I brought up the topic of the practical value of 9mm in an SBR when what I believe to be more effective calibers are available. I didn't want to sidetrack the other thread, but thought the topic had merit, and wanted to address some observations that were made.
As for crunching the numbers, assuming an initial muzzle velocity of 1050fps and using the best 9mm BC I could find and a poor (the best I found was .62).308 BC:
147gn 9mm HP, .21 BC
Distance(YDS) Velocity KE
0 1050 360
25 1021 340
50 996 324
75 973 309
100 951 296
220gn .308 OTM, .55 BC
Distance(YDS) Velocity KE
0 1050 539
25 1039 527
75 1028 516
100 1008 496
I could spend the time and effort to get momentum and Taylor numbers as well, but it wouldn't change the outcome.
I don't have any interest (even assuming I was a Glock guy) in 33 round pistol magazines or 15-17 round rifle magazines, so the interchangeability is of little to no value to me, and I'd say the bulk of shooters I know. Interchangeability of magazines between pistol and rifle is not even a consideration when choosing a weapon. Commonality and availability of other parts- bolts/carriers, buffers, recoil springs, and standard magazines are of much greater value. Additionally, in the little I've looked into it, the Glock pattern lowers aren't particularly popular- most building 9mm ARs seem to choose the Colt pattern.
One thing I do know: Short, suppressed ARs in 300BLK are being operationally used by JSOC elements, even while they're still being experimented with, developed and improved upon. Nobody's taking a 9mm AR downrange, nor are they even experimenting with or considering them...
My original question was what, if any, practical value a 9mm had over a .300in an SBR. For me, the answer is no. Both suppress equally well, .300 offers vastly superior terminal ballistics and has a much greater effective range across the spectrum of common loadings. 9mm is much less expensive to shoot, and (barring a panic) ammunition is much easier to find on the shelf. Particularly if you handload, the .300BLK is much more versatile.
The segment bolded in black it true, with the exception of a Nosler product specifically designed for subsonic use that expands to 3x its original size at as low as 700fps. The segment highlighted in red is NOT true. While 220gn 308 HP or OTM bullets don't expand well at subsonic velocities, they DO tumble, yaw and fragment, leaving wound channels that put the best 9mm HPs on the market to shame.
As for crunching the numbers, assuming an initial muzzle velocity of 1050fps and using the best 9mm BC I could find and a poor (the best I found was .62).308 BC:
147gn 9mm HP, .21 BC
Distance(YDS) Velocity KE
0 1050 360
25 1021 340
50 996 324
75 973 309
100 951 296
220gn .308 OTM, .55 BC
Distance(YDS) Velocity KE
0 1050 539
25 1039 527
75 1028 516
100 1008 496
I could spend the time and effort to get momentum and Taylor numbers as well, but it wouldn't change the outcome.
I don't have any interest (even assuming I was a Glock guy) in 33 round pistol magazines or 15-17 round rifle magazines, so the interchangeability is of little to no value to me, and I'd say the bulk of shooters I know. Interchangeability of magazines between pistol and rifle is not even a consideration when choosing a weapon. Commonality and availability of other parts- bolts/carriers, buffers, recoil springs, and standard magazines are of much greater value. Additionally, in the little I've looked into it, the Glock pattern lowers aren't particularly popular- most building 9mm ARs seem to choose the Colt pattern.
One thing I do know: Short, suppressed ARs in 300BLK are being operationally used by JSOC elements, even while they're still being experimented with, developed and improved upon. Nobody's taking a 9mm AR downrange, nor are they even experimenting with or considering them...
My original question was what, if any, practical value a 9mm had over a .300in an SBR. For me, the answer is no. Both suppress equally well, .300 offers vastly superior terminal ballistics and has a much greater effective range across the spectrum of common loadings. 9mm is much less expensive to shoot, and (barring a panic) ammunition is much easier to find on the shelf. Particularly if you handload, the .300BLK is much more versatile.