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+--- Thread: the ARC vs the .243 WCF (/showthread.php?tid=527)
the ARC vs the .243 WCF - the_aught_6 - 01-07-2022
I know the 243 can't be chambered in an AR15, only AR10 ?
I don't have a load manual with the ARC loadings.... would someone give the ballistics for a 103 SST or a another varmint heavier bullet grain for both?
RE: the ARC vs the .243 WCF - grayfox - 01-07-2022
Hornady's load data for both AR style and bolt gun are online at hornady.com, and the latest 2022 hodgdon manual has 6Arc data in it.
6mmArc Saami specs are also available online, just as an fyi.
In the 6mm, Hornady's 103 bullet is an Eldx, for varmint style I would suggest the 95 SST (although billed as a cxp2 bullet), 87 Vmax, 75 Vmax, Berger 88 FB, Sie 80-85, then several Nosler's of 70 gr, 80 gr etc... even a few at 58-65 grs.
I shoot a few of these in my 6 Creed and 243, and am evaluating which one I would like to do in my 6Arc.
Cases based on the 308 (and 30 TC) are too long to fit into an AR15 frame, that's why they are done in an AR10 frame. Several 6mm cartridges are designed for the AR15 frame, in addition to the 6mm ARC. 6mm AR, 6x45, 6 PPC, 6 RAT, maybe a few others. One difficulty some cartridges have in either AR10 or -15 is the shoulder angle, an angle too slight makes for some feed problems, or so I've heard. I don't shoot any AR10's, I use bolt actions for that size of cartridge.
RE: the ARC vs the .243 WCF - the_aught_6 - 01-07-2022
Interesting !
Thank you for the info, and I'll check out online ballistics. I was just curious of the longer range retained energy of the 103's and the wind drift verses the lighter bullets ?
RE: the ARC vs the .243 WCF - grayfox - 01-07-2022
Now that's a good question, I wasn't sure where the first post was going...
The g1 ballistic coefficient for the 103 eldx is, iirc, 0.512. It does tend to retain KE better downrange, than a lighter bullet, which typically would have a lower BC.
Example, the 95 SST has a BC of 0.355, the 90 gr Sierra TGK (if you can find them) has 0.490.
I refer to the g1's b/c they are the ones most used in ballistics calculators, and are good for example out to, o, 500-600 yds.
In the case of comparing the 103 eldx to the 90 tgk, of course, retained energy also is affected by the lower mass of the 90 grainer.
Because of the 6Arc's small case capacity (small but mighty IMO) powder selection and actual MV's are somewhat constrained, but the original design for the military was for an AR-15 frame that could shoot 105-108 gr bullet out to 1000 yds with retained KE sufficient for long-range, light weight sniper purposes. So those high-BC bullets can definitely rock out to 1K.
Lots of ballistic apps available, couple of free ones are iStrelok, and PointBlank, but there are also others.
I do like the 103 in the 6 Arc by the way...