DPMS308 FEEDING PROBLEMS

[Cabinetman]

Hi all.  This is my first post at this forum so please be kind!  LOL

I've got a DPMS LR308B and have been shooting only 7.62 x 51 surplus through it exclusively.  The chamber was cut for .308 Win but I, too, bought this rifle to burn up my surplus which I've collected for quite a while.  I've run Dag, Port, and Hirt through it without a hitch.  I have found that the BCG likes to be lubed well but have only used Militec 1 in ALL of my rifles, both commercial and military and have been extremely pleased with the results.  Even my old Garand loves the stuff and it's a lot cleaner than greasing the snot out of it.  The parts clean up easier, too. 

Regarding Mags I've got both the DPMS mags supplied with the rifle as well as four C-Product Mags.  All six of the mags have worked fine.  I do find that sometimes the first round is difficult to strip from when loaded to the full 19 round capacity.  I'm experimenting with adjusting just slightly the rear of the mag lips so that the bolt have a bit more to catch on the way home.  If, howeve,r I only load 15 rounds in them they work perfectly. 

I've also found that the chamber in this rifle like to be clean.  I believe that's because It's tighter than a traditional military rifle chamber and that's probably why it will sometimes leave an expended brass in there although that only happened once when the rifle was brand new. 

Glad to have found this site.  I surely love this zombie killer of a rifle.  Easily this rifle can perform out to 400 yards.

Rome

[98Z5V]

Rome, it is very, very good to have you here - welcome aboard, man!  <thumbsup>

[Cabinetman]

Thanks. I've been around for a while on Parallax and Gunboards as well as the AR15 forums.  I've been drawn to the 'AR-10' type platform for a while and there isn't a lot of info out there about it.  I hope that this forum will continue to stay active in this arena.  My DPMS LR308b rifle is now my "go-to" rifle for a lot of reasons.   

Rome

[Carbon.shooter]

first and foremost thanks everyone for writing about what problems they have had and what or how they fixed them...  i have a DPMS and magpul PSR stock.  i also had jamming/ feeding problems... 

when i was trouble shooting what i found was that with the fixed buffer tube and rifle buffer that the bolt could not cycle far enough back to properly eject... (the bolt was still about 1/2 inch from being behind end of bullet to feed next)

I ended up shortening the rifle buffer and now absolutely no feeding or cycle problems at all...

now for my question.. what would happen if I use the buffer from the collapable stock in my fixed buffer tube..I know they are shorter... would it cycle and work ok??  I was thinking of getting one of the Hydraulic Recoil Buffer but would hate to spend the $$ and have to modify it or go back to the first feeding problem.. thank you for any and all input

[98Z5V]

You're using an AR-15 rifle buffer.  You need to be using a .308 AR-specific rifle buffer (and .308-specific spring).  <thumbsup>

This was the give-away:

...what i found was that with the fixed buffer tube and rifle buffer that the bolt could not cycle far enough back to properly eject... (the bolt was still about 1/2 inch from being behind end of bullet to feed next)

[onebigelf]

Obviously this is a great thread for first posts!.  I recently picked up one of these rifles to replace an FN-FAL as my primary rifle.  Love the FAL, but it just doesn't have the accuracy the DPMS does.  The LR-308 is nearly on par with my 700 Tactical.  I had a similar feeding problem with my factory mags, but I'd also ordered a dozen Pmags.  When they came in I tried it again and had zero problems.  I also use Mobil 1 as my gun lube and have for many years.  In fact, I'm still working from the original gallon jug!

John

[Carbon.shooter]

thank you!!  <thumbsup>

I wondered that but everything seems to work so good..  except for the length..

I had ordered it from dpms after using search 308 buffer tube..

this is what had come up

Buttstock Extension Tube

Model: BS-09

Sale Price: $19.95

where would you suggest I get the correct tube and spring from?

again.. i appreciate your help!!

[98Z5V]

It's not the tube, brother.  That (receiver extension, buffer tube, etc.) is the same for the 15 and the .308.  It's the actual buffer.  The AR-15 rifle buffer is 5.900" long, and the .308 AR rifle buffer is 5.200" long.  that 0.700" difference in buffer length is the 1/2" (approx.) that was screwing you.

The spring rates and lengths of the 15 vs. .308 buffer springs are different, too.  Don't run an AR-15 rifle spring in a .308.  It's nowhere near strong enough to handle the .308 Win loads.

[YWHIC]

Tada,

DPMS 308 Carbine Buffer is $20 can be used in AR 15 collpasible stocks..

http://www.rainierarms.com/?page=shop/detail&product_id=2638

DPMS 308 Rifle A2 stock buffer is $19  and used for FIXED stocks that would use the A2 type tube.. *works with MagPul PRS stock as noted under the reviews on the MidWay site..

http://www.midwayusa.com/viewProduct/?productNumber=913498

Midway has the 308 spring and tubes also..

http://www.midwayusa.com/viewProduct/?productNumber=797669&cm_vc=U016

http://www.midwayusa.com/viewProduct/?productNumber=489724&cm_vc=U016    (again they say its for the PRS stock in the reviews).

been down this road before.. these were in my favorites..  Lol

Al

[98Z5V]

DPMS 308 Rifle A2 stock buffer is $19  and used for FIXED stocks that would use the A2 type tube.. *works with MagPul PRS stock as noted under the reviews on the MidWay site..

http://www.midwayusa.com/viewProduct/?productNumber=913498

Just a bit of info for everyone else - there is no such animal as an "A2 receiver extension" - buffer tube, whatever the names are that come up.  Real name is "Receiver Extension." 

There is only an AR-15 Receiver Extension, when talking about the rifle-length tubes.  It's the original, and the only - there isn't one that's longer, or A2 length.  All the A2 is, is the A1 or "standard" rifle extension with a 5/8" spacer, and a 5/8" longer buttstock screw (hollow through the center). 

So, in short, don't waste a metric poop-ton of time trying to search out a specific receiver extension that must be A2 length.  You'll find a unicorn before you find that thing.  Just hunt for, and easily find an A1 length, or "standard" rifle receiver extension, and you'll save some serious heartache.

The Magpul PRS, both AR-15 and .308 AR, use the A1 extension, for what it's worth.

[AngusBagus]

I also have been looking at that product , but saying that , CLP and in some places ,gun  slick , don't have any lube problems .

+1 to Mobil 1 See below. This is my 1st Post at 308AR, but let me fill everyone in on all of my travails with my first DPMS. The rifle started out as a love/hate relationship, but now she's running sweet. Problems I had:

-FTFeed (getting a live round jammed halfway fed into chamber and causing sever mechanical damage) This was happening more frequently than just the next-to-last round.

-FTEject (needed a rod to push out empty casing)

I started down the "fix your mags" route and went with 2 PMAGs. They ARE awesome, but I was still getting the occasional FTFeed and multiple FTEjects. Same story with my modified DPMS mags. So I called DPMS and went through every potential fix. The guy on the phone who helped me said that 3 things should fix the problems, or at least help them before I would need to send in the upper/mags:

1. Lubricate the bolt carrier group (BCG) more than you could imagine. Literally put the BCG in a bowl/bottle full of motor oil (I used some extra Mobil Turbo Diesel Truck I had sitting around that I didn't need for an oil change). Let it drip dry, then assemble the rifle with it still coated and go to town. I couldn't bring myself to leaving it sopping wet with motor oil before firing, but I did clean it up a bit at home and drown it in CLP right before I chambered my first round.

2. Fix the feed lips on the DPMS mags. Easy... just take your time and move the lips a little at a time with some bull nose pliers. The primer should be at least 1/2 visible and centered. Test this with the "next to last" round in the mag. That is, load 2 and see how the 2nd round is sitting.

3. Assemble: drill, cleaning rod, steel wool wrapped around tip of rod. Insert into chamber and polish it. Don't try to turn it into 338... just polish it a little. According to the DPMS rep, they are notorious for having tight chambers and need to be helped a little bit sometimes to break them in.

After performing all 3 of these fixes for free (I already had the steel wool and oil sitting around), I went to the range to sight in my scope, burn some ammo with my red dot, and switch back to my scope to check zero. Sighted in with no issues. Switched to the red dot and I ran two 4-mag sets of CQB double-tap drills with only enough break between to reload my 4 mags. Then I ran 1 more mag through with the scope mounted back. The rifle was HOT, but no issues holding the zero when remounted and ZERO FTFeed/FTEject during the ~180-200 rounds.

AWESOME! I'm glad I didn't have to explain to my wife how much 308 ammo costs...  <laughs>

[RogerDane]

First post, great forum...

I just rec'd my R-25 Rem / DPMS in .308. Aside from not loving the Camo the price was 'very very' good and so I bit.

I was pleased to hear of others having issues with BCG and function because mine was so hard to open that at first I was looking for some release pin or something totally weird and new... nope. Just super sticky/gritty. Two hands and foot gritty. I took out the carrier and did some very careful polishing of the contact rails and tested. Took three or four passes with a felt, compound and 1000 grit wheel and finally I can pull it back left handed. However the charging handle is still very gritty. I think there is Camo 'overspray' making it rough.

Initially this AR had trigger (not mine) problems that were talked about in forums but mine is VERY smooth and breaks at 4+ to 5#... and again, smooth. I did lube some areas wtihin the group but I am happy with that pull.

The R-25 has been observed out to 1000 yds on steel, hits. It is accurate but I've not fired mine yet. Called DPMS about some other parts issues and they were helpful. They made the R-25 for Rem. and aside from the very gritty issues it seems like a fine AR. Will post after first use at range (the 1000 yard confirmed was with two friends who have the R-25 in same caliber, etc)

[imschur]

Im personally wrestling with a bolt thats a bit too snug in the carrier. Never personally seen this before. Ruined a day at the range.

[RogerDane]

So the bolt 'does not' move or move well in the carrier? Or is it the carrier just not sliding well with the handle? My new R-25's bolt is certainly more snug in the carrier than my 16 but I can still move it by hand and remove the pin/rotate bolt, etc... I use a "grease" on my bolt/bolt carrier contact points but might try a thinner lube.

[imschur]

My bolt is stiff in the carrier. Very hard to rotate compared to my others. So stiff  the weapon has difficulty locking and unlocking on an empty chamber. Im going to pull it apart this week. I oiled the crap out of it and greased the lugs. I cycled the action until my fingers were raw from the charging handle.

For testing purposes Im going to sawp bolts with another carrier to determine which part is the culprit

[RogerDane]

Understand. Good idea... I only have a AR15 bolt so not compatible ... I put a beefed up handle on mine as the stock on the R-25 was smallish and with optics on hard to reach... but even heavy duty does not make it nice and I am still working on "smooth."

[imschur]

Some handles are gritty due to the anodizing used. I have read that the gritty BCM gunfighters cause issues for some. As funds permit I am switching all my weapons to the MechArmor TacOps-1 mentioned elswhere on the forum.

[Dusty44]

All my guns,  my tools,  everything metal in my house gets coated with Mobil One Full Synthetic.  I let it soak in for as long as can be managed,  days if possible,  at least hours,  rarely minutes,  and wipe dry with paper towel.  Everything works smoothly forever and rust is almost forgotten.  After that initial soaking,  just lightly wipe with paper towel dampened with the oil after using/shooting and then wipe dry with other paper towel.

Outdoors,  the gate hardware for the fence has lasted a decade with two wipedowns with this oil,  the hinges still look good and do not squeak.  Without the Mobil 1 synthetic they would be junk in less than a year.  Take the battery terminals on your car apart and wipe all the metal surfaces with a drop or two of this oil.  No more battery corrosion.

I have found that when I shoot,  it is best to fire two to five 'warm up' shots to clear the barrel.  The lube is so slippery that the first few rounds do not get enough friction to reach full velocity.  After the 'warm up' shots,  all is well and consistent.  Clean up after is always just a few minutes.  That oil is right there in the pores and structure of the steel.  I use an undersize bronze brush wrapped in paper towel to a tight fit and soaked in powder solvent.  The bore is clean in just a few wipes.  That includes my AR,  bolt guns,  .22 rifle,  50 cal black powder and handguns.  More Mobil 1 before putting the guns back into storage.

I use a little oil can (Harbor Freight) and mix my Mobil 1 full synthetic with 25% to 35% Kroil (local gunshop,  MidwayUSA),  but the Kroil is overkill. 

[RogerDane]

A "lot" of folks swear by Mobil 1 - I've used Amsoil (auto application) synthetic for years and have over 200K on an F-150 - off subject - but I have not tried it on my guns. I have used Weapon Shield which "is" a synthetic and supposedly very invasive into the molecular structure, etc... I know that I get no rust at all, cleaning is quick but I've not done this on home hardware. Good ideas Dusty.

OF note on the R-25 and overall grittiness and feed of 'BCG' and charging handle... there seems to be a LOT of play upon pulling the handle fully out (up and down play seems greater than in my other AR types) and I see that "mechanics" can really cause some sluggishness and grabbing when racking the slide. If you do not keep it in line perfectly it will grab/grind and grate making it seem like there are smoothness issues but really it is mechanics. It would be nice if the 'channels' for the handle were supporting all the way out of the BCG tunnel.

Take care...

[mtbikerwvu]

I bought one brand new about 2 years ago that I no longer have, had it less than a week.  It had the same problems and DPMS seemed really less than interested, as you say tighten this, adjust that.  At one point I discovered that the gas block was loose and I thought I had figured it out, nope!  Now, my opinion, a brand new gun is not my responsibility to adjust and tighten.  It should function.  I took mine back to the dealer for a full refund.  That was my first and only experience with DPMS.  Although I would love to have one of the SASS rifles from DPMS I think the same guts inhabit both.  I now shoot a Armalite AR-10 and the difference between the 2, both brand new is amazing.  In 100 rounds I have had 2 failures to fire and both were ammo related duds.

[ErikS]

I have had an R25 for about 1.5 years.  I have never had a single issue with mine.  I have the little 4round mag that came with it and Pmags. All work.  Mine feeds and cycles with every thing I have fed it.  It also shoots .5 MOA, all day long using my hand loads.  It was tight when I first got it but after a few hundred round through it, it has smoothed right up.  The gritty feel of it cycling is in part caused by the much stronger spring and longer pull of the charging handle when compared to a AR15.  They won't feel the same, no way no how.

I feel the trigger sucks, .2 inches of creep is not conducive to good field accuracy.

I was not confident with the stock charging handle so I got a BCM gunfighter.

The Burris PEPR gave me the correct optics height. 

The camo will scratch so I put electrical a strip of electrical tape along the comb of the stock so the CH would not mess it up.

[zumabob1957]

Hey You All,

My good friend Nofail told me about this part of the site and he thought it would be helpful for me knowing what my trials and errors are.

To start I am building my own ar308 . For the most part its finished. I took it to the range and tried it out and had some success . Work in progress.

I shoot a few rounds and it jams. It seems to handle 3 different types of ammo the same.

By reading this site I have checked the bolt carrier clearing the ejection port. About 1/2" sticks out when the bolt is pulled all the way back. I think thats where the spent shells are getting dented.

I was suggested to get a CAR-10 buffer tube and spring.

I have also drenched the bolt carrier in Mobil 1 oil. I loaded 10 rounds in the mag and pulled the charging handle back hard and quickly. 2-3 at time and jammed. I realized I was resting the mag on the table so I repeated 10 more rounds and they ejected fine . Now I'm thinking I was resting the mag on the table while firing. I have a gunsmith checking out the gun this weekend. Hopefully this is going to be ironed out.

1. Oil the pss out of it with Mobil One.

2.New buffer  and spring (car-10)

3. Fix Samson quad rail (another story)

4. Open for your options or suggestions.

                                              Zuma Bob

[NeedAUserName00]

So I'm new to this site but ive been reading this thread for quite some time. I have a LR-308 24'' bull with the same issues. Lubed it, steel wooled the barrel, feed ramp, changed ammo, bought new mags. All the stuff you all recomended. Mind with barly 40rnds through it. I took it to the smith and he said my extractor was too long. It kept pushing the damn bullet against the walls of the barrel causing dents and making it look as if there were burrs on my feed ramp. Just something to look at for those of you with the same issue. BTW a lot of you are right one the gun is working properly, it runs fantastic.

[unforgiven]

Welcome from Indiana brother,long extractor? <munch>

[survivalshop]

Extractor too long & pushing the bullet , where?

The only thing that pushes against the cartridge is the bolt face or maybe a stuck ejector, that's not retracting into the bolt face & pushing the cartridge to the right side.

I would like to know more about this issue , some photo's if possible .