6mm ARC vs 6mm Creedmoor Shorty?

texjitter

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Having a chat with a buddy the other day who insisted that a 16" 6mm ARC would outperform a 16" 6mm Creedmoor using the same bullet... (both in bolt guns)

Can somebody else help explain this? My "buddy" is an avid reloader and gun nut, but on paper when I crunch numbers the creedmoor would still outperform the arc by quite a bit based on factory Hornady 108 Eld-M ammo

I currently have a 26" 6 creed barrel but would like to spin on another in 16 or 18" to be a little handier for Texas deer/hog hunting
 
Your buddy has no idea what he's talking about. You can push a 6mm arc a little harder than the factory offerings in a bolt gun, and in fact, the hornady reloading manual has two separate sections for loading the 6mm arc, (gas gun/bolt gun) based on maximum pressures of 55k, and 63k, (if my memory serves), but even at the 63k, it lags well behind the 6mm creedmoor. The powder capacity isn't even close.
 
As far as I know I the 6 CM has much more case capacity and higher operating pressures so I'd expect more velocity especially with longer barrels. Now if one pushed the 6mm ARC to say 58k psi then who knows. My best guess I'd say a 6mm CM out of a 18" barrel would push a 108 ELDM around 2850 fps. My buddy claims 2750 fps out of his 18" gas gun 108 ELDM. So an 6mm ARC @58k psi might get there.
 
I get like 2550fps from my 18" 6mm arc ar15 shooting factory 108gr eld-m.
I just just spoke to him yesterday and that's what he said he was getting with factory out of his 14.5 suppressed. We do deal with a lot of different cartridges and firearms so either he or I could be getting the numbers mixed up.
 
I just just spoke to him yesterday and that's what he said he was getting with factory out of his 14.5 suppressed. We do deal with a lot of different cartridges and firearms so either he or I could be getting the numbers mixed up.
I'm not disputing his numbers, because no 2 guns are the same, and he may be using his own loads where I'm shooting factory ammo. I only get 2680fps out of my 22" barrel. I shot a prs match with that setup back in September.
 
I'm not disputing his numbers, because no 2 guns are the same, and he may be using his own loads where I'm shooting factory ammo. I only get 2680fps out of my 22" barrel. I shot a prs match with that setup back in September.
I'm not disputing your numbers either. I'd rather see consistent actual data. Otherwise none of us benefits
 
The only way that works is if his arc barrel is very fast and the creed is super slow and loaded light, similar pressures the creed will outperform the arc every time now the arc will be more efficient
 
The 6mm ARC was designed to match specific DOD requirements while fitting in the AR15 platform. Which it does pretty well within those limitations. Comparing 6mm ARC to 6mm CR is is apples and oranges again. You can boost the performance of the 6mm ARC in a bolt action quite easily.
 
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