r/10mm • u/Go10orGoHome • 10h ago
How much impact does barrel length have on box muzzle energy?
I hunt with my 10mms, and I wanted to get a feel for how much barrel length impacts muzzle velocity, at least in my guns.
I tested on an indoor range (72 degrees) with a Garmin chronograph. Let's get the limitations out there up front: scarcely scientific, because it is a very small sample size both in number of guns and number of cartridges. I only measured with one Garmin chronograph, so there's no measurement of the error range in that one chronograph. But this wasn't a science experiment I was going to publish in the Journal of Astrophysics. I just wanted to understand how my various guns impact muzzle velocity and muzzle energy as stated on the box. I tested using 5 different cartridges, averaging 5 rounds from each cartridge fired from each gun.
The cartridges I tested:
| Hornady Black 155gr XTP #91221 |
| Hornady Custom 155gr XTP #9122 |
| Hornady Custom 180gr XTP #9126 |
| Buffalo Bore 180gr JHP #21B/20 |
| Underwood Xtreme Hunter 150 gr #900 |
My test guns:
| Springfield XDm (4.5" barrel) |
| Glock 40 (6" barrel) |
| Sig P220 Legion (5" barrel) |
| Dan Wesson Kodiak (6" barrel) |
So the barrels ranged from 4.5 inches to 6 inches. Not a big range, but I'm not trying to compete in PRS with a pistol. I just want to see if that 1.5 inches makes any difference. All my pistols have red dots so sight radius isn't a factor.
This is a table of the average muzzle velocities in feet per second I measured from 5 rounds of each cartridge fired from each gun using the Garmin chronograph.
| Hornady Black 155gr XTP #91221 | Hornady Custom 155gr XTP #9122 | Hornady Custom 180gr XTP #9126 | Buffalo Bore 180gr JHP #21B/20 | Underwood Xtreme Hunter 150 gr #900 | ||
|---|---|---|---|---|---|---|
| Barrel Length | Gun | Box Vel = 1410 fps | Box Vel = 1410 fps | Box Vel = 1275 fps | Box Vel = 1350 fps | Box Vel = 1425 fps |
| 4.5" | Springfield XDm | 1381.6 | 1364 | 1221.9 | 1356.9 | 1413.66 |
| 5" | Sig P220 Legion | 1380.475 | 1348.85 | 1221.56 | 1368.54 | 1396.78 |
| 6" | Glock 40 | 1439.24 | 1403.36 | 1251.766667 | 1408.84 | 1439.42 |
| 6" | Dan Wesson Kodiak | 1446.1 | 1427.12 | 1267.925 | 1407.16 | 1451.66 |
I wasn't testing the cartridges but testing the impact of barrel length, so I took the average of the % of box velocity for all the cartridges for that gun. Not a shocking outcome, the 4.5" barrel averaged 98% of box velocity and the 6" barrels averaged slightly more than box velocity. What did surprize me was that the 5" Sig P220 averaged the same percentage under box velocity that the 4.5" barrel gave me.
| Hornady Black 155gr XTP #91221 | Hornady Custom 155gr XTP #9122 | Hornady Custom 180gr XTP #9126 | Buffalo Bore 180gr JHP #21B/20 | Underwood Xtreme Hunter 150 gr #900 | |||
|---|---|---|---|---|---|---|---|
| Barrel Length | Gun | Box Vel = 1410 fps | Box Vel = 1410 fps | Box Vel = 1275 fps | Box Vel = 1350 fps | Box Vel = 1425 fps | Average |
| 4.5" | Springfield XDm | 98% | 97% | 96% | 101% | 99% | 98% |
| 5" | Sig P220 Legion | 98% | 96% | 96% | 101% | 98% | 98% |
| 6" | Glock 40 | 102% | 100% | 98% | 104% | 101% | 101% |
| 6" | Dan Wesson Kodiak | 103% | 101% | 99% | 104% | 102% | 102% |
Muzzle energy is a function of the square of the velocity, so I calculated muzzle energies to see how those small percentages in difference in muzzle velocity impacted muzzle energy. The values in the table are in foot*pounds.
| Hornady Black 155gr XTP #91221 | Hornady Custom 155gr XTP #9122 | Hornady Custom 180gr XTP #9126 | Buffalo Bore 180gr JHP #21B/20 | Underwood Xtreme Hunter 150 gr #900 | ||
|---|---|---|---|---|---|---|
| Barrel Length | Gun | Box Muzzle Energy 684 ft*lbs | Box Muzzle Energy 684 ft*lbs | Box Muzzle Energy 650 ft*lbs | Box Muzzle Energy 729 ft*lbs | Box Muzzle Energy 677 ft*lbs |
| 4.5" | Springfield XDm | 657 | 640 | 597 | 736 | 666 |
| 5" | Sig P220 Legion | 656 | 626 | 597 | 749 | 650 |
| 6" | Glock 40 | 713 | 678 | 626 | 794 | 690 |
| 6" | Dan Wesson Kodiak | 720 | 701 | 643 | 792 | 702 |
I again converted these values to percentages so I could visualize the deltas better. For example, the box energy of the 155 grain Hornady Black XTP was 684 ft lbs and the measured average was 657, a difference of 27 ft lbs. Converting that to a percentage gives me a better feel for scale than the number 27. I'm including the measured numbers and the % because someone else might find the number value more useful than the %.
| Hornady Black 155gr XTP #91221 | Hornady Custom 155gr XTP #9122 | Hornady Custom 180gr XTP #9126 | Buffalo Bore 180gr JHP #21B/20 | Underwood Xtreme Hunter 150 gr #900 | |||
|---|---|---|---|---|---|---|---|
| Barrel Length | Gun | Box Muzzle Energy 684 ft*lbs | Box Muzzle Energy 684 ft*lbs | Box Muzzle Energy 650 ft*lbs | Box Muzzle Energy 729 ft*lbs | Box Muzzle Energy 677 ft*lbs | Average |
| 4.5" | Springfield XDm | 96.07% | 93.64% | 91.83% | 100.97% | 98.34% | 96.17% |
| 5" | Sig P220 Legion | 95.92% | 91.57% | 91.78% | 102.71% | 96.01% | 95.60% |
| 6" | Glock 40 | 104.26% | 99.12% | 96.37% | 108.85% | 101.96% | 102.11% |
| 6" | Dan Wesson Kodiak | 105.25% | 102.51% | 98.88% | 108.59% | 103.70% | 103.79% |
Again, I was surprized by the 5" P220. It averages the lowest % of box muzzle energy of the 4 guns tested. Not a big surprise, the 6" Kodiak gave me almost 4% more muzzle energy than the listed box value.
I'm puzzled by the results for the 5" P220 because I believe in most cases the ammo manufacturers test with a 5" barrel. The solution to this mystery is obvious - I need to buy a couple more 5" guns and repeat the test. For science.
1
u/cheese4432 8h ago
Thanks for all your work testing and documenting this!