LMT MRP Upper Question

AR/M4 AR General Discussion
1

Hey All,

I currently have an MRP CQB upper and I’m planning on picking up another MRP upper for a new rifle.

I currently have 3 barrels for the CQB (.204/5.56/6.8) upper.

I’m wondering if I get a rifle length MRP upper if I can swap barrels between uppers?

2

You can. If you go too short you won’t be able to seat the barrel because your upper will shroud the end of the barrel.

3

Yes, but FYI, pistons will only work in the CQB…

4

Any and all MRP barrels will work in conjunct w. the CQB chassis.

The Rifle length chassis will only support the following barrels…
14.5" CL 5.56, 16" CL 5.56, 16" CL 6.8, any Rock SS barrel will work as well including your .204 Rock SS barrel.

So no piston, or no barrel under the length of 14.5" for the rifle length chassis.

5

I was looking at the LMT catalog a couple of nights ago and thought I saw a 12.5" barreled 6.8 option that looks like it would work with the rifle length MRP.

If a 12.5" DI would work in the MRP rifle length, that would be nice in a 5.56 I think.

6

The rifle length MRP chassis has a “rail” equivilant to almost 14"…that is why rifle length chassis’s only support barrels longer than 14.5".

7

I have a 22 Long Rifle barrel in a rifle upper and people think it is an SBR. Looks kind of funny. I love that LMT one piece rail. I can mount anything anyway I want.

8

I maybe wrong but I thought the CQB was 9" and Rifle was 12"

I know my CQB is the same length as my larue 9.0, of course the MRP has more rails because its one piece.

9

The CQB is 9 3/4"…rifle length is 13 3/4". I own both:)

10

10-4, love your pics btw :slight_smile:

11

Thanks :slight_smile:

Cannot wait to join you gents in the 10.5" club…waited a long time to be a member.

12

Love mine! You will not be disappointed!

13

The rifle length MRP is indeed very long, note the length of the exposed barrel (not much of it)

14

Does the “rifle length” MRP upper use a rifle length gas system or mid-length?

15

Gas is determined by which barrel not the chassis length. The 16 and 18" 5.56 DI barrels use the mid-length gas system. The 10.5 and 14.5" 5.56 DI barrels use the carbine length gas system.

16

So the “rifle length” MRP can use the 16 and 18" barrels with mid-length gas systems?

17

Sure thing. The gas blocks on the MRP barrels are low profile and fit inside the chassis as designed. Here is a pic of a rifle length chassis with a 16" barrel.


18

I own a rifle length 16" MRP. I was surprised by that length. I never bothered reading the rails length and ASSumed that all rifle length rails were 12", regardless of maker. Guess not. It probably explains why they are a little heavier than an average 16 " Middy.

19

and the MRP gov profile is a little beefier than the reg Gov Profile.