equation make if even harder for the BCG to lock back on the last round? Would just a standard buffer spring be better in this situation? For now just get you a Tubbs flatwire car308 spring although the same spring is used in both rifle and car stocks...you cant go wrong.....get it at LaRue...cheaper and great swag on a small sale for them....The Sprinco orange spring with a heavy buffer is my new all time fav after last weeks testing of buffers and springs,but your'e right all my rifles have proper amounts of gas.....but you prolly have too little of a gas port.... you need to check the size of the port.....if you can get a dpms type car308 spring easy, and close to you get you one of those.... also do your mags rock back and forth in the magwell? Wash Quote Link to comment Share on other sites More sharing options...
98Z5V Posted July 22, 2017 Report Share Posted July 22, 2017 21 hours ago, survivalshop said: SS, YOU are a prime candidate for a genuine Armalite AR-10 gas tube. Big time, brother. WAY bad. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted July 22, 2017 Report Share Posted July 22, 2017 2 hours ago, washguy said: The Sprinco orange spring with a heavy buffer is my new all time fav Just so everybody knows, on that spring - and Sprinco makes GREAT springs... http://www.sprinco.com/tactical.html "ORANGE Spring" The ONLY specifically engineered EXTRA POWER Buffer Spring for .308 Carbine Platforms using standard 7" Depth M4 extension tubes and .308 short 2.5" buffers (Including aftermarket "heavy buffers.") You cannot clip coils from any other commercially available buffer spring to yield the proper spring loads for this application, especially in heavily gassed .308 carbine platforms. We started from scratch on this design to provide Operators with a viable alternative to existing OEM and aftermarket offerings. Platforms known to exist using this approach include DPMS, Bushmaster (Post 2010), Remington, CMMG, Mega, SA Defense, Colt 901, Rock River Arms and many others. Color Coded ORANGE. The Sprinco ORANGE spring is specifically designed for the .308AR system, specifically for DPMS-based LR308 recoil systems. That's the AR15 Carbine receiver extension (7" internal depth) and the 2.5" long .308AR Carbine buffer. Just don't want people with a rifle receiver extension going out and buying this spring, and saying it sucks. It doesn't suck. It excels - for exactly what it was designed to do. If you buy this spring, and use it on an Armalite AR-10 Carbine system, then just slap yourself. Or,I'll do it for you. Quote Link to comment Share on other sites More sharing options...
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