10-08-2015, 02:53 AM
I would look at your intended use first. The Grendel case is actually a very high efficiency shape when it comes to burning powder, so it does better than most cases that fit in the AR15, mainly because of being short and wide, with a 30 degree shoulder.
When you look at 10.5"-12.5" speeds, combined with the BC's, they do more than one would think.
If all I was doing was riding a bench or the prone, I wouldn't go more than a 22"-24". For carry guns, I like 18" or less. Across several barrels now, I don't really see a difference between my 16" and 18" with the speeds.
There's a velocity estimator chart in Volume I of the 6.5 Grendel Reloading Handbook series that shows the curve rate for change in barrel length, because it is not linear, so the typical thing you often hear is X fps per inch of barrel length, but that just doesn't hold true on the short (steep) or long end (flat) with any bottleneck rifle cartridge.
When you look at 10.5"-12.5" speeds, combined with the BC's, they do more than one would think.
If all I was doing was riding a bench or the prone, I wouldn't go more than a 22"-24". For carry guns, I like 18" or less. Across several barrels now, I don't really see a difference between my 16" and 18" with the speeds.
There's a velocity estimator chart in Volume I of the 6.5 Grendel Reloading Handbook series that shows the curve rate for change in barrel length, because it is not linear, so the typical thing you often hear is X fps per inch of barrel length, but that just doesn't hold true on the short (steep) or long end (flat) with any bottleneck rifle cartridge.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com