Unmodified DPMS carbine 5.56 with 6 position stock. Ever since new, it would not lock back on the last round. Have shot a couple hundred rounds of various ammo and several different mags. Just picked up some Wolf(since it’s supposed to weak) and it locks back nearly evey time. Never had any failures other than not locking back on the last round. Gun is clean and wet. So it seems the gun is overgassed and from what I’ve read that’s common. I also checked the buffer and it has the 3 regular weights with no Tungston ones.
So I was planning on trying the H2 or 3 buffer, but I have also read that a new barrel is the correct fix to get the correct gas hole size.
So my main question is, can the front sights gas hole be modified by maybe welding it up and redrilling it or is the main hole sized by the barrel only? Or is overgassed just as fixable with the heavier buffer?
Pass on re-drilling the gas port. Just get an H2 or H3 buffer and a SpringCo blue buffer spring.
C4
Agreed. Dumping any more effort into that barrel is a waste. Just shoot the piss out of it and start saving for your next (BETTER) upper/barrel.
Ok, I installed a H3 buffer and it locks back a lot more than it did using a variety of ammo. I looked for the Sprinco spring on their web site and only saw pistol springs. I think a stiffer spring should get me fixed up. I noticed two things while shooting today. 1) If I stood up and held the rifle tight to my shoulder, it seemed to lock back even better. 2) If I held light pressure on the bottom of the bolt catch, like I read in a thread, it locks back every time. From all the searching I’ve done, it looks like my bolt catch is fine and is not sticky at all.Does anyone have a link to stiffer springs? The ones I find just say carbine spring, and nothing about being stiffer. Also, just want to mention, the wolf ammo locks back every time like it did before thre H3 buffer.
Thanks
“overgassed” sounds under to me. What size is the gas port now?
Read it again Tweak.
It is only locking back on the WEAKEST ammo.
I, also, am a fan of the blue spring and use one in my 14.5" middy.
http://www.sprinco.com/tactical.html
or you could order it from here and get fast shipping and great CS. 
The added spring pressure will keep the Bolt in battery longer and should give it time to have chamber pressure subside.
Also, maybe consider one of these kits:
Even if you have a donut and black insert already…it’s worth it just for the superior quality BCM CS extractor spring. A full swap out would also help further diagnose the issue (and work toward a fix). Good luck, brother and keep us in the loop.
lots of other factors at play here HM
I agree. He could have the wrong spring in his bolt catch too.
My general recommendation is to use good ammo whenver trying to isolate a problem or doing any troubleshooting. Wolf does not fall into that category.
Get some M855, M193 or similar and see how it works. What magazines are you using and what condition are they in?
My mags are all like new. I have the two 30rd DPMS ones that came with the gun and one 30rd one that I bought at a local store, looks like one used by military. Can’t remember what make it is, but it has the green follower. All the mags seem to function the same. I load 1 round in each and cycle through them. I am using Federal xm855 green tip, Remington .223 45gr jhp, Wolf .223 55gr, and Winchester 5.56 55gr. I bought the Wolf because I read it is supposed to be a weaker round. My thinking was, if it locks back with weaker ammo, I have a over gassed condition. The heavier buffer definently helped. I ordered a heavier buffer spring and extractor spring kit today, so I should know where I stand shortly. I have never had a failure to extract or feed.
I have had this problem from the day I bought the gun. I called DPMS and they said to send them the lower reciever, but I never did. I figured I could fix it myself.
I think at this point I would stop chasing ghosts and have someone look at that knows more about it.
No ghosts here. I know what is wrong with it, I can duplicate the problem all day long. Just getting advise on the best way to fix it. Barrel VS buffer as in my first post(maybe my title sucks). I have seen the adjustable gas blocks and just thought, can I resize a front sight style block to the correct diameter. I am going the buffer route and installed the H3, which made a very noticeable difference in a good way. Had I got the stiffer spring too, the problem would most likely be gone. Had a little trouble finding the correct spring and now, with a little link help, have ordered the spring too.
Thanks for the help.
I think you have it nailed down, but just for some more evidence…
Do you have a full auto carrier?
What is the ejection pattern for the M193 and the Wolf?
No, not full auto. That would be cool though.
All the brass cased ammo lands around 1- 2:30 o’clock. Some even stayed on the table landing about 4 feet away. All the Wolf lands in one consistant area around 4 o’clock. Looks like the higher power stuff is bouncing off the forward assit(puts a dent in the cases). I am not a Wolf hater and will use it. If the gun starts short strokin on Wolf and not other ammo when I get my stiffer spring, I will just swap buffers and springs when I do use it.
He meant a full auto carrier, not a full auto lower.
Sorry, I really dont know. Its just a 800 dollar off the shelf rifle. I would think not auto though. May be worth a shot to try one. Ill just have to see how the new buffer spring does first
pull the carrier out, flip it over…what’s it look like? The “AR-15” or the “M-16” (full auto) carrier? My bet is AR15 with the DPMS
I did not see this tried yet, try unloading a mag, put it in the magwell all the way and cycle the action a.k.a. Pull the charging handle and see if the bolt locks back that way it may be as simple as a bad follower. If that is the problem try the magpul followers they work great. Heck you might want try that anyway it might solve the problem
Definently have AR15 carrier. Locks back fine by hand and with Wolf ammo. I have a spring on the way, so I’ll try it first. I can order the auto carrier too if I need to. I see it’s heavier. I am also courious to see what my gas port size is, so I’ll check it. I read on AR15Barrels web site that they can resize a port that is too large.