dpms build help

[latewatcher]

i attempted to build my first .308 and decided to use all dpms parts for availability.  i bought the lar .308 upper at knob creek.  i bought the lower at a gun shop and got the lower guts, buffer, tube, and spring from brownells.  i assembled it and it looked right until working the bolt group.

the bolt group will not go back far enough for the bolt catch to work. the bolt group goes back just the front of the bolt group and not the bolt for it to lock properly.

i used the .308 buttstock kit from brownells and contacted their tech staff. i am a big fan of brownells but i think i stumped them. 

to experiment, i put a short carbine buffer in the tube and it locked up when i pressed the catch and worked with an empty mag.

could i have used the wrong buffer tube for length?? i have the correct buffer for .308 and the correct spring (i hope!!)

all advice, ribbing, and constructive criticisms welcome.

[TacBlade]

This could be an explanation to the Charging handle I have?  I have one that is about a 1/2" longer than all others and I believe it is for a LAR setup?  Maybe?

[TacBlade]

Cancel that thought, I found the old for sale post and it is a Rock River Arms Charging handle.  Now for your situation?  I would think it is the wrong buffer and spring? Take  the buffer and spring out and see how far you can get the handle to pull the bolt back.  If it works, it is the buffer and spring.  The buffer is slightly longer on a AR15 Carbine setup, so you might want to measure your buffer and I can measure mine and let you know what the length is.

[survivalshop]

Need more info on what stock you have , Carbine ( collapsible) or std. rifle.

If its a DPMS type , you can use the corresponding AR 15 receiver extension (buffer tube ) carbine(collapsible ) or rifle .

Here's the big ,BUT  you will have to have the right 308 spring & buffer for the particular stock configuration.

Armilite uses the same spring for both & may need modification to work in any of the DPMS types.

[DocLarsen]

latewatcher,

Deja Vue all over again!  See: Bolt Carrier Slipping off Catch

Regards,

DocLarsen

[latewatcher]

hey sir, i posted the thread before i went fishin.  i read it and got some out of it.  i hope to find a solution soon.  all kinds of things to experiment with. sigh. kind of a let down though. i built a few ar15s and did not have a glitch one.  oh well.

[98Z5V]

i attempted to build my first .308 and decided to use all dpms parts for availability. i bought the lar .308 upper at knob creek.

Okay, that LAR upper is from Rock River Arms.  That's not DPMS-style parts, and could cause you some problems, if the rest of the gun is DPMS-based.  I honestly don't have too much familiarity with the RRA 308 guns, and based on how different they are from the others is why I've personally stayed away from them.  Not any kind of judgment about their quality on my part, at all - just the reason I haven't been attracted to them enough to try to put one together.  Just understanding the differences between AR-10 platforms and DPMS-based platforms is enough to keep me busy.  <laughs>

Here's what RRA has to say about it:

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=451&CFID=106381829&CFTOKEN=14101763&jsessionid=f030cf254d2763245e58

[latewatcher]

thanks for all the replies.  happy turkey day everybody!! ;D