Softest shooters for me were the 147gr loads. 115's had a bit sharper felt recoil, but less muzzle flip...if that makes any sense.

 

At the same power factor, lighter bullets have more energy (1/2 mv^2 and all that)

 

What division, what gun?



Darn, I don't see a place on the chronograph report for energy.
At the same power factor, the MATHEMATICAL recoil is the same, the ballistic recoil is greater for light bullets because of the jet effect of their larger powder charge. An Open gun profits from a lot of powder, lot of gas blowing out through the loudener.

Felt recoil? Shoot and feel.

 

I ran 9mm and .40 in USPSA and had good results with the mid-range weights of each.

My impressions were:
9mm - 115gr=Fast Slide Speed, snappy recoil, occasional jams / 124Gr = slower slide speed with more reasonable recoil / 147 = slower slide speed, not much muzzle rise, but the slide speed is noticeable and very controllable.

The .40 acted very similar with 180 / 200 / 220 grain bullets - and the 220gr or 240gr were Very Slow slide speed.

So... for faster follow up shots the lighter projectiles had the fastest slide speed and follow up shots in my experience.

Hope that helps!

 

So... for faster follow up shots the lighter projectiles had the fastest slide speed and follow up shots in my experience.

Hope that helps!

Why do very few people use 115 gr bullets in competition then?

(data from 2022 because it was the first one I could find on google)

Production Nationals

Carry Optics nationals

 

Chronograph doesn't report on felt recoil, and you're right, not only does a lighter bullet have more energy, but the powder has more energy and ejecta mass.

 

I have shot USPSA for 15 years and I have shot 115, 124, and 147 grain 9mm in multiple matches. For me, 124gr works best. Best control and best accuracy.

I would recommend you try your own testing and see.

 

I tend to do a little of my own testing, and I did not feel much difference between the 115gr and the 124gr, but I only shot one match with the 124gr...I have not tried anything heavier yet. I will have to chrono the two and see if there is a fps difference.

 

Of course the vel will be diff, 115 will be going faster.

 

For same PF, heavier bullets have a diff recoil impulse, more push than snap. Some of felt recoil is muzzle blast & 115gr @ 1200 have plenty. I also think its rotational torque that is causing the snappy feel. 115 @ 1150+ v 147 @ 900, no contest for me, 147. A 160 @ 820 is stupid soft but feels sluggish in a heavy slide gun like a 1911.

 

I guess I never thought about the accuracy part...The 115gr have been very accurate, and our club night guy likes to test us on that once in a while. So the heavier slower moving 147 grain are not as accurate?

 

Not at all. All 9mm I have run do just fine with 147. I suppose an accuracy base line should be established first. If you are capable of 2" 25y accuracy, then any 9mm bullet weight is up to that. If you are not capable, then the bullets inherent accuracy isnt relevant. For gun games, most shots are under 25y & requirement is 6-8" circle.

 

Recoil is momentum. Mass times velocity.

 

Yes but felt recoil has other factors To consider.

 

In my experience, with some calibers such as 45 ACP and 44 Special/Magnum, the lighter the bullet the less recoil, but with other calibers, such as the 9mm and the 40 S&W, the exact opposite is true. I learned this a long time ago when reloading 9mm for a S&W model 39 and I decided to try some cast 158 grain bullets that averaged over 160 grains using wheelweight alloy.

The fact that Lighter Bullet/Less Recoil is cartridge specific and is not true across the board, is just another example of how things don't always work the way we think they should according to our reasoning. Like with Bumblebees. Looking at the small wings and the large body, they shouldn't be able to fly and yet they do.

 

I'm sure that's because of factors beyond just the bullet weight. If you put a 115 and a 147 bullet on top of the same powder charge, the 147 is going to feel terrible.

 

For IDPA 9mm & USPSA Prod, CO my vote is for 135g... they split the difference b/t 147g & 124g. 124s are fine, 135s are a bit softer but you're not waiting on the slide/sights like you will eventually do with 147g. 135g seems to drop falling steel about as well as 147g, haven't had any poppers that needed help.

 

I love how people think they are waiting for the slide to cycle when shooting 147 grain bullets.

 

It puzzles me too.

I went through over 30K of 147s in 2023 and have been shooting them for most of 2024.

Just started experimenting with 124s.

To me the difference is very negligible.

I still can't outsplit the slide with 147s.

The whole "it returns faster" doesn't make a lot of sense to me. I've seen zero difference in the spacing of my hits or split speed with the lighter bullet. Felt recoil is slightly more, but not enough to affect my shooting either way.

It's basically a wash for me. I've now got a die set for both, so whatever I happen to be able to by cheapest. I guess there's a small advantage in that 124s will be slightly cheaper per bullet, but again negligible. Probably just stick with the 147s I think.

 

I have switched to the 124grainers....I was using the 115 grain, and I never had trouble dropping steel with them as long as I didn't hit low. The 124's seem a little better though. Recoil seems about the same.

 

That’s all a matter of preference. Some people like the “softer” recoil impulse of heavy slower bullets, and some people like the “snap” of lighter faster bullets.

If you can get your hands on a few hundred of each 115s, 124s, and 147s or the like, shoot them all back to back and see which one you like the best. You can also use a camera in slowmo and different recoil spring weights to see what combination actually shoots the flattest.

 

At the same power factor, lighter bullets have more energy (1/2 mv^2 and all that)

Chronograph doesn't report on felt recoil, and you're right, not only does a lighter bullet have more energy, but the powder has more energy and ejecta mass.

Two succinct posts that will be overlooked by the unwashed masses. Actual energy is a function of the square of velocity. This means that A) heavier bullets have a distinct advantage in the (flawed) PF calculation, and B) the relatively small mass of expanding gas from powder which easily reaches Mach 2+ contributes to actual energy in a significant way.

 

Engineering Geek :
[ Bullet Weight X Velocity ] plus [ complex math regarding residual gas pressure at muzzle ] modified by [ really complex math about rate of slide acceleration , total slide energy , rate curve of recoil spring , and drag of internal components generally, and probably some more I'm not thinking of yet .]

You are taking me back to the 1960s and the Dean Drive, as "explained" by Davis Mechanics and the Fourth Law of Motion. Hey, maybe we could use a mini-Dean to convert the rotation of the bullet into added velocity.

If you can get your hands on a few hundred of each 115s, 124s, and 147s or the like, shoot them all back to back and see which one you like the best.

What a thought, empirical testing. That seems to have been largely replaced by asking a bunch of strangers on the internet.

the (flawed) PF calculation,

Early days, before consumer chronographs, power factor momentum was measured directly with a ballistic pendulum. Very simple, for Major, your load had to swing the pendulum at least as far as GI .45 Ball fired from a Commander or Star PD. The shorter barrel provided a margin of error in the shooter's favor. A friend reported seeing a manufactured pendulum sold as "Peter the Power Meter."

 

Early days, before consumer chronographs, power factor momentum was measured directly with a ballistic pendulum. Very simple, for Major, your load had to swing the pendulum at least as far as GI .45 Ball fired from a Commander or Star PD. The shorter barrel provided a margin of error in the shooter's favor.

It was specifically set for the Star PD , because at the time , it was the shortest bbl serious pistol in .45acp.

 

The velocity of the slide plays a big part in felt recoil of an auto pistol. The snappy recoil of the 115s and the milder recoil of the 147s correspond with the 115s fast slide speed and the “waiting for the slide to go into battery with the 147.

 

That may hold for factory ammo (where the PFs are wildly different), but if you reload and can keep the PF consistent, heavier bullets will tend to have less felt recoil. If you fired a factory 115gr 9mm round followed by one of my 147gr handloads, you'd probably think you'd had a squib on the second shot. That was my reaction the first time I mixed my 124gr and 147gr handloads.

 

The balistic software suggests that the 105gr hybrid has slightly better wind drift performance at 1000yds than a 115 DTAC. I have shot the 6XC with both 105gr and 115gr bullets and they both performed well.

 

That's a pretty far shot for a 9mm

 

I was happy with 147. Cost me an extra ten bucks per 1000 for the bullets. Powder wise used 1.7 more grain per bullet with 115. All negligible to me. Was what I was comfortable with POA and recoil wise.

Carry 147 when I run run the Glocks as well so it's nice to be able to just reload one bullet for comp and training

 

IMO, best bullet weight comes down to a few questions.
1) How recoil sensitive are you?
2) How fast are you?

Some with really fast splits will complain that heavy bullets cycle the slide too slowly.
As mentioned in my previous post, the heavier the bullet (keeping PF constant), the less recoil you'll feel...so if you don't like recoil, go heavy.

I compromise and after starting out with 124gr, then switching to 147gr for a while, I settled on 135-138gr.

 

I've never heard a high level shooter say they are waiting for the slide to cycle. They might say it feels a certain way or maybe even feels sluggish (ever shoot 160gr 9mm or 200gr minor 40? lol) but waiting for the slide to cycle is nonsense.

 

Yes, I've loaded a test batch of 160g to try... didn't like them. We had 8 kids at Nationals shooting 9mm 1911s this year, and they do best when shooting 147g minor loads... the kids that tried 124g struggled with recoil; only one of the 8 kids is stout, the others are all pretty average build. We struggled with 1911 this year and finished 3rd. The match ammo was syntech 130g and it was actually pretty nice, not a big difference between that and 147g. Personally I loaded 2500 Blue 135g this month and really like 135 whether Blues, RMR, J-Ames, they're all great... I find the Blues easiest to load.

 

All my major* championships have been won with 124 grain bullets.

*major=tiny club outlaw fun matches