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View Full Version : Swapping to BCMs KMR rail- Cost considerations


asolo
04-02-14, 16:06
I've currently got 2 BCM rifles, one middy 16" and one 11.5" BHF both with DD omega rails- 9" and 10" respectively. The 16" has a front sight base on it so I'm wondering what would be the most cost effective thing to do: sell the 16" complete upper sans CH and BCG and buy a new upper from bcm or take the rail off, put a low pro gas block on?

Seems like used DD rails are going for pretty cheap but I think I may be able to get more for my money if I sell the upper together plus I can upgrade BHF ELW for my new upper:).

Thoughts?

Thanks.

Edit: sorry, need to clarify- I would like both rifles to have the kmr rails. 13" on the middy and a 10" kmr on the 11.5 upper
GH41
04-02-14, 16:22
What is your goal? How much are you willing to spend to achieve your goal?? GH
markm
04-02-14, 16:23
If you want to get the light barrel and rail... yeah... you're probably best off selling the whole upper.

You could do a straight 10.0 swap on the 10" omega too.
asolo
04-02-14, 16:26
My goal is to have identical ARs other than barrel length. With the sale of whatever parts, uppers,etc and the addition of the KMR rails I'd like to keep my total out of pocket expenses less than $250-$300. The 10" dd rail is unused and the 9" is in damn near perfect condition.
Vegas
04-03-14, 11:09
I went through the exact same drill and the cost was very close either way. In the end I decided on getting rid of the whole upper because it meant I got shiny new BCM'ness all over. My DD BCG went with the upper too.
PigNorton91
04-03-14, 11:14
My goal is to have identical ARs other than barrel length. With the sale of whatever parts, uppers,etc and the addition of the KMR rails I'd like to keep my total out of pocket expenses less than $250-$300. The 10" dd rail is unused and the 9" is in damn near perfect condition.

Do you not want to modify the stock fsb ?

Seems like It would be an easy fix to just shave down the fsb then install the DD rail. My only gripe with the lo pro gas blocks is that many of them do not pin to the barrel or require a gunsmith to do so (or a maybe you have the skills/tools?)

This is one of the reasons I have been looking at a DD M4V7 upper as opposed to the BCM middy with Kmr 13.5

The DD comes with a pinned lo-pro while the bcm comes with the set screw lo-pro I believe (someone chime in)

From my experiences I have seen lo-pros come loose (maybe installed wrong?) but I feel much more confident in a pinned fsb for durability and reliability.

If you already have a dremel this would be a cost free route expect your time and maybe some paint.

Just a thought, I went through this same issue and decided to mod the fsb.

Hope this helps.
asolo
04-03-14, 22:38
Do you not want to modify the stock fsb ?

I hadn't given that very much consideration honestly. I've heard of it but don't know exactly how to do it. Yes, I have a Dremel among other tools, however I don't have the knowledge or skill to take off the fsb myself and put a low pro gas block on. Guess I better figure that info the equation.

Sounds like the 2 best options are shave the fsb or sell the whole upper and order a new one.

Thanks very Much for the insight guys.
PigNorton91
04-04-14, 01:23
I hadn't given that very much consideration honestly. I've heard of it but don't know exactly how to do it. Yes, I have a Dremel among other tools, however I don't have the knowledge or skill to take off the fsb myself and put a low pro gas block on. Guess I better figure that info the equation.

Sounds like the 2 best options are shave the fsb or sell the whole upper and order a new one.

Thanks very Much for the insight guys.

Shaving it down is easy if you have used a dremel tool before.

Cut off the sight with a hack saw, then shave down the fsb on top, and on bottom (boyent mount)

should come out looking like this:

http://i61.tinypic.com/2dkmwjr.jpg

this would be a really easy job and you wouldn't need to buy any parts at all. by the way, I have seen people do this without even removing the fsb.

Hope this helps!
markm
04-04-14, 08:41
this would be a really easy job and you wouldn't need to buy any parts at all. by the way, I have seen people do this without even removing the fsb.


FSB would have to come off at some point for the new barrel nut anyway... but it has been done mounted.