AR Sponsor
Posted: 12/26/2009 1:37:06 PM EDT
| I just got finished installing a set on my DPMS that I purchased off of the EE. Something just doesn't seem right about the lower rail. With the VFG installed it has about 1/4" to 3/8" play side to side. The upper is tight as it can be. Is this normal? |
| The slop is normal with 2-piece rail halves only held in place by delta ring pressure & the front end cap which is the case with the standard M4 RAS lower rail. If it bothers you then you can buy the KAC SAS lower rail that has the locking swing nut like the standard top rail has for the RAS. |
So two maybe three options here. One get the SAS lower as mentioned. Two Black zip ties ( dont worry you wont be the only one, trust me. Three, only if you are really desperate and the Delta ring wont go forward you can LIGHTLY file the barrel nut teeth to get that rail down far enough to actually lock down. However I have only seen this work twice before. Good luck and go buy some zip ties 
|
|
Quoted:
Is the locking tab correctly installed underneath the barrel nut? Quoted:
I just got finished installing a set on my DPMS that I purchased off of the EE. Something just doesn't seem right about the lower rail. With the VFG installed it has about 1/4" to 3/8" play side to side. The upper is tight as it can be. Is this normal? |
|
Quoted:
Quoted:
Is the locking tab correctly installed underneath the barrel nut? Quoted:
I just got finished installing a set on my DPMS that I purchased off of the EE. Something just doesn't seem right about the lower rail. With the VFG installed it has about 1/4" to 3/8" play side to side. The upper is tight as it can be. Is this normal? And yet: Quoted:
It is inside the front cap. After looking at it more, it almost seems like the delta ring is not sliding all the way forward on the upper or lower, but it won't go any further. Seems like it slide further forward on the standard hand guards. It's possible he's just got a tolerance stack leading to a loose rail, but installation error is just as likely. |
| FWIW pick out any of the ones in our racks of 100+ M4s and they will be like yours. Some are tighter than others but most have some movement in the lower rail. This is not a big issue as the PEQ15 is mounted on top or the side and retains zero there. Grips do not need return to zero ability. |
|
Quoted:
Quoted:
Is the locking tab correctly installed underneath the barrel nut? Tab is installed correctly, like I said the upper is rock solid. Sorry, meant the rear clamp, just to make sure you got it under the barrel nut correctly as more than a few people seem to do it wrong. I'd say take it all off and reinstall. http://www.quarterbore.com/library/pdf_files/kac_ras_inst.pdf If the bottom is still loose, it might just be a tolerance stack. |
AR Sponsor