Power factor and recoil

Does power factor translate into recoil, all else being equal? What about 2 rounds having same PF, but one has a 115gr bullet compared to one with a 124gr bullet. Still same due to same PF or would one have more perceived recoil based on bullet weight?

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I’m thinking the 124 kicks more.

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In USPSA matches 9mm is considered minor power factor. 40& 45acp are major power factor. If 115 &124 gr 9mm have the same power factor it would be that the 124 was loaded to a slower velocity.
Same power factor should have the same recoil.

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In 308 out of the same rifle 180 gr from the same manufacturer will not recoil the same as a i50 gr. The same for the 40 S&W.

I don’t know about power factor, or whether or not it translates into recoil lbs.

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I ask because there was a discussion on another forum about factory ammo choice for GSSF competitions (there is no power factor minimum requirement). A lot of people were saying their choice was 147 or other higher grain bullet choices. It didn’t make sense to me as a 115gr bullet with a MV of 1120fps has a lower PF than a 147gr bullet at 925fps. Thats a PF of roughly 129 vs 136. If PF equals recoil, it makes no sense to me why someone would prefer a higher recoil, even if only slightly higher.

I don’t know, it’s just something that got me thinking. I always assumed that a lower power factor meant lower recoil and that was why some orgs like IDPA and USPSA had a minimum PF requirement so that there was some sort of competitive standardization. GSSF, with no PF requirements, definitely gives an advantage to reloaders as they can load as low as they want while still reliably cycling the pistol. That’s a different topic altogether and has been discussed as well.

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Well, yes and no. Load a 115 to a higher velocity but the same PF as a 160 for instance and the recoil will be far more noticeable. I used to load 160s to a just above legal PF and the recoil was extremely soft, not at all like the 115s loaded to the same PF. The recoil will be the same loaded to the same PF as measured by an instrument, but it’ll feel different in the hand. Now on pepper poppers they don’t act the same either. The heavy bullet has lots more momentum and really knocks steel down.

As far as 9mms being minor PF, again yes and no. Most are. But one shooter loaded his to major PF. He didn’t get many loads from his brass. Those 160s I loaded? Every once in awhile they’d give me a malfunction in my PCC. They were made for a handgun and worked 100% in that. Anyway, I got tired of the random malfunctions and just loaded a safe load that functioned 100% in the PCC. I didn’t chono them until I got home from a match and was surprised to see that they were within a hair of being major PF. :smile: I didn’t have any malfunctions that match and the RO asked me if I changed the load I was shooting. :grin:

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It does make a “Back on target” difference, seems to me equal PF the lighter bullet traveling faster has less muzzle rise.

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Loading heavy and light bullets in bigger revolvers I feel like I can speak to this.
A 240 gr for instance will require more powder to get it moving at the velocity of a 300 grain bullet. The larger the bullet the more mass it has and that mass will determine the amount of recoil. When I load larger bullets even though they may be slower than a smaller bullet the felt recoil of the larger bullet is definitely more and the down range power is greater . Once the larger mass is moving it is harder to slow it down.

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Y’all are reinforcing my thoughts on the matter. I’ve purchased a case of 115gr 9mm and 200gr .45 from Freedom Munitions because they had the lowest power factor of factory ammo that I could find in those calibers with a reasonable price. The “back on target” speed that Al mentioned is important to me. I cannot outshoot my ammo at this point, but I want to work in that direction. I’m working on speed of buzzer to 2nd shot on target currently.

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It all has to do with the energy out the muzzle in the form of PF. That’s what PF is, energy out the muzzle (or a few feet away) measured in a specific way (mathematically). If the PFs aren’t equal or close you’re comparing apples to oranges. I have no idea if ft/lbs has any equivalence in PF (I doubt it). Without doing the math to get the PF anything felt is meaningless.

Stan, no you really can’t speak to it since it’s a competition thread and not a maximum effort cartridge thread. Sorry to be blunt but that’s just the way it is. It’s apples to oranges. What are the PFs of the loads you reference? Clearly they make major, so what is the PF? Yeah, figure it out and it’ll be overkill for competition and no one in their right mind would ever use them competitively where one just needs to make their PF reliably and have no more than what’s needed to play the game. The PFs need to be quite close to the same for each load. Not knowing that it’s apples to oranges.

Yeah, I can load maximum effort loads in big calibers too and yes the heavy bullets will always have more recoil. That’s a duhhhh! But that’s not the question posed in the thread.

Preyhunter, trust me on this, I played the PF game for years. A fast light bullet gives a fast sharp recoil and muzzle flip, a slow bullet still cycles the slide (same energy) but with the same PF the recoil is spread out over time and feels like a gentle shove. Did it for years. Yes, 1200 fps feels substantially different than 800 fps out the muzzle. I used to call them my butterfly fart loads. One gent would tell me they sounded like a .22. But they still made minor PF. Note that all velocity numbers above are for illustration, close but not precise. My memory sux.

If you reload and can chrono your loads (that’s mandatory for PF, there’s no way around it) experience it for yourself.

Here’s my butterfly fart load data for my 5" M&P:

160 grain bullets
782 fps = 125 pf
790 fps = 126 pf
800 fps = 128 pf

3/9/16
160 gr Coated Bayou Bullet
1.158" LOA
3.2gr Power Pistol
800 fps.
PF 128

The bullets were cast for .38 but I had them sized for 9mm. Reject rate due to the internals of the brass run about 20%. (Yeah, I hated that!) I case gauged my ammo and that’s what bullet pullers are made for. Since I used range brass sorting cases would have been largely futile IMO. Yeah, glad I no longer need to play the butterfly fart load game
with the PCC.

edit #2: my memory for the load data is better than I thought it would be!

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So, PF being equal you would go with the heavier bullet, otherwise go with the lower PF like the example?

I’m not a reloader so I can’t play that game. I have to go with what I can buy premade. I imagine I could find a custom loader that I could buy from, but then price becomes an issue.

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Buy a box of each and decide what YOU like. The recoil feel will be different and I can’t tell you what you’ll like best. I can tell you what I liked best, that’s all. Very few folks locally (maybe none now?) played the butterfly fart load game. I had some shooters ask to try my loads and I had to explain to them that they might not cycle their gun(s) (not enough energy for my PCC either 100%) and they’d almost certainly hit to a wildly different POA.

I really can’t address factory ammo since I shoot so little of it so infrequently. I make my ammo to do what I want it to do. It’s not a cop out, it’s the truth and I won’t BS you unless you ask me to produce some fiction.

If you’re shooting competitively do you get the USPSA magazine? It comes monthly or in an email weekly bit by bit. I’d need to look, but there are maybe 2 big commercial manufacturers of competition ammo that make the PF cut offs automatically and advertise in it. If you aren’t a USPSA member give me time and a PM to check who they are. I have no idea what they offer or pricing. I bet it’s competitive, but I really don’t know, that would be up to you to check. Let me know if you need me to find the manufacturers and send or post what I find, hopefully links. I never did it so I have no idea what I or you will find. I do know that they ship for a gent who shoots around the country. When he arrives at his hotel his ammo is waiting there for him. So they’ll ship to a residence. That’s all I have at this time.

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I do not get that magazine as the organization I compete in (GSSF) is Glock sponsored and Glock pistols only. The way I understand it, GSSF could be considered more like a “speed bullseye” match as accuracy plays a larger role, but there are no movements or reloads involved.

I’m not gonna ask you for that info at this time as I’m not in position to use that info right now. Maybe as I get better and I’m looking for those little bits of equipment improvement I will reach out if needed. I have a way to go before I’m competing at those top levels where ammo will make a significant difference. I do appreciate the offer and may hit you up for that some day down the road if I haven’t already run across it.

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It would be a really strange local match where they’d check your ammo for PF anyway. Generally it’s done at regional and higher matches. But you can still play the PF game if the manufacturer lists the velocity on the box or website.

The formula is (velocity (ft/sec) x bullet weight in grains) divided by 1000 = PF

Concentrate on the basics, trigger, sights, and let the speed follow on it’s own. No one can miss fast enough to get good scores.

I spent years shooting bullseye where the basics MUST be adhered to. When I moved to USPSA shooting I already had everything needed except speed. It took me awhile to speed up. I was never really the fastest shooter so anything I could do to minimize time between shots I took. I maximize what I can do, that’s how I stay ahead of some of the younger shooters. Steel Challenge I do really good at and give our master class shooter competition at times.

Fun times, good people. I have never heard a cross word spoken in the years I’ve been in the sport. Fellow shooters just want to see others have a good run and shoot safely. Some shooters may think they’re under a spotlight, and they are, but not in the way they think. Nothing but good vibes sent the shooters way.

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Thanks for the input, Brian. I completely agree about the fundamentals, I just have to get faster with them. I’m pushing my comfort zone a little with trying to improve my reaction time after recoil for my 2nd shots on target. If I can shave .3 seconds off of those shots while not increasing penalties, that amounts to about 8 seconds over the course of the match. I’ve also been working on muscle memory from buzzer to accurate first shot. My practice session Friday started out with me pushing beyond my comfort zone and time from buzzer to 2nd shot on target started out around 1.5 to 1.6 secs with time to first shot around 1.0 to 1.1. By the end of practice I was 1.2 to1.3 secs with first shot coming in around .87 to .91. That was on a 10" plate at around 11 yards. I really need to be shooting at an 8" plate, but that’s what I had to work with at the range. It will be different shooting at an unmarked cardboard target, but I’m confident I’ll get there if I keep putting in the work. I figure if I keep pushing past my comfort level, the uncomfortable will become comfortable then I can repeat the cycle.

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