|
Post by dirwood on Apr 9, 2017 17:03:21 GMT -8
Have recently put together a 25-45 AR and having some troubles with it cycling properly. Barrel is a Blackhole 20" rifle length set up with A2 stock, PSA boron bolt and it will not cycle the action correctly, sometimes it will not fully extract the fire case, other times it will eject a case but not pick up a new one. I have tried a different bolt with the same issues and have used the PSA bolt in another rifle with out issue. I am relatively new to the AR platform and not sure what to do next? The barrel is extremely accurate and would really like to get it to function correctly. I have gone as high as 28grs of H335 with a 90r gameking and it still won't function correctly. I have verified the gas tube and gas port is clear and alignment looks correct, thinking maybe a different buffer spring or possibly a larger gas port?
Thanks for any advice or tips
|
|
|
Post by GLSHOOTER on Apr 9, 2017 18:43:54 GMT -8
Have you tried a different lower? Adjustable or regular gas block?
Greg
|
|
|
Post by dirwood on Apr 10, 2017 2:35:26 GMT -8
I have not tried a different lower yet, i hope to get a chance to do so today. Rifle does have an adjustable gas block and i removed it to verify it was adjusted for wide open gas, also plugged the chamber with a fired case and blew compressed air into muzzle end of barrel and felt it it flowing out of gas tube to verify good flow through the gas system. Are there any issues with the 25-45 and rifle length gas systems? Perhaps a slower powder than H335 would great a different gas impulse?
Thanks,
|
|
|
Post by wfa on Apr 10, 2017 6:20:08 GMT -8
A2 stock? Are you using a "rifle" buffer (which is heavier than the M4 buffer)?
|
|
|
Post by dirwood on Apr 10, 2017 7:40:58 GMT -8
Yes, i am using full sized fixed stock (Magpul PRS), with A2 rifle buffer and spring. I received an email from Sharps after making an inquiry with them about my issue and they said they use H2 buffers with their rifle length gas setups. Not sure what it take to switch over to a H2 set up, just a buffer or would i need new spring and spacers as well? Forgive my lack of knowledge but still learning about the various AR setups.
|
|
|
Post by GLSHOOTER on Apr 10, 2017 12:44:29 GMT -8
It's just a straight buffer swap normally. The H2 is lighter than a standard buffer. The trouble is an H2 buffer is for a CARBINE stock. I've never heard of anyone running one in a full rifle length stock on purpose. What does the carbon ring under the GB look like?
Try a new lower first.
Greg
|
|
|
Post by dirwood on Apr 13, 2017 17:07:56 GMT -8
Greg,
I will be trying another lower this weekend and see if the problem follows the lower or the upper. As for the carbon ring under the gas block, what exactly should i be seeing?
Thanks,
JW
|
|
|
Post by GLSHOOTER on Apr 13, 2017 17:34:45 GMT -8
|
|
|
Post by dirwood on Apr 18, 2017 17:25:29 GMT -8
I tried two different lowers, one another A2 length and the other a carbine length stock. Functioning was just same, still not fully extracting fired case or when it does extract a fired case it will not pick up a new case. I checked the gas block alignment and it was spot on, checked the gas tube for blockage, check tube to gas key fit and it was fine. Opened up the gas port by .010" and now it will reliably extract fired cases but still not picking up new round or locking back on empty magazine. I ordered up a reduced power buffer spring from Wolff to try but am running out of options to try.
|
|
|
Post by GLSHOOTER on Apr 18, 2017 18:24:36 GMT -8
How big is your port now?
Greg
|
|
|
Post by peabody on Apr 19, 2017 16:52:15 GMT -8
What brand and size of mags are you using? A tight mag spring can create excess friction on the bottom of the bolt carrier, which can suck up energy from the moving bolt assy. I've experienced that with some poorly-modded 10/30 mags that compressed a 30 round spring into a 10 round space - when empty. Not a good design. Another cause can be friction within the buffer and tube, which lube can fix. And then there's the buffer and spring weights. But those have already been noted...
|
|
|
Post by dirwood on Apr 23, 2017 8:46:07 GMT -8
How big is your port now? Greg Greg, Gas port size is .109 now, up from .0995. Just got done putting a new reduced strength buffer spring from Wolffe and loading a few more loads to try this afternoon.
|
|
|
Post by dirwood on Apr 23, 2017 8:47:14 GMT -8
What brand and size of mags are you using? A tight mag spring can create excess friction on the bottom of the bolt carrier, which can suck up energy from the moving bolt assy. I've experienced that with some poorly-modded 10/30 mags that compressed a 30 round spring into a 10 round space - when empty. Not a good design. Another cause can be friction within the buffer and tube, which lube can fix. And then there's the buffer and spring weights. But those have already been noted... Been using mostly 20rd P-mags along with a 5 round Stoner, all with same effect.
|
|
|
Post by GLSHOOTER on Apr 23, 2017 15:02:21 GMT -8
How big is your port now? Greg Greg, Gas port size is .109 now, up from .0995. Just got done putting a new reduced strength buffer spring from Wolffe and loading a few more loads to try this afternoon. That ought to be plenty for that cartridge. Greg
|
|
|
Post by peabody on Apr 23, 2017 19:50:02 GMT -8
Question for Greg - Wasn't there recently a thread involving cycling issues that were caused by rough edges in the bolt and/or barrel extension lugs? I recall something along that line that was corrected with a little smoothing of the lug edges/surfaces...
|
|