Light fast or slow heavy for lowest recoil?

[Wich1911]

I'm fairly new to USPSA and running a 1911 in .45. I heard a guy say the other day that for a given power factor, a heavier bullet moving at lower velocity produces less felt recoil than a lighter bullet traveling faster, loaded to the same power factor. Is his statement correct? In terms of basic physics, power factor is a measure of power, or energy, at the muzzle, and every action results in an equal and opposite reaction, right? So theoretically the recoil energy would seem to me to be equal with the two loads.

If you were in my shoes and trying to pick a standard load to run thousands of, would you go with the 230 gr. or 185 gr. ball (all other variables being equal)? Both loads run flawlessly in my gun, and I have not been able to discern an accuracy difference between the two.

[cnote]

Heavy bullet and fast power = softer recoil is the rumor

[wgj3]

That is definitely the general consensus. Some would also argue that the lighter, "snappier" loads with lighter bullets can help you go faster. Once you start getting a feel for a particular pistol and have a little better understanding of how it performs with different recoil springs, you might find that lighter bullet/higher velocity loads complete the recoil cycle faster and get you back on target quicjer for your 2nd round.

I ran a bunch of 185gr MG .45 bullets before I switched to Limited.

[Wich1911]

Heavy bullet and fast power = softer recoil is the rumor

Fast-burning powder?

[Wich1911]

I ran a bunch of 185gr MG .45 bullets before I switched to Limited.

Meaning, you no longer shoot .45 in Limited? I have been saving my pennies for an STI Edge in .45 to run in Limited. Is this not a good idea? Would I be better suited running 9mm?

[Sarge]

I ran a bunch of 185gr MG .45 bullets before I switched to Limited.

Meaning, you no longer shoot .45 in Limited? I have been saving my pennies for an STI Edge in .45 to run in Limited. Is this not a good idea? Would I be better suited running 9mm?

Wich, you have a lot of research to do my friend. The good news is, this is the place to do it.

Look up burn rate charts for gun powder. There is a scale from slow to fast. Faster powders with a heavier bullet feel good. Slow powder with light bullets create a lot of gas to run the comps on open guns which makes them flatter and smoother to shoot.

In limited you either want to run a .40 for MAJOR scoring or a 9mm for minor scoring. They are described in the rule book. Using a 45 is overkill and it greatly reduces the number of rounds you get in a mag. 45 is single stack MAJOR ammo.

[Wich1911]

Wich, you have a lot of research to do my friend. The good news is, this is the place to do it.

Look up burn rate charts for gun powder. There is a scale from slow to fast. Faster powders with a heavier bullet feel good. Slow powder with light bullets create a lot of gas to run the comps on open guns which makes them flatter and smoother to shoot.

In limited you either want to run a .40 for MAJOR scoring or a 9mm for minor scoring. They are described in the rule book. Using a 45 is overkill and it greatly reduces the number of rounds you get in a mag. 45 is single stack MAJOR ammo.

Thanks, Sarge.

Roger that on the burn rate charts. Cnote said "fast power," so I was just confirming that he meant fast-burning POWDER.

Really? No one shoots .45 in Limited? It can be loaded down to the 170 PF just fine, and STI 2011s chambered in .40 only hold three more rounds in the mags than those chambered in .45. Granted, I have seen stages that would require an extra reload in the 45 and not in the 40.

[copecowboy22]

I'm using 200 gr bullets and titegroup in 45. The 40 vs 45 in limited is debate is on hear a lot. In an STI I think it's 2-3 rounds difference in mag capacity. It's do-able but a slight disadvantage in limited.

[mlmiller1]

Can you get 19rds 45 in an sti mag? I shoot glocks but i think most sti limited guys are getting 21 or 22 in a mag. I thought you could only get 14 45s in a mag.....

[Wich1911]

Can you get 19rds 45 in an sti mag? I shoot glocks but i think most sti limited guys are getting 21 or 22 in a mag. I thought you could only get 14 45s in a mag.....

That's right. 14 rounds of 45, or 17 rounds of .40, so if shooting major, .40 has a three-round advantage.

[SilverBolt]

Wich,

My 140mm .40 mags hold 20 rounds reloadable or 21 packed tight. My 140mm 9mm hold 23 reloadable. If you are limited to 14 rounds that is a significant disadvantage.

[wgj3]

You can most defintely get 22 in a legal .40 mag. 21 is pretty easy and 20 is a given. Dont think you can anywhere near that with .45.

[kneelingatlas]

Can you get 19rds 45 in an sti mag? I shoot glocks but i think most sti limited guys are getting 21 or 22 in a mag. I thought you could only get 14 45s in a mag.....

That's right. 14 rounds of 45, or 17 rounds of .40, so if shooting major, .40 has a three-round advantage.

Wich,

The big problem with .45 in Limited is that you can't get over the 16 round threshold, with 8 shot arrays, if you have 14 rounds in the mag you still have to reload every time you move on most stages. If you don't have at least 16 rounds, you might as well have 10.

[bajaholic]

I shoot 45, LTD. Yes it is a disadvantage overall compared to the 40. There is a number of times, not having to reload would be very nice. My (stock) mags state they hold 14, but you cant really load them full, they don't seat well. (generally load 12 but 13 in my first mag)

The other difference in 40 compared to 45 is the cost of shooting, 40 rounds are much cheaper.

That being said, I have a 45 (Para Pro Custom,2011) And I purchased it because the gun was substantially less expensive than the other models available in 40. My budget at the time was easier to justify the 45.

It has been a great training gun for me. By creating more work in the beginning (reloads, recoil,etc) It has made me a better shooter faster. Granted I have a long way to go, but in my opinion having the gun I have has helped. I am not expecting to be in the winners circle at this point, number one because I am a beginner, but there is most definitely a disadvantage with fewer rounds. But I am having fun learning!!!

Down the road, I plan to upgrade to a 40 platform, with a more custom build. Just need to justify the budget... But if I was starting from scratch again.... I would have spent the money on the pricier gun in the beginning rather than the more expensive ammo...

[kneelingatlas]

In terms of basic physics, power factor is a measure of power, or energy, at the muzzle, and every action results in an equal and opposite reaction, right?

Power factor is a momentum formula (mass times velocity), not an energy formula (mass times velocity squared); the muzzle energy of a light bullet like 115gr @ 1,435fps is more than double the muzzle energy of a heavy bullet like a 230gr @ 718fps (536ft.lbf vs 263ft.lbf) at the same PF.

I don't think anyone would argue with the statement that a 230gr bullet traveling 718fps shoots softer than a 115gr bullet traveling 1,435fps from the same pistol, but plenty here will argue that muzzle energy is not a good predictor of recoil impulse and since I'm not a professional physicist I try not to engage in such debates.

Reducing a concept like recoil "feel" to a simple calculation is a very difficult task so I think I'm in the majority when I say anecdotal evidence is good enough to conclude heavier bullets at lower velocities shoot softer in non-compensated pistols (gas volume is the name of the game once you introduce a comp, so more powder equals more gas).

Bullet Kinetic Energy Calculator

Edited September 26, 2014 by kneelingatlas

[kneelingatlas]

and here's a burn rate chart for you: http://www.hodgdon.com/burn-rate.html

[jroback]

After reading this thread, I thought -- lets do a calculation. I believe that Newton's third law is applicable here (for every action there is a equal and opposite reaction), which is based on forces, not momentum or energy. By my rough calculations (using atlas' numbers), the 115 gr bullet produces a force of 2.85E8 gr*ft/sec2 while the 230 gr bullet produces a force of 1.42E8. So firing the 115 gr bullet should produce ~ 2X the force back into the shooter as the heavier bullet, which is consistent with atlas' conclusions. The other interesting conclusion from this calculation is that since the slide mass is constant, the slide should accelerate backwards towards the shooter twice as fast with the 115 gr bullet than with the 230 gr bullet. Of course, this does not take into account the spring which is opposing the slide movement, or the fact that the muzzle flips so some of the linear acceleration then becomes rotational -- unfortunately, I have reached the limits of my physics knowledge so someone else will have to do those calculation...

In an example more relevant to my shooting, I've been buying my ammo from Freedom Munitions, typically choosing between the 115 gr (1100 fps) and the 147 gr (950 fps). The 115 gr only generates 13% more force than the 147 gr, and the slide only moves backwards with 13% greater acceleration. Their 124 gr ammo exerts only 2% more force than the 115 gr. In my experience, I can't really tell the difference between these loads based on felt recoil.

It would be interesting to have your buddy load a variety of different ammos into your mag (in a known order, of course) and then see if you can correctly determine which was which based just on the felt recoil. I'm pretty sure I couldn't.

[kneelingatlas]

Thanks for those calculations John, I just wanted to add something to what you said about the rotational motion during recoil: I was not very happy with my first attempt at lightening a Limited slide where I took 1.8oz out of the front of the slide, but my second attempt took 0.5 oz from the rear, 1.2oz from the front and I couldn't be happier with it! I think this has everything to do with the geometry of your wrist and weight of the portion of the slide which crosses that fulcrum point. Anyone thinking of having their slide weight reduced, please take a look at this thread by CHA-LEE (Real testing and feedback on Slide Lightening) it's the best I've read on the subject.

[wgj3]

Agree 100% that the differences are quite minimal, but I am quite confident one given recoil impulse/"speed" can work better for a given shooter than another.

[Gooldylocks]

Can you get 19rds 45 in an sti mag? I shoot glocks but i think most sti limited guys are getting 21 or 22 in a mag. I thought you could only get 14 45s in a mag.....

That's right. 14 rounds of 45, or 17 rounds of .40, so if shooting major, .40 has a three-round advantage.

I think you are looking at stock magazines. In Limited Division, since the magazine length is the only restricition, aftermarket guts and basepads can get higher capacities than that. In a 45 glock you can get 17 rounds I believe, in a 40 glock it is 20 so a difference of 3 (however 3 can be quite a big difference). However in the 2011 platform you aren't going to be able to get over that 16-17 rounds in the 45 while you can get 21 or 22 in 40.

The one exception to the rule that I have heard of would be the para 14-45 (the pro custom mentioned above). I have heard 18 rounds of 45 is possible in one of those. Don't quote me on it though.

[jroback]

Atlas: the slide lightening issue is interesting. Intuitively, I agree that when the slide has moved its maximum distance to the rear, and the wrist is considered a fulcrum, then the relative amount of slide weight in front of the wrist vs. the amount of slide weight behind the wrist probably has an effect on felt recoil. Interestingly, by lightening the slide you should be increasing its acceleration to the rear, but the effect of changing the weight distribution around the fulcrum must more than compensate for that giving you the reduced felt recoil you found. Sure would be interesting if someone had the wherewithal to to calculate what was actually happening. It might lead to some interesting ways to reduce felt recoil through combinations of slide weight distribution, spring weights, bullet masses, and powder.

[L3324temp]

A 230 with Clays is the ticket.

[Sandbagger123]

I think one of the reasons the 45 is not as popular as 40 for limited is that brass is more expensive. Unless you have a ready source of 45 brass it's hard to scrounge it as I have found most 45 shooters tend to be quite protective of their brass.

[Wich1911]

That's right, Goooldy, I was just looking at STI's page on stock mag capacity for the .40. I see now that with aftermarket basepads, etc., it can hold 21+. That's quite an advantage over 14 rounds of 45.

[superdude]

The discussion over bullet weight and recoil might find the article below of interest:

http://www.shootingtimes.com/reloading/power-factor-recoil-bullet-weight-gives-edge/