Which Upper?

[USGILT]

Trying to decide between the following BCM uppers –

BCM Standard 16" M4 Upper Receiver Group w/ Daniel Defense Lite 10" Handguard

http://i187.photobucket.com/albums/x192/USGILT/BCM-URG-M4-1620DDL10-3.jpg


BCM SS410™ 16" Mid Length Upper Receiver Group w/ Daniel Defense Lite 9" Handguard 1/8 Twist

http://i187.photobucket.com/albums/x192/USGILT/BCMSS410MidLengthUpperReceiverGroup.jpg


I am trying to go for the lightest upper between the two. I will be running a TA33R-8 ACOG 3x30 as an optic and primarily shooting Prvi Partizan 5.56 M855 FMJSCBT 62gr ammo. Wondering what the difference in accuracy would be between a 1x7 twist barrel and a 1x8 twist barrel. Both have daniel defense lite rails one is a 9” and one is a 10”. One is a carbine length gas tube and one is a midlength.

Any thoughts would be appreciated thanks,

USGILT

[Robb Jensen]

If M855 is the ammo you'll be using I'd recommend a chrome lined barrel. There's no reason to use a match grade barrel with ammo that's really designed for belt fed machine guns.

[YVK]

Must of hit 9 instead of 7 wonder if their is anyway to edit that? Any particular reason why you prefer a 10" rail vs a 9" and a low profile gas block? I was thinking of replacing the FSB with a ARMS #41 B-L Silhouette Folding Front Sight.

Thanks,

USGILT


USGILT, it looks that my post and your response disappeared; perhaps, something to do with editing the poll. I am quoting an email notification text.

I keep my support arm far out and high up on the rail. The tumb comes in contact either with FSB or rail mounted sight. FSB, being a gasblock, gets hot with sustained fire - OK with gloves, not so much with bare hands. 10 inch rail covers gasblock almost completely on midlength. No contact with gasblock is possible and heat transfer is reduced - makes my support hand happier and less dependent on glove use.

Additional issue is placement of a weapon light. I like mine at the very end of 10 inch rail. Frankly, on my one midlength upper that has FSB I don't even use railed forearm: the light gets attached to FSB itself via MI mount, and railed forend in this situation is nearly useless for me.

[USGILT]

Both of the above uppers have crome lined bores and chambers. I am primarily shooting M855 for pratice and hope to move up to some heavy grain stuff latter.

USGILT

[USGILT]

YVK

So I am thinking that you do not use a VFG?

[YVK]

YVK

So I am thinking that you do not use a VFG?

I use it, but I don't grip it; I do worse when I grip VFG. I've used a TangoDown stubby VFG for a while, and recently I cut it for a "super-stubby" length. I also use KAC fingerstop.


Both of the above uppers have crome lined bores and chambers.

I'd be highly surprised if their SS410 bbl had any chrome in it. You might want to check with BCM on this.

[BB01]

I agree with YVK, that SS barrel is not going to be chrome lined...

You may want to look at this:
http://www.bravocompanyusa.com/BCM-16-Mid-Length-Upper-Receiver-Daniel-Defense-p/bcm-urg-mid-16%20ddl9.htm

[Quentin]

I didn't vote since there wasn't a choice for 'neither'. For my build I didn't want stainless or the carbine gas system. I went with a midlength chrome lined upper like BB01 linked above. Mine was ArmaLite but otherwise is similar.

[USGILT]

Looks like your right, the stainless barrels are made with 410 stainless which BCM states is a harder and more corrosion resistant than the conventional 416 stainless found in most barrels. No mention of chrome lined barrel or chamber as with their standard barrels.

USGILT

[8200rpm]

There is no sense in getting a M4 profile 16" barrel with a carbine gas system. Go for a midlength gas system with a chrome-lined barrel. gotm4 is right; there is no sense in getting a stainless barrel unless you're shooting predominantly match grade ammo.

Since you want to run a TA33R-8, get an upper without a fixed FSB...

http://www.bravocompanyusa.com/BCM-16-Mid-Length-Upper-Receiver-Daniel-Defense-p/bcm-urg-mid-16%20ddl12.htm

You will see a "ghost" of your FSB through the 3x ACOG. The FSB serves no use while looking through the TA33R-8... it's one or the other whereas in the case of an Aimpoint, you can employ the front sight in conjunction with the Aimpoint if needed.

[USGILT]

Whats the weight difference between a 9" daniel defense rail and a 10" or 12" like which is in the link you provided? I am trying to keep the weight down as much as possible.

USGILT

[8200rpm]

Whats the weight difference between a 9" daniel defense rail and a 10" or 12" like which is in the link you provided? I am trying to keep the weight down as much as possible.

USGILT

DD Lite 9" = 11 oz.
DD Lite 12" = 14 oz.

According to www.DanielDefense.com

[RogerinTPA]

Another vote for the Middy with the DD Lite 12 rail, maybe the BFH (Hammer Forged Barrel) for shits and giggles, also with the DD12 Lite rail. I like to get my support arm extended further out and I like the additional real estate.

[M16MANIAC]

I didn't vote
I would go with a midlength gas system and low profile gas block under a 10" to 12" rail.
1/7 twist barrel.

[USGILT]

So there is just a 3 oz difference between the two rails?

[bullseye]

i've been looking at the 410 ss upper myself. it says at the top of bravo's page this is a mid-length upper,,, a little farther down in the description of it,, it says carbine. which is it ,, mid or carbine???????

[USGILT]

I read the same thing as well. From the pictures on their website the distances from the FSB or low profile gas block look the same, like a carbine length with just a middy barrel.

USGILT

[IrishDevil]

The stainless barrels are mid-length gas. I bought a 16" SS BCM for 3 gun, I'm very happy with it. I bought the standard FSB upper, shaved the FSB down and installed a Troy 11" Extreme rail.

[CarlosDJackal]

For what intended purpose?

[USGILT]

IrishDevil

How do you like your SS barrel? Are you using a 1/8 twist? What type of ammo do you normally shoot and what type of accuracy to you get?

Thanks,

USGILT

[IrishDevil]

The BCM SS barrels are 1/8 twist. This is my first stainless barrel, I'm very happy with the accuracy so far. Using Prvi M193 which is not match ammo, I'm getting 1.5 MOA at 100 yards, it opens up to 2.25 MOA at 200. This is using a Meopta K-Dot 1-4, and a Gieselle SSA trigger. With Prvi 75 gr ammo groups range from .8 to 1 MOA at 100.

[USGILT]

Any reason you’re using M193 which is a 55gr projectile vs. M855 which is a 62 grain projectile? I thought 1/7 & 1/8 twist barrels were suppose to stabilize heavier gain projectiles better. Or does that just apply with 68 grain projectiles and up?

[IrishDevil]

It's just what I have on hand.

[USGILT]

Just curious! Thanks,