my DPMS 308 reliability-can it be improved?

[Okie03]

Had about same type of problems with my CMMG 308, Slash's buffer and spring, is the only way to go. I also changed ejector and extractor springs while I was at it. Reliability went from less that 50% to 100% function. 0 failures to feed, fire, eject and chamber since changes, have shot around 300 rounds since then, mix of various ammo. Gun would not work before that with anything reliably. Good luck.

[SMC527]

This is my planned route. After the deer hunting trip, replace the adjustable gas block and add a slash buffer and spring.

I am still concerned that will to fox the issue 100% as the FTEx were very, very bad (considering the tool marks and ripped off rims).

As I said, it is a shooter, though......and if I can keep its outstanding accuracy and increase its reliability, I am willing to invest a few hundred dollars to head down that path.

[Okie03]

Hope you get it fixed, I tried an extra power buffer spring (308) and found it helped quite a bit, then went with the Slash buffer and spring-good to go after that, I have tried the tungsten powder buffers, I didn't like them as well as solid weights. If you want to try polishing chamber, a fairly safe way is to use a chamber mop, not brush and very fine valve grinding compound, Brownells (JB) bore compund or rubbing compound and electric drill. The rubbing compound is almost foolproof as to doing any damage, it won't remove metal,it just lightly polishs the chamber. Downside is you will have a mess and will need to do a lot of cleaning, won't hurt the bore to push it on through, will get in rifling, so needs scrubbed really good. Using various grits of "sandpaper" works to remove the tool marks but is not something for the faint of heart. I am sure others have different and/or better methods, but this has worked for me . This won't remove any machining marks, but it will help smooth them out.

[Dr69er]

If your seeing tool marks on your brass cases, that's part of your
problem, and it's partially causing FTE problems...Also, make sure
you have the correct buffer and buffer spring combos...If your
brass case heads are being torn, that is a symptom of over-
gassing and pre-mature bolt unlocking...Also, check your
extractor and extractor spring for any damage etc.

All of the above Issues will have to be addressed seperately:

For the rough chamber, take one of your un-primed virgin brass cases,
use a long sheet metal screw incerted through your primer pocket/flash hole
of your brass case (cut the screw head off) add some liberal amounts
flitz polishing compound to your brass case exterior and place it
Into your electric drill and start polishing.

Use a heavy buffer and wolff xp buffer spring to help slow down
your bcg velocity...the "slash" buffers are pretty good...this will
help with the overgassing Issue.

The correct gas port diameter should be in the range of .088"-.092"
for the rifle length gas system. don't forget it's a 3:1 ratio
for gas port diameter Increase to gas volume/pressure.
.308 AR barrels tend to be overgassed from the factory.

As for adjustable gas blocks, I would stick with the PRI or better yet
Syrac. Don't forget adjustable gas blocks can be a double edged sword...
The rifle should be able to run 100% without a adjustable
gas block.

Finally, check your extractor and spring, check for burrs or defects...
polish It or replace It if neccessary.

Good Luck.

[1911nbmore]

My Bushmaster .308 ORC was perfect for the first 300 rounds. After that it was nothing but grief once I attach the can. The last thing I wanted to do was send it back to Bushmaster because it was pretty accurate with my handloads sub MOA if I did my part. I ordered the Syrac adjustable gas block from Brownell’s. Installed it today and took it to the range, boom problem solved. It was so over gassed it would run just on click from gas being completely closed off. I'm glad I finally got this sorted out.

[carbinero]

...
The rifle should be able to run 100% without a adjustable
gas block.

Oh man, this is the money quote.

[signkutter]

My Bushmaster .308 ORC was perfect for the first 300 rounds. After that it was nothing but grief once I attach the can. The last thing I wanted to do was send it back to Bushmaster because it was pretty accurate with my handloads sub MOA if I did my part. I ordered the Syrac adjustable gas block from Brownell’s. Installed it today and took it to the range, boom problem solved. It was so over gassed it would run just on click from gas being completely closed off. I'm glad I finally got this sorted out.

The Syrac block is awesome and it wont go out of adjustment on you. Highly reccomend

[Benito]

Sort of a necro-post here, but I'd rather not create new threads for no good reason.

Are Sprinco's dual extractor springs compatible with DPMS LR-308 bolts/extractors? I am considering trying one, but wanted to check if the combination is good to go. Any insight is greatly appreciated

[rootbrain]

Bump for answer to last question.

Need to know.

Rootbrain

[Bushytale]

The Sprinco double extractor spring set is correct for the DPMS .308 but is not as strong as the original Bushmaster/DPMS double spring set. The Fulton Armory spring and insert seems to be slightly stiffer.
I have a BM .308 ORC which is essentially a DPMS 16 inch, but with a better barrel. It came with a std. commercial carbine receiver extension and the short buffer which is 2.5 inches long and weighs 3.8 oz. I replaced that with the Vltor 10A5SR receiver extension which is .750 longer than a carbine ext. and a regular carbine H3 buffer which is 3.25 inches long and weighs 5.4 oz. With the longer extension (same length as Armalite carbine) you can then use the Armalite carbine recoil spring and it all works together like it should. I sourced those parts from DSG Arms. With that set-up you can adjust buffer weight if needed with std. carbine buffers H H2 etc.
The Vltor rec. ext. is mil spec dia. I wanted to go to the mil spec tube anyway and use a Magpul ACS-L stock.
You can get to the same basic place with a Slash buffer and spring and not have to change the ext. and the stock.

Hope this information helps.