40S&W out of a 16" barrel? Kel Tec Sub Questions

[Dashunde]

I have a G27 & G35 and I'm giving thought to adding a .40 rifle, but only if it takes Glock mags and there is a ballistic advantage from the longer barrel.

Does .40 improve through 16 inches or is it actually slowing down again at the muzzle?

Does anyone besides Kel Tec make a short rifle in .40 that uses Glock mags?

[Theohazard]

I would assume the .40 would still be accelerating at 16", though at that point you'd probably be getting diminishing returns.

Check out www.ballisticsbytheinch.com, they have velocities of many loadings of most major calibers; they have a test platform where they cut the barrel down inch-by inch and measure the velocity each time. They also have test velocities of those loads from various real-world firearms. It's an awesome site.

[Steve_in_SEMich]

I chrono'd .40 through a Beretta PX4 pistol and their CX4 carbine - gained over 200fps. I'll look for the numbers. That was with the lighter bullet in the factory load. 155gr WWB I believe.

[rc]

You should see 1500fps with the 155 grain hollow points out of a carbine. You may only get an additional 100 to 150 fps with a more sedate 180 grain load. You can probably hit 1650 with a screamin 135 that does 1450 from a handgun.

[Jim Downey]

Yeah, we saw a gain of about 150 - 200 fps out of most loadings, going from handgun to carbine: http://www.ballisticsbytheinch.com/40sw.html

And the little Sub2000 is a lot of fun. I've got one in 9mm I've had for six or seven years, and I love it. The biggest advantage in going to the carbine isn't increased power, but a much more stable platform, making it very easy to be accurate out to 50 yards for most people.

Jim

[BillM]

Had a sub 2000 in 40. Fun little gun!

Other's in 40 that use Glock mags:

http://www.thureondefense.com/rifles

http://www.justrightcarbines.com/JR_..._Products.html

Olympic Arms makes the model K40-GL

[Dashunde]

I've been eyeing the KT as a all-purpose bag gun capable of hunting out to a hundred yards, if need be.
Since the ammo isn't ideal, an optic would be nice in order to extract all that it has to offer.

Aside from the KT being more stable and easier to master with a wee bit more fps its lacking any ability to mount a red dot or any sort of optic while still being able to fold completely.

I'm not sure it would be worth buying and hauling around - paying to have the G35's slide machined for a slick FastFire mount might be money better spent?

Too bad the KT doesn't fold sideways...

[wnycollector]

Here is some data I collected a few years ago from my .40 sub2K and my CZ-40B (4.4" barrel):
- Doubletap 155gr Gold Dot = 1247fps from the CZ and 1564fps from the Keltec;
- Doubletap 180gr Gold Dot = 1124fps from the CZ and 1400fps from the Keltac;
- Magtech 155gr JHP = 1136fps from the CZ and 1401fps from the Keltec.

[Dondor]

mec tech (sp) makes a carbine upper that uses a glock lower or 1911 lower.