Results 1 to 10 of 14
-
June 6th, 2020, 10:27 AM #1Super Member
- Join Date
- Oct 2007
- Location
-
Phoenixville,
Pennsylvania
(Chester County) - Posts
- 565
- Rep Power
- 21474853
AR pistol converted to 300 Blackout - Won't cycle subsonic
Replaced the 8" barrel on my .223 AR pistol with an 8.5" .300 blackout barrel. Shoots and cycles supersonic ammo fine, but will not cycle with subsonic ammo. It ejects the spent casing but will not pick up the new cartridge, running with either a flash hider or a Sig suppressor. I thought the increased backpressure from the suppressor would help but no. Acts the same with different magazines. Any suggestions on where to look?
-
June 6th, 2020, 12:50 PM #2Super Member
- Join Date
- Oct 2012
- Location
-
Jim Thorpe,
Pennsylvania
(Carbon County) - Posts
- 675
- Rep Power
- 2079673
Re: AR pistol converted to 300 Blackout - Won't cycle subsonic
Check the length of the gas tube-may need shorter. Check the alignment of the gas port to the gas block to the gas tube.
-
June 8th, 2020, 12:39 PM #3Super Member
- Join Date
- Oct 2007
- Location
-
Phoenixville,
Pennsylvania
(Chester County) - Posts
- 565
- Rep Power
- 21474853
Re: AR pistol converted to 300 Blackout - Won't cycle subsonic
Checked all of the above which seem good. I put in a friend's lightweight bolt in the pistol and subsonic ammo cycled correctly. Although the bolt still doesn't lock back. Before I spend the money on a new bolt, any other thoughts on what to do? Thanks!
-
June 8th, 2020, 05:03 PM #4Grand Member
- Join Date
- Aug 2008
- Location
-
DeepInTheWoods,
Pennsylvania
(Warren County) - Posts
- 2,418
- Rep Power
- 21474854
Re: AR pistol converted to 300 Blackout - Won't cycle subsonic
NOT a AR15 Guru, me. But I had a similar issue.
My Ar pistol was working and then it quit cycling reliably.
Somebody had fitted an aluminum combination gas block and Picatinny rail to it. The gas ate away the aluminum and gas was escaping.
Not enough was getting back to the Bolt to TCOB.
Subsonic rounds are producing less gas , YES?
Look to an adjustable gas block ?American by BIRTH, Infidel by CHOICE
-
June 8th, 2020, 05:40 PM #5Grand Member
- Join Date
- Jan 2016
- Location
-
Pittsburgh,
Pennsylvania
(Allegheny County) - Posts
- 1,650
- Rep Power
- 21474846
Re: AR pistol converted to 300 Blackout - Won't cycle subsonic
How subsonic are your loads ? You may have to bump up your charges or use a different powder or bullet combo. Have you chrono'd them ?
-
June 8th, 2020, 05:56 PM #6Grand Member
- Join Date
- Jan 2013
- Location
-
Richboro,
Pennsylvania
(Bucks County) - Posts
- 3,053
- Rep Power
- 21474851
Re: AR pistol converted to 300 Blackout - Won't cycle subsonic
You might want to consider a reduced power buffer spring for subsonic. It doesn't sound like your bolt is fully retracting.
-
June 8th, 2020, 07:17 PM #7Grand Member
- Join Date
- Aug 2011
- Location
-
Moscow,
Pennsylvania
(Lackawanna County) - Posts
- 4,026
- Rep Power
- 21474853
Re: AR pistol converted to 300 Blackout - Won't cycle subsonic
Subsonic routinely doesn’t cycle in these platforms without a suppressor. Which is what the subs are designed for
-
June 9th, 2020, 08:34 PM #8Member
- Join Date
- Feb 2014
- Location
-
Landenberg,
Pennsylvania
(Chester County) - Posts
- 40
- Rep Power
- 0
Re: AR pistol converted to 300 Blackout - Won't cycle subsonic
My 2 cents, your buffer spring or buffer weight is too high. Do you know what buffer you have? I just replaced my buffer and spring with a captured recoil spring and buffer to help cycle subs out of a 300blkout conversion.
-
June 10th, 2020, 09:08 AM #9Super Member
- Join Date
- Oct 2007
- Location
-
Phoenixville,
Pennsylvania
(Chester County) - Posts
- 565
- Rep Power
- 21474853
-
June 10th, 2020, 11:03 AM #10
Re: AR pistol converted to 300 Blackout - Won't cycle subsonic
Do you roll your own subsonics?
Once I got over the coolness I completely quit shooting subsonics. It's just my unsolicited opinion, but aside from the fun factor they don't serve me any self-defense purpose.
*Since I quit shooting them I'm rusty on my recollection, but I think I may have run into the same problem using one powder until I was able to find A1680."It seems that the Constitution is more or less guidelines than actual rules"
My feedback: http://forum.pafoa.org/showthread.php?t=305685
Similar Threads
-
99% SOLVED: 8" 300 Blackout won't eject/cycle
By esh21167 in forum RiflesReplies: 67Last Post: July 11th, 2016, 01:00 PM -
Subsonic 300 Blackout Loading
By Clark Kent in forum Ammunition & ReloadingReplies: 20Last Post: July 10th, 2013, 11:13 AM -
Subsonic .22 in pistol or rifle?
By bluto in forum PistolsReplies: 18Last Post: April 27th, 2011, 05:30 AM
Bookmarks