help me decide on a cartridge to use in AR15 clone
07-04-2021, 02:30 PM
#1
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Thread Starter
Join Date: Dec 2017
Location: texas
Posts: 1,201
help me decide on a cartridge to use in AR15 clone
Im trying to decide on a cartridge to use in a AR15 based ,rifle build
this will have a 16"-20 HEAVY STAINLESS BARREL
heres the basic requirements as far as I see them,
the rifle must retain use of and work with the original mil spec magazines
or magazines that are very easy to modify from GI
AND use of as many mil spec parts as possible, as this is a big plus
,in keeping cost and conversion lower,
cases must be reasonably easy to find
it must be at least 24 caliber but not more than 30 caliber
the cartridge must be able to provide more power than a 223 at 400 yards
so far I see the cartridges below as contenders
with the 223 case necked up to 24 or 25 , or 30 caliber looking like the better options
6mm/45 cartridge
25/45 sharps cartridge
6.5mm grendel cartridge
6.8 SPC, cartridge
300 black-out
this will have a 16"-20 HEAVY STAINLESS BARREL
heres the basic requirements as far as I see them,
the rifle must retain use of and work with the original mil spec magazines
or magazines that are very easy to modify from GI
AND use of as many mil spec parts as possible, as this is a big plus
,in keeping cost and conversion lower,
cases must be reasonably easy to find
it must be at least 24 caliber but not more than 30 caliber
the cartridge must be able to provide more power than a 223 at 400 yards
so far I see the cartridges below as contenders
with the 223 case necked up to 24 or 25 , or 30 caliber looking like the better options
6mm/45 cartridge
25/45 sharps cartridge
6.5mm grendel cartridge
6.8 SPC, cartridge
300 black-out
Last edited by hardcastonly; 07-04-2021 at 02:42 PM.
07-05-2021, 03:23 PM
#3
Nontypical Buck
Join Date: Oct 2009
Location: Kansas
Posts: 3,905
The 6.5 Grendel and 6.8 SPC do not use stanag magazines nor standard AR-15 bolt heads. Both use different magazines and bolt faces, and of course, barrels, while everything else about the rifle can be standard/Mil-spec. But these two, plus the 6mm ARC are the best options for getting the most out of the AR-15 frame.
Personally, I rank the 3 as 6 ARC, 6.5 Grendel, then 6.8 SPC a long ways behind the other two. The SPC used to be my front runner, but the market shifted significantly about a decade ago now, and support for the SPC has waned considerably while the Grendel components have flourished. Pointing out the ARC uses the Grendel bolt face and magazines.
The 6x45 and the 25-45 Sharps are fine cartridges, but lack the case capacity to really handle the heavier bullets to make things happen downrange compared to these larger cases.
Personally, I rank the 3 as 6 ARC, 6.5 Grendel, then 6.8 SPC a long ways behind the other two. The SPC used to be my front runner, but the market shifted significantly about a decade ago now, and support for the SPC has waned considerably while the Grendel components have flourished. Pointing out the ARC uses the Grendel bolt face and magazines.
The 6x45 and the 25-45 Sharps are fine cartridges, but lack the case capacity to really handle the heavier bullets to make things happen downrange compared to these larger cases.
