This is what I did to troubleshoot my 7.5" SBR malfunctions.
- Bought a new Gas Key & re-staked it properly.
- Bought a heavier buffer (H2).
As for now, it runs like a champ. I've done around 500 round without no malfunctions.
I hope this helps.
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This is what I did to troubleshoot my 7.5" SBR malfunctions.
- Bought a new Gas Key & re-staked it properly.
- Bought a heavier buffer (H2).
As for now, it runs like a champ. I've done around 500 round without no malfunctions.
I hope this helps.
- Eric
Owner/Instructor at Semper Paratus Arms
Facebook: https://www.facebook.com/SemperParatusArms/
Semper Paratus Arms AR15 Armorer Course http://www.semperparatusarms.com/cou...-registration/
M4C Misc. Training and Course Announcements- http://www.m4carbine.net/forumdisplay.php?f=141
Master Armorer/R&D at SIONICS Weapon Systems- http://sionicsweaponsystems.com
Since no one has mentioned this. Have you tried different magazines encase you are having a magazine feed issue.
"You done good. Remember the rules of home gun smithing: Measure it with a micrometer, mark it with chalk, cut it with a torch/dremel, grind it to fit, paint it to match with a sharpie!"
Yes, I used several different pmags and a USGI aluminum mag.
I tested it again yesterday with .223, and it malfunctioned the same as before. It passed the short stroke test as well...when it functioned properly.
Oh well. Maybe I can turn it into a blowgun or something.
OK. A little recap. As I understand it, your SBR works with .223 and some 5.56?
Odd. In any case something has occurred to me. Contact M&A and ask them what size their gas port is. Also, I think I would remove the rail and check the gas block. I have no idea if it's pinned or screwed, but still check it. I would also try and see about replacing the gas tube.
You may also want to put it back into it's original configuration. I personally think that a 7.5" is a waste of money so I wouldn't want to sink alot into it.
Owner/Instructor at Semper Paratus Arms
Facebook: https://www.facebook.com/SemperParatusArms/
Semper Paratus Arms AR15 Armorer Course http://www.semperparatusarms.com/cou...-registration/
M4C Misc. Training and Course Announcements- http://www.m4carbine.net/forumdisplay.php?f=141
Master Armorer/R&D at SIONICS Weapon Systems- http://sionicsweaponsystems.com
I'll be sure and do that. Since I found that .223 malfs as well as 5.56mm now, I'm leaning back toward the A5 being the culprit.
I'll try it again with the standard Milspec RE and carbine and H2 buffs installed for one last try before I sell it off. I'm definitely not going to pour any more cash into this thing. I'm just trying to make what I have work. I bought it before I knew better, sadly.
Fortunately, my AR knowledge has increased a great deal in the last few years. I'm currently waiting on my first KAC upper. I have an IWS lower now, and it's incredible. I suppose in a way, experiences like this with lower grade components make me appreciate the BCM/DD/Colt/KAC guns more.
Thanks for the help!
Have you tried upgrading the extractor spring?
Something I should have asked before. Do you by chance have an O-ring on your extractor spring assembly? If so, remove it.
Owner/Instructor at Semper Paratus Arms
Facebook: https://www.facebook.com/SemperParatusArms/
Semper Paratus Arms AR15 Armorer Course http://www.semperparatusarms.com/cou...-registration/
M4C Misc. Training and Course Announcements- http://www.m4carbine.net/forumdisplay.php?f=141
Master Armorer/R&D at SIONICS Weapon Systems- http://sionicsweaponsystems.com
I am no expert, but it looks like the "cuts on the barrel" are the M4 feed ramps rather than a standard barrel.....if I am wrong, someone please explain/show me the difference (on an installed barrel, hard to tell when installed...IMO).
Last edited by hotrodder636; 08-12-11 at 18:42.
Problems started after the install of a VLTOR Emod A5 combo kit?
Standard A5 buffer is 5.3oz.
I built a very picky AR 7.5" pistol w/stainless heavy contour barrel that did the same thing yours seems to be doing.
I changed the buffer to an H2 w/same carbine action spring and I opened gas port up to .076 from .061 to start cycling properly.
After that I dropped an adjustable gas block on it to adjust to ammo changes, found the sweet spot and left it there.
I'm not saying you will need to do all that but start at the buffer weight.
First change to lighter buffer and see if that will get your timing back. H or H2.
Good luck.
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