Do you own a micrometer?

[Robocop1051]

@Matt.Cross... @98Z5V... I'm calling you guys out first (mainly because I called R2 last night, so he's off the hook).

Anyone that wants to participate is welcome here. I'm trying to get an idea of the difference in measurements between lowers. This number could determine the compatibility when mixing uppers and lowers from different manufacturers.

 

I need both measurements "A" and "B". So far my numbers for measurement "A" shows AR-10B @ 1.61" and the LR308 @ 1.54".... I'd love to know your results. The B measurement could vary even more greatly (even with perfectly compatible receivers) due to the unpredictability of the 308AR receiver spec's.

Please list your make/model with your measurements.

[Matt.Cross]

I think that can be done without much difficulty.

[Boot_Scraper]

PA-10 Gen II

A= 1.570" (+/- .002")

B= 2.155"

[sketch]

matrix 7.62

A: 1.570" (+/ - .002")

B: 2.277" 

[Robocop1051]

I am going to be using this information in the design of my lower receiver, so I can be as compatible as possible with all LR-308 style upper receivers. 

 

I haven’t forgot about you Ron. There’s still a possibility of an AR-10A  in the future 

[98Z5V]

Well, you've got the AR10B, Matrix Aerospace, PSA Gen 2, DPMS LR-308...  I can add the Aero Precision M5 to the mix. Lemme dig one out.

[98Z5V]

1 hour ago, sketch said:

matrix 7.62

A: 1.570" (+/ - .002")

B: 2.277" 

Is this the Matrix with the angled-cut receivers, like an AR-10, or is this the new Matrix stuff with the rounded DPMS cut?

[98Z5V]

Aero Precision M5 receiver.

A = 1.477"

B = 2.277"

That's off one of Rob's favorites...  

[Robocop1051]

41 minutes ago, 98Z5V said:

That's off one of Rob's favorites...  

This rifle is so badass! 

[edgecrusher]

I’ll get you Mega, PWS, and LaRue tomorrow. I’m smoked and we are starting early tomorrow.

[sketch]

4 hours ago, 98Z5V said:

Is this the Matrix with the angled-cut receivers, like an AR-10, or is this the new Matrix stuff with the rounded DPMS cut?

not rounded dpms hi rail.

Edited May 25, 2018 by sketch
Shits

[98Z5V]

Yep, that's the same version that I have.  No need to pull mine out then. 

[edgecrusher]

LaRue- A-1.5030.         B- 2.1430

PWS A-1.5030.              B- 2.2560

Mega MaTen A- 1.5395.   B- 2.2600

Measurements for A done with a steel square on top of where B measurements were taken. B measurements were top to bottom clamped.

[Robocop1051]

I guess I should add mine...

SI Defense (do they even make rifles anymore?)

A. 1.45”

B. 2.25”

[Rsquared]

On ‎5‎/‎24‎/‎2018 at 8:21 PM, Robocop1051 said:

I am going to be using this information in the design of my lower receiver, so I can be as compatible as possible with all LR-308 style upper receivers. 

 

I haven’t forgot about you Ron. There’s still a possibility of an AR-10A  in the future 

Does that mean you're gonna give me an AR-10A?  All of mine are B's, but I'll always take a FREE rifle from a "friend"