07-12-2017, 12:57 PM
(This post was last modified: 07-12-2017, 01:28 PM by Chrazy-Chris.)
js8588 Wrote:I know I'm new here and I hate to be "that guy" but please, don't do that. Don't use a barrel that's going to ballistically handicap a great round. The shortest I would (will) go on a Grendel is 18 inches. I feel the same about my 556s too. Even 16 seems too short. Then again, I'm 6'2 and 205lbs. Longer barrels fit me fine.
I've done a LOT of research into this (mostly because I really don't need to drop money on another rifle at this point in my life so the next best thing I can do is go full nerd on the research for one) and I went through the following steps to choose this setup:
-I have several AR's but none of them are very comfortable to carry with my suppressor - a 9" 24oz tank of a suppressor. 14 or 14.5" is as short as I want to go w/ pinned FH (don't want to do paperwork or carry a "pistol" for hunting).
-I don't have the money to build an AR-10 and an added plus, I can use an AR-15 lower I already have built with a nicely broken-in SSA and nice stock/grip/enhanced buffer spring... Must -be a cartridge that fits in a standard AR-15.
-I want the ability to kill deer with it @400yrds. I used ft-lbs of energy and considered velocities required to expand hunting rounds. The max range I would take on a deer is 400yrds.
With these parameters, I calculated the ballistics data for several different loads with recorded 14.5" barrel velocities from 5.56, 300blk, 7.62x39, 6.8SPC, and 6.5 Grendel. The Grendel beat out all the other cartridges @400yrds with the most energy on target while still having the required velocity to expand the bullet on impact. An added plus was the lower wind drift.
The Grendel was the clear choice for me to build in this setup. Additionally, I already have a 20" Grendel I use for shooting steal out to 1k. Box checked. With my suppressor, a 14" barrel turns into a (heavy) 23" barrel. I'm 6'2" 185lbs and consider myself to be in great shape. Carrying a 20" barrel plus suppressor is still just too unwieldy for spot and stalk. I spent the money for this can and I want to use it in a platform that I actually carry, rather than just on pistol range toys or benchrest guns. Finally, this is America and I can do what I want (within the letter of the law).
ETA: For factory 123SST with advertised 2350fps MV from 16" barrel (described above from Kmon as a pinned 14.5") @3000' Elevation (my hunting grounds):
@400yrds- Velocity: 1804fps; Energy: 889ft lbs, Holdover: 3.0mils, 10mph wind drift: .9mils
For comparison's sake- with the 18" you'd recommend, figuring a MV of 2435fps (extrapolated the difference in advertised MV between 14.5" and 24" for a loss of 24fps/in):
@400yrds- Velocity: 1877fps; Energy: 962ft lbs, Holdover: 2.7mils, 10mph wind drift: .8mils
I don't think Mr. Mule Deer will know the difference but I sure will when carrying the gun up and down the canyons.