choosing the rail length

[royta]

I was in a bad car accident a little over 9 years ago, broke my neck, and I now have a C4 spinal cord injury. I can still walk, just not well. Not wanting to give up all my hobbies, I'm putting together a lighter weight AR. My other AR is a 16" gov't weight with a FSB and a 9" DD Omega free float quad rail. I put it together in '08, and it's kind of heavy after the scope, Bobro mount, and rear BUIS. My plan is a BCM 16" ELW upper assembly, but I'm not sure whether to go with the 13" or 15" MCMR. I like the looks of the exposed barrel on the 13" setup, and I would think it's still plenty long enough to put a bipod at the end. With a 15", the legs of even a retracted short Harris bipod would extend past the muzzle. I've done some searching on this forum, and the majority seem to go for the longer rail.

This will be used for a relatively low rate of fire and mostly just a coyote rifle. However, I will be putting on a front BUIS since I'll be moving my rear site over. Maybe the 15" is what I need, and aesthetically, something I should just get used to?

Thanks for the advice and help.

Roy

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[jsbhike]

Everything is a trade off.

The longer rail should give you more control over recoil *if you grip further forward* in addition to the bipod being steadier.

If you don't grip further forward then the increased control from the 15" length goes out the window.

The further out anything gets attached the heavier it will feel.

[Sooter76]

I use the 13 inch rail myself… Like you. I just like the aesthetics. That said, with the MCMR 13 I can still get full extension of my arms on the rail when shooting and have full control of the recoil.

I’d go with the 13…

[titsonritz]

Have you considered a 14.5"? When I was shopping around for a LW upper I end up with a BCM 14.5" ELW BFH w/ MCMR-13 (https://bravocompanyusa.com/bcm-bfh-14-5-mid-length-enhanced-light-weight-upper-receiver-group-w-mcmr-13-handguard/), it has been a great upper. I go back and forth on whether I'm going swap out the M-LOK HG for QFR-12.

I am currently building an upper 13.9" Criterion Core Barrel with a 10.75" handguard, because I wanting to keep the balance of the gun toward the shooter.

On a side note, have you tried using taller mounts for your optics? I have found I really like 2.26" tall Unity mounts for my red dots and 1.93" mounts for my LPVO for keeping my head up and less strain on my neck. Check it out if you haven't.

[trauma]

-Daniel Defense makes a 16" light weight profiled barrel you could use.https://danieldefense.com/16-5-56mm-mid-length-1-7-lw-profile.html

-Midwest Industries makes a lightweight rail as well with a Titanium barrel nut. https://midwestindustriesinc.com/mi-ultra-lightweight-one-piece-free-float-handguard-m-lok-tm/

With how good modern optics are, you could just skip the BUIS to save some weight.

The longer rail thing is helpful for lasers being as forward as possible and combating shadow from white light but it sounds like that isn't what you're needing.

I think the shorter rail is exactly what you need.

[Todd.K]

I think most people chose extra long rails for aesthetics. You would probably know if you actually needed more than 13” of rail.

[RWH24]

I have a BCM 14.5 ELW BFH, ext A2 P&W and the 13" KMRA. It is my go to grab and Go.
70252

My BCM 16" ELW BFH has the 15" MCMR and BCM MD.

Even on a 16" barreled upper, I prefer the 13" rail. Each his own decision for personal preference.
I also have a BCM LW Mid length with pinned FSB and a Centurion C4 rail. This is on a COLT CR lower from Brownells YEARS ago.

A 16" barreled upped makes more sense and less issues if your redress your upper very often. I ordered my 14.5, P&W Exactly like I wanted so no need to change her wardrobe.

[Clint]

Our general recommendation is to size the hand guard 1" less than the barrel length, up to a maximum of 13".

[Sidneyious]

If you want to stay 16" barrel a "mock dizzy" with a light weight barrel would be cool.
I did a 14.5 with a gov m4 profile barrel, 11.25" handguard from troy with a milspec barrel nut.
I still need to get around to securing my front sight block. I have a hs503cu(t1 ish copy) on it for now, its kinda balanced

Its lighter than my 10.5 with a lot of stuff on it.
My 12.5 aero/BA with p4xi and ADM mount honestly weights about the same.

I dont have a fused anything yet and our of my 4 ars I like the handling of my 14.5 the most but I did build this to be a basic bitch build from parts and didnt even bother looking at weight.

I have major back problems and a very very high tolerance for pain.Im sure light weight barrels would help with a lot but I aint about to rebarrel 4 guns at this point so I will suck it up and suffer.

This is an older picture but it checks out
https://i.ibb.co/xMB25QY/IMG-20230419-141947705-HDR.jpg (https://ibb.co/FByh7tX)

[Hammer_Man]

Go with the 13” rail, especially if weight is a big concern.

[royta]

I gripped my current 16" mid-length at the bottom of the FSB, and even further, to see if I'd actually need a 15" rail. For somebody with long arms, I can see the benefit of a 15" if there was a bipod at the very end because then you can grip just behind the bipod, but I'm only 5'7" with correctly proportioned arms, and I was really reaching when gripping 13" out. Even though the 15" rail is only 1 Oz heavier than the 13" (measures 13.4") rail, I think going with the 13" is the way to go. Yes, a longer sight radius is appealing, but even a standard 20" A2 has a shorter sight radius than what there is with a 13" rail. Upon further measuring, my FSB post is 1.5" past the end of the 9" rail. So a 12" rifle length gas system would have the front sight post at 13.5", which is where a backup sight would be on a 13.4" rail. Close enough, anyway.

Now I have to impatiently wait for the assembly to get in stock.

I'm currently researching tools, blocks, rods, etc. to make things easier to put this together.


Thanks for the help.

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[royta]

I wasn't getting the best communication from BCM regarding an ETA for the MK2 BFH 16" ELW w/ MCMR-13 handguard, so I ended up ordering the setup with the 15" handguard. I figured that by the time the 13" was in stock, the free BCG deal would be over. So now I can buy a 13" handguard by itself and sell the 15". I really wanted that MK2 upper and 16" BFH ELW barrel.

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[Disciple]

sorry, reading comprehension fail

[AndyLate]

Optic and mount choices will affect weight more than 2" of rail. FWIW, I prefer a 13/13.5" rail on a 16 inch barrel, but purely for my esthetic taste. There is no law against mounting the bipod far enough back on the rail to keep it short of the muzzle.

Andy

[royta]

Optic and mount choices will affect weight more than 2" of rail. FWIW, I prefer a 13/13.5" rail on a 16 inch barrel, but purely for my esthetic taste. There is no law against mounting the bipod far enough back on the rail to keep it short of the muzzle.

AndyI like the look of the shorter rail too. 1 Oz difference between the 13" (13.4") and 15" is definitely no biggie, but to me, the 15" looks bad.

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[ViniVidivici]

I've seen examples of 16" middys with 11" and 12" rails that work just fine. Aesthetically, I like 'em that way.

Wouldn't want any longer than 13" on one, for sure.

[titsonritz]

My buddy has a SIONICS 16" LW with a BCM MCMR-10, it is freaky light weight.