Centurion CMR or BCM KMR-A?

[straitR]

Without saying what the temp of the rail was, that info doesn't seem helpful. A quick few mags dumped shouldn't heat up much, but 5 or 10 minutes later the heat should have sunk in nicely and then things start to matter.


Just another way to look at things. I have both rails and enjoy each. When it comes to what cover does best for knocking around and heat protection or grip, it is very difficult to beat the CA covers. Yes, they are thicker, and I can see where that would matter to some people, especially those with tiny hands.

Agreed. That said, the CMR has a smaller OD width than the KMR. Adding the CA panels to their CMR isn't that bad, even for small hands, IMO. Although the CA panel design is excellent, if I were trying to keep the smallest OD possible or had smaller hands, I wouldn't add the CA panels to anything but a CMR.

If memory serves me, I liken the CMR with their panels (at 3-6-9) to roughly the feeling of a bare URX4 as far as thickness. Feel is subjective though.

[Stickman]

Agreed. That said, the CMR has a smaller OD width than the KMR. Adding the CA panels to their CMR isn't that bad, even for small hands, IMO. Although the CA panel design is excellent, if I were trying to keep the smallest OD possible or had smaller hands, I wouldn't add the CA panels to anything but a CMR.

If memory serves me, I liken the CMR with their panels (at 3-6-9) to roughly the feeling of a bare URX4 as far as thickness. Feel is subjective though.

Agreed on all accounts.

[ABNAK]

Without saying what the temp of the rail was, that info doesn't seem helpful. A quick few mags dumped shouldn't heat up much, but 5 or 10 minutes later the heat should have sunk in nicely and then things start to matter.


Just another way to look at things. I have both rails and enjoy each. When it comes to what cover does best for knocking around and heat protection or grip, it is very difficult to beat the CA covers. Yes, they are thicker, and I can see where that would matter to some people, especially those with tiny hands.

LOL I see what you did there! No, not the issue with me. I like to use a modified "C" grip with my forward hand so a smaller profile enhances that.

[jwfuhrman]

Owning both, my vote is the KMR-A. The CMR I have on my 6.8 is so tight inside its touching the gas block. I've tried taking it off and then on again, tried the barrel/rail combo on 4 different uppers (including 2 BCM demo uppers) thinking the Anderson Mfg upper I built the 6.8 on was out of spec but it doesn't matter.

Other than that, the CMR is a damn good rail, just not sure what the issue is. Swapped it for a KMR-A in 13(same length as CMR) and the barrel centers perfectly and the gas block on rail issue was solved (BCM LP Gas Block, Daniel Defense 16in 6.8 S2W barrel).

[Jwknutson17]

Owning both, my vote is the KMR-A. The CMR I have on my 6.8 is so tight inside its touching the gas block. I've tried taking it off and then on again, tried the barrel/rail combo on 4 different uppers (including 2 BCM demo uppers) thinking the Anderson Mfg upper I built the 6.8 on was out of spec but it doesn't matter.

Other than that, the CMR is a damn good rail, just not sure what the issue is. Swapped it for a KMR-A in 13(same length as CMR) and the barrel centers perfectly and the gas block on rail issue was solved (BCM LP Gas Block, Daniel Defense 16in 6.8 S2W barrel).

Have you tried the Centurion gas block? From the centurion site, it states...


***IMPORTANT PLEASE NOTE***
- Currently our gas block is the only one that Centurion Arms can guarantee to fit under the CMR. This is due to the CMR's extreme low profile.

[Vegasshooter]

When I went with the Centurion rail on my BCM Stainless barrel, I had to use the Centurion gas block. The BCM block would touch as well. $35 later, viola, no touching. The Centurion gas block is that much more compact that it completely clears 360*. Just as a FYI.

[jwfuhrman]

Have you tried the Centurion gas block? From the centurion site, it states...


***IMPORTANT PLEASE NOTE***
- Currently our gas block is the only one that Centurion Arms can guarantee to fit under the CMR. This is due to the CMR's extreme low profile.

Good to know!

[ziklag]

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Guess the measurement isn't much help without KMR-A numbers to compare... maybe someone else can give those.

The Centurion covers mitigate heat much better than the Magpul covers I used before they arrived. Never used the BCM so can't comment on those.

[sig1473]

I will echo JW's experience. I was building up a BA 14.5" and tried to use a Geissele GB with the CMR 13" MLok. The gas block touched the rail. I've since moved on with the project and put on a different rail. I just now need another barrel maybe and get a Centurion GB for another build with the CMR.

[bowman57_2]

I’ve got a BA gas block under my CMR and it’s pretty tight on the bottom but still doesn’t touch the rail anywhere.