DUE FEB 2021 MONSTER 6mmARC Barrels

[NugginFutz]

Enough talk, already!

Awesome-Credit-Card.jpg

I have the entire rifle waiting in an AR-BuildBox. All it needs is a real barrel.

[Lemonaid]

Here is a data comparison between 6mm arc and 6ppc and 6.5 grendel.

6 arc-------------------------------6 ppc--------------------Difference---------------
Case length 1.490---------------1.5032------------------.0132 longer for ppc
Base to neck-1.2558------------1.2205------------------.0353 longer for arc
Base to shoulder 1.207---------1.0748------------------.1322 longer for arc
30 degree shoulder--------------30 degree shoulder---
Shoulder diameter-.4301-------.4299--------------------.0002 bigger for arc
Neck outside diameter .274----.2618--------------------.0122 bigger for arc
Neck length--.2342--------------.2827--------------------.0485 longer for ppc
Max coal 2.260-------------------2.1929 -----------------.0671 longer for arc
Neck base to max oal-1.0042----.9724-------------------.0318 longer for arc


6 arc--------------------------------6.5 grendel--------------Difference------------------
case lenth 1.490-------------------1.520--------------------.030 longer for grendel
Base to neck---1.2558------------1.280--------------------.0242 longer for grendel
base to shoulder 1.207------------1.1456--------------------.0164 longer for arc
30 degree shoulder-----------------30 degree shoulder----
Shoulder diameter-.4301----------.430----------------------.0001 bigger for arc
Neck O.D.---.274------------------.293-----------------------(.243 vs .264 )
neck length--.2342-----------------.235-----------------------.0008 longer for grendel
neck base to max oal-1.0042-----.980-----------------------.0242 longer for arc

The neck base to max oal is a key one, that is a general max bullet length before intruding into the case body.
If someone has case data for the 6mm AR, or other variants it would be great if you could post them here.

[grayfox]

IMO the spec that would make a difference to folks is the delta in case capacities.
Like between 6mmArc, 6 Ppc, 6mm-AR....

Case capacity translates to powder room. Especially from base to base of the neck (assuming the bullet basically takes up all the neck volume).

[A5BLASTER]

IMO the spec that would make a difference to folks is the delta in case capacities.
Like between 6mmArc, 6 Ppc, 6mm-AR....

Case capacity translates to powder room. Especially from base to base of the neck (assuming the bullet basically takes up all the neck volume).

Bout 4 tenths of a grain.

[grayfox]

BFT, what can you tell us about some of the barrels coming out, some have standard gas tube lengths (mid, rifle, etc) while others are using a rifle+1... for 18" and up. One mfr has a 21" barrel and rifle+1.
Others, like faxon and BA seem to be offering regular gas lengths.
Has anyone been discussing why the differences?

[am4966]

BFT, what can you tell us about some of the barrels coming out, some have standard gas tube lengths (mid, rifle, etc) while others are using a rifle+1... for 18" and up. One mfr has a 21" barrel and rifle+1.
Others, like faxon and BA seem to be offering regular gas lengths.
Has anyone been discussing why the differences?

[Popeye212]

Mark here is the Saami drawing.

[BluntForceTrauma]

BFT, what can you tell us about some of the barrels coming out, some have standard gas tube lengths (mid, rifle, etc) while others are using a rifle+1... for 18" and up. One mfr has a 21" barrel and rifle+1. Others, like faxon and BA seem to be offering regular gas lengths. Has anyone been discussing why the differences?

[rabiddawg]

[m796rider]

Up to a certain point, I agree.

However, JSOC can buy pretty much whatever they want, as witnessed by the Hk416s, MP7s, suppressors, wide FOV NODs, Mk48s, and who the heck knows what else that shows up in photos full of redacted faces.

[FRB6.5]

The guesses on longer gas lengths would be: 1. experience from the Mk12 SPR, rifle length gas on an 18" made for very low recoil and increased accuracy and sight picture (and less part wear). 2. Expected suppressor use.

[BluntForceTrauma]

For the 18", specifically, I don't consider using a standard rifle length tube to be exotic. I think it makes sense and that's what I use on my 65G 18s, and that's what I'll use on any 6mmARC 18s.

I'm referring to these Rifle + 1 tubes, and such.

[StoneHendge]

Why? We've got a huge database of knowledge from all the 6mm Grendel wildcats, and none of them NEEDED any special gas-tube lengths..

My 18" 243 LBC with MLGS is a rebarreled 6.5 Grendel with MLGS with an AGB. Only change was barrel, compensator and bolt. No real timing issues with 123s at 2450 as 6.5mm. Definately timing issues with 95s at 2750 as 6mm. 108s will have more dwell time. Just a piece of apples to apples info.

[82HALO]

Ok, I need one...no maybe 2 of these barrels as soon as possible! Talking to my son in law his brother is a hornady rep and I can get my hands on some ammo in possibly a week and a case in 3 or 4 weeks!

[BluntForceTrauma]

My 18" 243 LBC with MLGS is a rebarreled 6.5 Grendel with MLGS with an AGB. Only change was barrel, compensator and bolt. No real timing issues with 123s at 2450 as 6.5mm. Definately timing issues with 95s at 2750 as 6mm. 108s will have more dwell time. Just a piece of apples to apples info.

Good info. You happen to know the gas port size on your 243 LBC?