6132expert Posted August 13, 2011 Report Share Posted August 13, 2011 OK, 2 day shipping on my ammo. I was extreamly excited when I got hom and it was on the front porch. So I loaded 3 rounds asap I am not cycleing. I know my BCG is not coming back enough. I fired the first and it ejected about 4 o clock and did not cycle. Fired the second same thing. Then I fired the 3rd and the bolt slammed aginst the empty case before it was ejected and no bolt lock on the last round.Do I need a different spring?What are you useing?Or am I going the wrong direction? Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 13, 2011 Report Share Posted August 13, 2011 List the setup on the rifle, please? Or link to it?Disregard - got it:http://308ar.com/forum/300-aac-blackout/offical-300-blk-thread/What we have is, is aAAS Lower / Multi CalRRA single stage trigger LPKOver sized selectorBrownells lazer etched upperBrownells ( dont tread on me ) dust coverBrownells lazer etched ( American Flag ) take down pin and mag releaseTear drop forward assistMagpul Moe, Moe grip, Winter trigger guard, XTM panels,AFG2, and Mbus Gen 2 sightsRRA BCG and CHYHM quad rail With end capCMMG 16 inch carbine lenghtCMMG single rail gas blockunknown muzzle break Quote Link to comment Share on other sites More sharing options...
Jgun Posted August 13, 2011 Report Share Posted August 13, 2011 some questions for you, When you manually cycle the action, does the bolt carrier go back far enough to lock on the bolt catch? If so what spring and buffer do you have, also what ammo are you using, the 220 subsonic? In your opinion is it short stroking (traveling far enough back to eject the empty case but not far enough to clear the back of the mag and strip and load a new rd? Quote Link to comment Share on other sites More sharing options...
6132expert Posted August 13, 2011 Author Report Share Posted August 13, 2011 some questions for you, When you manually cycle the action, does the bolt carrier go back far enough to lock on the bolt catch? If so what spring and buffer do you have, also what ammo are you using, the 220 subsonic? In your opinion is it short stroking (traveling far enough back to eject the empty case but not far enough to clear the back of the mag and strip and load a new rd?OK, I can manually pull the BCG back and it locks with no issues. I am using I assume a standard carbine spring and buffer that comes wih the Magpul kits from Pk firearms. I am using the 220 subsonic ammo and yes it is short stroking for sure. The BCG is coming back just enough to eject the brass but not load a new round. Quote Link to comment Share on other sites More sharing options...
Jgun Posted August 13, 2011 Report Share Posted August 13, 2011 I have not personally used the 220 subsonic , or any other factory ammunition yet. So understand that I'm just throwing out ideas. I think I read a thread somewhere (300 BLK forum?) where they were discussing that the 220 subsonic performed better in a suppressed application where the extra back pressure aided cycling. I think that the discussion was about someone that had a problem similar to what your describing, but I thought they had a SBR. If it were me I'd give AAC another call and ask them if your problem might be ammunition related. If, in fact your problem is due to not enough gas impulse, I would think your options are, different ammo, open up the gas port to get more gas to cycle with the present ammo, run a suppressor, or see if you can get a lighter buffer and/or buffer spring. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 13, 2011 Report Share Posted August 13, 2011 CMMG says the 16" carbine gas barrel is "Acceptable" shooting subs unsuppressed, but that barrel might not like the subs you're shooting. It's supposed to work, but it might not with your particular ammo. <dontknow> Quote Link to comment Share on other sites More sharing options...
6132expert Posted August 13, 2011 Author Report Share Posted August 13, 2011 I like the suppresor idea for sure. Maybe somewhere in the future when I get a job that can come into play. For now I am going to go back and check the gas block to makesure it is alined just right and and fire a few more rounds. I can say this, when I manually lock the bolt back I can tell the spring is very stiff. Much more stiff then my factory built RRA 556. Hey there is a spring and buffer for me to try out. <thumbsup>I will get it figured out , I hope anyways. If all fails then I may be puting in an order with AAC for the new 125 grain match ammo, or the new hunting ammo they are fixin to start taking orders for. Heck Cor-bon has ammo also.Well the lss stiff spring did not do anything for it and the gas block is right on form what I can tell. I may just have to hold out and get some different ammo to try. This is my first complete build, so I will just have to trouble shoot and learn. Quote Link to comment Share on other sites More sharing options...
6132expert Posted August 13, 2011 Author Report Share Posted August 13, 2011 Ok, guys I got it cycling great and the BCG is locking back. I figured if I break it I can fix it. So what I done was I pulled the spring and buffer I removed 1 weight from the buffer , but later added it back. I started cutting spring coils 1 by 1 untill I got to number 12 on number 12 is when the BCG stripped and loaded another round, but the BCG did not go forward completely ( this is when I put the weigh back in the buffer ). I loaded 3 rds. and my rifle functioned perfictly. Now I have a question. I am shooting the 220gr. right now with the shorter spring now installed what is going to happen when I shoot the 123 or the new 125 gr match ammo?I looked for a less stiff spring , but had no luck finding one. If anyone knows where to find one let me know or post a link for future referance. Quote Link to comment Share on other sites More sharing options...
imschur Posted August 13, 2011 Report Share Posted August 13, 2011 maybe once the weapon breaks in you can go back to a spec spring. I wonder if a Superior Flat Wire would help. Quote Link to comment Share on other sites More sharing options...
6132expert Posted August 13, 2011 Author Report Share Posted August 13, 2011 I looked at those , but I dont know if this flate wire spring will fix my problem. What does everyone think about this? Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted August 13, 2011 Report Share Posted August 13, 2011 A stiffer spring is more likely to drive your bolt all the way forward when you're using the carrier weight (or when you're not for that matter), which is probably why Drew recommended it. The flat wire spring recommended has been known to solve the same problem for other users in other forums. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 14, 2011 Report Share Posted August 14, 2011 The 16" carbine gas setup is the preferred all around config, it's just not great with subs, unsuppressed. I'm thinking the ammo is the whole problem here, and it would cycle fine in it's original config, with different ammo. <dontknow> Quote Link to comment Share on other sites More sharing options...
survivalshop Posted August 14, 2011 Report Share Posted August 14, 2011 Could be ammo , some rifles just don't like sub sonic ammo . What's the round count ?New build ? As said ,may give problems until you get some round count.How well lubed is the action ?You made a custom spring for that set up & it may work fine with super sonics , only way to know is to put some of it to work in your rifle.Make sure your gas block is correct, some are set back the thickness of the front hand guard guard cap.Using AR 15/16 buffer & spring ? Not 308 parts . Quote Link to comment Share on other sites More sharing options...
6132expert Posted August 14, 2011 Author Report Share Posted August 14, 2011 Could be ammo , some rifles just don't like sub sonic ammo . What's the round count ?New build ? As said ,may give problems until you get some round count.How well lubed is the action ?You made a custom spring for that set up & it may work fine with super sonics , only way to know is to put some of it to work in your rifle.Make sure your gas block is correct, some are set back the thickness of the front hand guard guard cap.Using AR 15/16 buffer & spring ? Not 308 parts .Yes this is a new build and as of now the round count is at 40. I lubed it up with a quart of yama lube( not the whole quart of course. The gas block is fine it was fit by CMMG with the barrel. The spring/buffer is AR 15 not 308. I am going to call Monday and get my order in with AAC for some 125 gr match ammo and order a new spring.I am really wanting to know if my rifle with the modded spring can fire the supersonic ammo with no issues. If it can is the shortened spring going to cause any damage in the long run? Quote Link to comment Share on other sites More sharing options...
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