38 Special Ammo Power Factor Guide
How consistent is 38 Special ammo?
One of the biggest struggles if you want to shoot revolvers in competition is finding ammo that makes power factor. What’s power factor? It’s a way that the shooting sports measure the energy of a projectile. It’s a simple formula, it’s bullet weight times velocity, and then divide by 1000 to make a three digit number with some decimals. So for example, a 158gr projectile at 850 FPS would have a power factor (PF) of 134.3.
This matters because in USPSA you need to make what’s called “minor” power factor if you’re shooting an 8 shot revolver. That’s 125. In CMP Action Pistol and ICORE, you need to make 120, and in IDPA Revolver if you’re shooting a speed loader gun it’s 105. This can present a problem because not all factory ammo makes those power factors.
The Ammo Used
Now, if I didn’t test fire your favorite off the shelf load, I’m sorry. I test fired a repressive sample of what I consider to be high quality ammo that’s easily commercially available and would be rounds I’d consider for competition. The test platform for these was my USPSA revolver, a Taurus USA 608 Competition in 357 Magnum using moonclips.
Test protocol was simple. Fire 5 shots for record over my Garmin chronograph.
American Quality Ammunition 158gr FMJ - I knew absolutely nothing about this brand, I had never heard of it before it popped up on Lucky Gunner. Because I’m always looking for ammo that makes PF, I ordered 250 rounds. 5 test rounds had an average muzzle velocity of about 879 FPS, which gives us a power factor of 139. That easily makes minor and is good to go for every shooting sport. Their stated velocity on the box is 850 fps.
Federal American Eagle 158gr LRN - This has been my primary ammo for IDPA for ages. It’s accurate and consistent, with the only real drawback being how dirty/smokey it is when you shoot it. Fouling and leading is a problem here. It had an average velocity of 789.8 FPS, for a power factor of 124.8. That’s no-go for USPSA, but good for everything else. The stated velocity on the box is 770 FPS.
PMC 132gr FMJ - I’ll be brief on this, I really wanted this be a viable option for lightweight FMJ, but the power factor on this was 118.8, which means it would only be good for IDPA, and in my opinion the Federal 130gr FMJ is a lot more consistent.
Hornady Critical Defense 110gr +P - Fun fact, this load nearly perfectly duplicates the old “Treasury Load,” pushing a 110gr bullet to nearly 1100 FPS. Our average velocity here was 1083, giving us a power factor of 119.14. That would only be good for IDPA, and at over a buck a round I don’t think I’d want to spend that money. That being said, it is crazy accurate, and has very minimal felt recoil.
Hornady Custom 158rd XTP/JHP - I really wanted this to make minor PF for USPSA. The XTP is a fantastic bullet for competition shooting due to its inherent accuracy. Unfortunately, I was only able to get an average MV of 776.6 out of this, for a PF of 122.7. That would make it acceptable for ICORE and Bianchi Cup.
Remington Performance Wheelgun 158gr LRN - I really like this stuff. I’ve shot a ton of it and it shoots great. It’s like a cleaner version of the Federal 158gr LRN but with a better bullet profile for speed loading. The box says these are making 755 FPS, and out of my six inch test gun I got an average velocity of 790 FPS, which is better than the box. Final PF is 124.9, which isn’t good for USPSA but gets you there for IDPA, ICORE, and Bianchi Cup.
Federal American Eagle 130gr FMJ - This is my go-to for FMJ practice ammo. Fun fact about this load, it is nearly identical in terms of pressure and ballistics to the old USAF duty load. My average velocity was 863, for a PF of 112.2. This would be an IDPA/Practice only load based on that, but it reloads super fast thanks to the bullet profile.
Federal 158gr +P LSWCHP - This is Federal’s current production version of the FBI load. To be clear, not a gaming load, but a personal defense load. This easily cleared power factor, coming in at 149.2, which means the average muzzle velocity was around 940 FPS. I have and do carry this load in 4 inch service sized revolvers, but for games it’s a little too punchy.
Caleb’s Choices
Alright, so here’s what I’d pick for each game. I do want to note as well that ICORE has an “approved ammo” list, where so long as you’re shooting ammo that’s on their list, you don’t need to meet power factor. I’m working with CMP to get one of those for their revolvers as well.
IDPA: My choice would be the Federal American Eagle 130gr FMJ. Since the IDPA PF for speed loader fed guns is 105, this load still clears that by a handy margin, and again as I’ve noted tends to be very fast into the gun thanks to its bullet profile. This of course assumes that my gun either has adjustable sights or hits to the sights with this load.
USPSA: Of the loads on this list the only one that’s actually viable is the American Quality Ammo load, coming in a 139 PF. The problem is that I have trust issues with small manufacturers and their ability to turn out a consist product. I’d actually be more likely to run the Remington Performance WheelGun 158gr LRN, and just sort of pray that when I get to chrono that I get a couple of bullets at 795 FPS and squeak across the line that way.
ICORE: Remington Performance WheelGun all the way.
Action Pistol/Bianchi Cup: Again, of the loads on this list I’d probably go with the Hornady XTP 158gr, just because of how accurate the XTP bullet can be. Plus, I prefer a jacketed bullet for Bianchi Cup, since shooting through a cloud of lead dust and smoke makes things a bit more difficult.
Steel Challenge: do whatever you want, there’s no PF in Steel Challenge. I run 148gr wadcutters because they have no recoil.
Now as we close this article I’m sure you’re thinking “why not just handload” and you’re 100% right. That would be a guaranteed way to make sure all my ammo makes power factor, and that’s what a lot of serious revo shooters do. That’s not who this list is for. This list is for people who want to compete with a revolver but don’t have the time to invest in hand loading.
Or, I suppose I could just sack up and shoot 357 Magnum.