.308 barrel extension OD dimensions

[enduroed]

Am Looking for DPMS .308 barrel extension outside diameter dimensions and linear dimensions. Do not need the feed ramp dimensions for a solid model I am drawing. Any help would be greatly appreciated.

 

[LRRPF52]

Measurements taken from a DPMS 18” fluted SASS barrel I have sitting on a shelf.

OD: 1.186” (blueprints call for 1.88”)
Relief Cut step-down OD right behind the flange rear face, where the index pin is located: 1.170” (call out is for 1.169”)
From rear of the flange to the extension tail: 1.231” (call out is for 1.238”)
Overall Length: 1.932” (call-out is for 1.920”)

AR-10, SR-25, and LR-308 extensions are different in that they extend in front of the flange, unlike the AR-15. There is a section of the extension forward that blends with the barrel shank profile that is overlooked or generally-unknown to those familiar with the AR-15.

Here’s a diagram:

 

[longshot2000]

AR-10, SR-25, and LR-308 extensions are different in that they extend in front of the flange, unlike the AR-15. There is a section of the extension forward that blends with the barrel shank profile that is overlooked or generally-unknown to those familiar with the AR-15.

As you said, each is different. For the SR25, the OD is different on each side of the flange. Most barrels are not SR25 profile.