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Gunsmithing 9. HOW-TO: Ultimate AR: DPMS LR..... Idiocity fix

Hellbender

Gunny Sergeant
Full Member
Minuteman
Apr 23, 2008
1,558
315
Lebanon, Missouri
Part 9:

IDIOCITY, ie STUPIDITY...definition: med. jur. That state of the mind which cannot perceive and embrace the data presented to it by the senses; and therefore the stupid person can, in general, form no correct judgment. It is a want of the perceptive powers. Ray, Med. Jur. c. 3, Sec. 40. Vide Imbecility.


This post concerns the DPMS LR series rifles only.

DPMS decided to use the standard AR15 bolt catch and button on the LR series rifle, even though the receiver is almost 1/4" wider at this point.

This results in the stock ALUMINUM button usually having only 2 (TWO) threads engaged...... CHECK YOURS!!

This is a major malfunction waiting to happen....please reference definition above.

Anyway, this is how I fixed it; buy an extended STEEL button, this is the one I used......

http://www.brownells.com/.aspx/pid=18770/Product/AR_15_M16_EXTENDED_OVERSIZED_MAGAZINE_RELEASE

Take a file or a belt sander and cut off all the "oversized" part, making a long, standard sized button.

This will allow at least 4-5 STEEL threads to secure the button, it's a little higher than stock, but you could cut it down more if you wanted it shorter.

DSC00061.jpg


 
Re: 9. HOW-TO: Ultimate AR: DPMS LR..... Idiocity fix

Vux51- With only having a few threads engaged, I feel better having a steel part in this application.

The real problem is the standard AR mag catch needs to have .200" longer threads.
 
Re: 9. HOW-TO: Ultimate AR: DPMS LR..... Idiocity fix

Seems like with only a few threads engaged material is not important. Steel would definetly be better. If you could get full contact then aluminum would be OK, I guess. This looks like a fairly easy part to make. I'm installing a new trigger so it would be the time to look at it. Thanks for pointing this out. I wonder what Armalite uses?
 
Re: 9. HOW-TO: Ultimate AR: DPMS LR..... Idiocity fix

Armalite (I'm going from memory, as it been over 10 years since I owned an AR10) has a specific AR10 mag catch to fit the M14 angled side mags. It's a different part that wouldn't work on the parallel sided KAC/DPMS mags.
 
Re: 9. HOW-TO: Ultimate AR: DPMS LR..... Idiocity fix

thxs for the heads... i found the lwrc repr having the same trouble so i added a {moded D shape] steel mag release now no more mag troubles...