Comparison of 9mm rounds through pistol and carbine

[Phazer]

As promised, I finally had the chance to use my Magnetospeed V3 to speed test some rounds through a pistol with a 5-inch barrel (Taurus PT92) and a pistol caliber carbine with a 16-inch barrel.

Here's what I got:

Reloads 115gr through 5-inch barrel:
Shots: 6
Min 1067 Max 1114
Avg 1091 S-D 20 ES 47

Reloads 115gr through 16-inch carbine barrel:
Shots: 19
Min 1212 Max 1334
Avg 1255 S-D 26.2 ES 122

Speer Gold Dot 124g +p through 5-inch barrel:
Shots: 3
Min 1184 Max 1212
Avg 1200 S-D 14.7 ES 28

Speer Gold Dot 124g +p through 16-inch barrel:
Shots: 5
Min 1416 Max 1450
Avg 1437 S-D 14.1 ES 34

Looking at the numbers:

My 115gr reloads increased in average velocity from 1091 fps to 1255 fps. This represented a 15% increase in velocity by increasing the barrel length from 5-inches to 16-inches.

The 124g+p Speer Gold Dots increased in average velocity from 1200 fps to 1437 fps. This represented a 20% increase in velocity by increasing the barrel length from 5-inches to 16-inches.

Using the calculator here:
Beartooth Bullets > Ballistician's Corner > Foot-Pounds Energy

115gr reloads went from 304 ft-pounds energy to 402 ft-pounds energy

124gr+p Speer Gold Dots went from 397 ft-pounds energy to 569 ft-pounds energy.

I'll leave it to those who know more about a variety of loads to determine if a 9mm carbine with a 16-inch barrel is useful for defensive purposes. It sure is fun to play with at the range.

Cheers!

 

[Marine Cpl]

I think the powder used determines a lot on velocity increase. Your results mirror what I've seen online for reloads. Perhaps factory ammo uses a powder that is more conducive to a longer barrel?

Those 115's usually scream when using factory loads.

 

[Phazer]

Those 115's usually scream when using factory loads.

I was using a load that I'd worked up before I had my chrono. It was a recipe that cycled in all of my pistols. But...now that I've got the data, I know that I can push up my charge with a goal velocity of around 1200 fps through my 5" pistol barrel. I just didn't want to press my luck while I was "flying blind."

 

[Eddie Gunks]

Glock 34 and mpx

My 115 gr reloads were going like 1225 outta the glock and 1485 outta the mpx. Amazing gain.

I used the load data right off the titegroup can.

 

[RandallOfLegend]

There's 3 ways a cartridge can get "significant" extra speed from a longer barrel length
1.) More time in the barrel gives the expanding gas pressure extra time to accelerate the projectile
2.) Slower burning powders that don't completely burn in a short barrel will fully burn in the longer barrel, providing a higher pressure over longer amounts of time.
3.) The amount of powder in the cartridge can't completely burn over 3-5 inches will fully burn over 16-20 inches. Slightly different than the point above.

 

[togmaster]

What powder were you using in your reloads?

 

[gun_slinger_boy]

Fun having a way to measure your loads isn't it? What are you using to dispense your charges? Looks like the charge weights could be varying quite a bit. Out of the pistol the ES is very good but something is up out of the carbine. Were the reloads all out of the same batch? Were they all the same seating depth, case length, crimp, primer, powder etc?

 

[Celt]

That's a pretty good increase and performance. You're gaining a lot more power out of the 9 millimeter round through a carbine.

 

[Phazer]

What powder were you using in your reloads?

ETR-7 (by Expansion Industries)
115gr FMJ over 4.6 gr powder
OAL 1.12 inches

 

[Phazer]

Looks like the charge weights could be varying quite a bit.

Probably. I had been using a Lee autodisk powder measure. I've since changed to the Lee Auto drum which I think is more accurate and consistent. We'll see.

 

[gun_slinger_boy]

The autodrum is definitely more consistent. I just got done loading a bunch of 7.62x25 rounds for tomorrow. Unfortunately the autodrum still suffers with fine powders like the autodisk but it doesn't affect the load itself.

ETA: I chronied some test rounds earlier today and got 1400 fps out of the 4.5 inch barrel in the tokarev. This is a mid power round. Tomorrow I may chrony them out of the pps43 (10 inch barrel )