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Page AR-15 » AR Variants
AR Sponsor: bravocompany
Posted: 3/8/2010 7:34:08 AM EDT
I recently purchased DPMS LR-308 Classic and after cleaning it and firing it for the first time I experienced some severe feeding issues. Every third or fourth shell would end up at an angle in the chamber with the bolt contacting the middle of the body of the brass. I contacted DPMS and they asked told me that I needed to oil the bolt and chamber untill it was "dripping wet". It has been my experience with AR-15's that is better to use a light oil application.

Is the advice from DPMS correct? Should I leave the bolt and chamber "dripping wet" with oil?
Link Posted: 3/8/2010 7:42:25 AM EDT
[#1]
Oil the bolt and bolt carrier until drippy. DO NOT oil the chamber. A dab of grease on the backs of the bolt lugs doesn't hurt either.

Once the BCG breaks in, you can reduce the amount of oil to the same level you use in an AR-15.
Link Posted: 3/8/2010 9:01:25 AM EDT
[#2]
Sounds like more of a mag issue than a lube issue. Have you tried multiple mags (other than the 1-2 that came with the gun)
Link Posted: 3/8/2010 12:10:18 PM EDT
[#3]
I looked around some forums and several people attributed the problem to the factory mags also. I have only used the DPMS factory mags as of yet. I did order a MagPul Pmag this weekend to try.


I will lubricate it like you said but the DPMS guy was very emphatic about not using any grease. I guess I can try it both ways.
Link Posted: 3/8/2010 1:17:04 PM EDT
[#4]
Quoted:
I looked around some forums and several people attributed the problem to the factory mags also. I have only used the DPMS factory mags as of yet. I did order a MagPul Pmag this weekend to try.


I will lubricate it like you said but the DPMS guy was very emphatic about not using any grease. I guess I can try it both ways.


I run the bolt and carrier fairly wet in mine and it works. Only about 300 rounds through it but seems to be breaking in. I had the same feed issues you did with one DPMS mag, but it was only on the second to last round in the mag. A minor tweak to the feed lips and it was good to go. Since then I got three of the magpul mags, The DPMS mags are dust collectors at this point.
Link Posted: 3/8/2010 2:04:32 PM EDT
[#5]
I recently returned a rifle with a short throat to DPMS.  I had never reported, nor experienced any feeding issues.  However, DPMS did absoutely NOTHING regarding the short throat..in fact, they wouldn't even tell me what they did to investigate the issue.  I was short stopped by customer service, and never allowed to speak with, or have questions passed onto the gunsmith who may have checked the  short throat..

In any case, all DPMS did was say that they replaced my magazine as they had feeding issues, and they cleaned the rifle.  I appreciate their cleaning it as I sent it in clean...I would rather that they left me with the magazine and dealt with the issue I had returned the rifle for..

Guess I will have to look into this and pay a gunsmith on my end to check it out.   I am extremely disappointed in DPMS's failure to either: 1.  tell me what they did to investigate the single thing I sent the rifle in for, and  2.  Leaving me with the feeling that it will be up to me to deal with the short throat.

I always thought that when rounds stick in the chamber, and extracted rounds come out with the lands and grooves engraved on the bullet, that is a short throat...

I never did have feeding issues though, that is the reason this is in this thread.  Apparently, DPMS feels that feeding issues are an easy fix...so send them your rifle..
Link Posted: 3/8/2010 2:27:30 PM EDT
[#6]
Quoted:
I looked around some forums and several people attributed the problem to the factory mags also. I have only used the DPMS factory mags as of yet. I did order a MagPul Pmag this weekend to try.



Dissasemble the magazines, clean the flash from around the follower. I used an emory board and a razor.
I can't explain it, I don't know why, but I had exactly the same problem you did. I was using DPMS 5rd magazines. I didn't think to bring the 20's with me to the range, so my first trip was the suck.
My second trip proved better after cleaning up the mags.
I've since received some C Products mags, and MagPul P-mags but have not had the chance to try them.
Link Posted: 3/9/2010 8:13:14 AM EDT
[#7]







Quoted:




I recently purchased DPMS LR-308 Classic and after cleaning it and firing it for the first time I experienced some severe feeding issues. Every third or fourth shell would end up at an angle in the chamber with the bolt contacting the middle of the body of the brass...




With no mag in place, if you pull the charging handle all the way back, then ride it forward until it's more than half way there and let go, does the bolt close fully or get sort of stuck out of battery? I had a problem similar to yours and apart from the traditional DPMS mag problem, I also found a lot of friction points between the bolt carrier and receiver which used up the cycling energy of both the gas system and the buffer spring. Indeed, if the bolt didn't go back far enough to pick up a new round the normal way (i.e., short stroke), the bottom of the carrier was rough enough to drag the top round forward so that it cleared the mag lips and got jammed as you describe.
The solution was to sit in an easy chair with just the upper and open and close the bolt with the charging handle for an hour or two. Do that and you'll see a lot of wear points on the carrier begin to shine. Also, use very fine grit paper to shine up the parts of the bottom of the carrier that rounds in the mag (both left and right) rest against, so that the carrier will slide over them rather than drag them along. When done, the bolt will be closed by the buffer spring even if it's already almost there, but the rounds will be left in the mag unless the bolt is far enough back to pick one up.





 
 
 
Link Posted: 3/9/2010 8:54:40 AM EDT
[#8]
Send your factory mags back and they will send you new ones with improved followers.They are very good about it.
Link Posted: 3/9/2010 12:34:58 PM EDT
[#9]
As said before, switch to Magpuls and run the bolt WET untill broken in.
I had the same issues.
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