We have talked about pistol-caliber carbines before. They are light, fun to shoot, more accurate than a handgun of the same caliber, and give your favorite cartridge a little extra velocity, too.
But how MUCH extra velocity? Lots of estimates get thrown around, but not a lot of hard #s. And how accurate are the factory specs, anyway?
Well here they are.
I started with .40S&W, since I had ready access to a pistol and carbine chambered for the round. 9mm is coming soon!
Since I had 5 different types of factory ammo, from 2 brands, I decided to test them all. As I get more ammo, I will test that too.
I tested using a Glock 23 (which has a 4″ barrel) and a Ruger PC4 (which has a 16.25″ barrel). I set up the chronograph, and put 10 rounds of a particular ammo through the pistol, then repeated the process (same ammo) with the carbine. I cleaned the chrony sensors with canned air between strings.
Here are the results, from heavy bullets to lighter ones:
That’s pretty close to Magtech’s factory spec, and since the test gun probably had a barrel longer than 4″, the lower velocity is understandable. (Magtech’s site did not specify what barrel length was used to test, nor whether it was an actual gun or a test barrel.)
That’s quite a decrease from factory spec, even allowing for a 4″ barrel. (Surprisingly, Federal did not supply barrel length or if it was a test barrel for any of their .40S&W factory ballistics). And that muzzle energy is barely above what Federal’s 9mm selections offer:
On to the next selection:
This was a serious deficit compared to the factory spec. It took the carbine-length barrel to approach the quoted ballistics! Yeah, it’s not a defensive round, but the fact that a major manufacturer is wrong on their #s is troubling. Maybe it was a bad batch? I haven’t seen any notice about it, and I actively look for such notices.
This is actually higher velocity & energy than the factory #s, and a longer barrel would be higher still. But, once again, the muzzle energy is only marginally better than Federal’s 9mm offerings (see above).
The lightest bullet of the bunch delivered the highest muzzle energy & velocity. It wasn’t as good as the factory specs (the shorter barrel is probably to blame for some of that). But this round offers the only significant upgrade from 9mm energy levels. And in the carbine, it offers much more.
But, on the subject of pistol caliber ammunition in carbines, the increase in velocity from the longer barrel was 114-156fps. That’s less than I would have guessed, and certainly less than the “200-250fps” that I have heard. Maybe these .40 rounds are really efficient?
I am troubled that 3 of the 4 Federal rounds were significantly lower velocity than quoted.
I have some Hornady ammo to test next, and I will get some others too. But for the moment, the 155gr HydraShok is going to be what I fill my pistol magazines with. I will use the others for the carbine.
Looks like the “light & fast bullet” proponents win this round.
After crunching the numbers, chronographing 5-round strings instead of 10-round strings offered nearly identical averages while costing less ammo
Tested Hornady’s TAP FPD 155gr ammo:
We have a new winner. Very consistent velocities in the pistol, too.