6.5 Grendel versus 223, 77gr SMK?

[photoracer]

You mean this? http://68forums.com/forums/showthread.php?29143-SSA-6-8SPC-140gr-VLD-Berger-Now-Available Looks like Nosler bought out SSA

Yes that was the round. I have yet to see any of that (Wikipedia says it is discontinued). I don't think it is still in their catalog. Biggest issue with B.C. in the 6.8 is the need for a longer bullet in a relatively short case. That is why the need for the PRI mags that allow a longer OAL so a longer bullet can be loaded longer without getting too far down in the case to affect case capacity and velocity. Right now the best B.C. available is the Sierra 135g MK HPBT with a BC of .488 (a very long 1.265" bullet). There are approximately 9 bullets available with BCs at or above .400. One is the 77g Elite SP at .400 (1.003") and the 105g GS Custom SP at .416 (1.230") is another if you want to use lighter bullets that can be loaded to higher velocities.

 

[justeric]

Any thoughts on the .243 WSSM for an AR-15? Looks like great ballistics.

 

[dist1646]

Any thoughts on the .243 WSSM for an AR-15? Looks like great ballistics.

The base of the case is too large work in an AR15. The AR15 platform is limited to smaller case sizes.
I would take a serious look at the 6mm HAGAR for a real ballistic advantage in the AR15 platform. It is still a handload only cartridge for now but, brass is available from Creedmoor Sports. The HAGAR shoots like a laser beam. Hornady submitted the HAGAR for SAAMI spec. and may eventually become a factory round if demand is there. Creedmoor shows the velocities for the HAGAR on their site. It is very easy to load for. Carl Bernosky has proven how well the HAGAR performs several times at the national championships.

 

[jimbobborg]

The base of the case is too large work in an AR15. The AR15 platform is limited to smaller case sizes.

Not quite. http://www.dtechuppers.com/ar-15-wssm-upper-receivers.html It does make standard AR mags into single-stack mags, though.

 

[atblis]

Seriuously, 6.5 Grendel is the answer you seek. It was designed from the get go to do exactly what it is you want. 243 WSSM is asking for trouble in an AR15.

 

[atblis]

The base of the case is too large work in an AR15. The AR15 platform is limited to smaller case sizes.
I would take a serious look at the 6mm HAGAR for a real ballistic advantage in the AR15 platform. It is still a handload only cartridge for now but, brass is available from Creedmoor Sports. The HAGAR shoots like a laser beam. Hornady submitted the HAGAR for SAAMI spec. and may eventually become a factory round if demand is there. Creedmoor shows the velocities for the HAGAR on their site. It is very easy to load for. Carl Bernosky has proven how well the HAGAR performs several times at the national championships.

Those velocities are for a 28" barrel and an OAL of 2.340".

 

[Lennyo3034]

I've had good luck with 77 TMKs out of my 20". I usually shoot the "low" node at 2740 fps. I also have a "high" node at 2830 fps that's marginally less accurate at 100 yards, but gain 90 fps of velocity.

My 20" Grendel barrel only pushed factory hornady 123 amax at 2450.

Using my "low" velocity numbers, I need 3.0 mils to get to 515 yards (del marva) whereas I needed 3.8 with factory Hornady 6.5 Grendel loads. At 500 yards, they were tied in regards to wind.

This was with the 77 grain Sierra TIPPED matchking, which has a significant BC advantage over the standard 77 SMK. These bullets are more jump sensitive than the SMKs and I have to load mine out to 2.310", which will not fit in a pmag. I use ASC SS mags which have worked flawlessly with cartridges at that length. If you were to switch to Grendel, then you'd have to do the same thing anyways.