180 grain .45 vs 180 grain .40

[kneelingatlas]

I'm pretty new to USPSA and just getting started reloading so I'm just starting to understand the difference in feel between bullet weights. From what I gather, at any given PF, the heavier, slower bullet is more of a soft push and the lighter, faster bullet is snappier, but what about the same weight bullet at the same speed in different calibers?

The reason I ask is that I'm lusting after a 6" gun (Witness Hunter), but I can only find it in .45 (I would prefer .40 for Limited). I've owned a few .45s and have always preferred the recoil impulse of my .40, can I use a light bullet to make the .45 feel more like a .40? I wouldn't mind shooting L10 with the .45.

I've never really given .45 a fair comparison since my .40 is a full dust cover 5" gun (CZ TS) and the .45 was a 4 1/2" gun with a short dust cover (Witness).

Does anyone have any experience with this?

Edited April 4, 2013 by kneelingatlas

[bikerburgess]

All other things being equal it should be as close to the same feel as you can get. if you like the idea of playing in L10 and prefer the push of heavy bullets you can go to heavier bullets in 45 than you can in 40. You can also often find the hunters in 10mm but the brass is a bit more expensive it would then be possible to rebarrel for 40 if EAA has or would get a 6" 40 barrel.

Mike

[56hawk]

According to my calculations, the 45 will have about 10% more recoil due to the increase in the powder charge. Doubt that it will be enough of a difference for you to be able to tell though.

[kneelingatlas]

Thanks for the advice guys, I'm thinking I might just have to grab it...

[superdude]

I did that test comparing 180 grain bullets in the 40 S&W and the 38 Super. I didn’t have a 180 grain bullet for the 45. Design: used the same gunpowder (WAP) and guns of the same weight (41.55 oz). Recoil was measured with a mechanical device that records distance moved.

Calculations were determined for the same velocity of 916.7 fps (165 power factor). Recoil (distance moved) and gunpowder charge weight were calculated by linear interpolation.

Charge weight. The 38 Super required less gunpowder (4.7 grains) than the 40 S&W (5.5 grains) for the same velocity. Note, there are several factors that could account for this, i.e. different barrels.

Recoil. The 38 Super had 6% less recoil than the 40 S&W for the same velocity. So, the smaller caliber produced less recoil with the same bullet weight at the same velocity, but it’s not a big difference.

Also, results show that within the same caliber, a heavy bullet does produce less recoil at the same power factor with a non-compensated pistol. (http://38super.net/Pages/Recoil.html#Anchor-47857)

Edited April 8, 2013 by superdude

[juan]

I did that test comparing 180 grain bullets in the 40 S&W and the 38 Super. I didn’t have a 180 grain bullet for the 45. Design: used the same gunpowder (WAP) and guns of the same weight (41.55 oz). Recoil was measured with a mechanical device that records distance moved.

Calculations were determined for the same velocity of 916.7 fps (165 power factor). Recoil (distance moved) and gunpowder charge weight were calculated by linear interpolation.

Charge weight. The 38 Super required less gunpowder (4.7 grains) than the 40 S&W (5.5 grains) for the same velocity. Note, there are several factors that could account for this, i.e. different barrels.

Recoil. The 38 Super had 6% less recoil than the 40 S&W for the same velocity. So, the smaller caliber produced less recoil with the same bullet weight at the same velocity, but it’s not a big difference.

Also, results show that within the same caliber, a heavy bullet does produce less recoil at the same power factor with a non-compensated pistol. (http://38super.net/P...ml#Anchor-47857)

have you ever done your test, and just change recoil springs?

[superdude]

I did that test comparing 180 grain bullets in the 40 S&W and the 38 Super. I didn’t have a 180 grain bullet for the 45. Design: used the same gunpowder (WAP) and guns of the same weight (41.55 oz). Recoil was measured with a mechanical device that records distance moved.

Calculations were determined for the same velocity of 916.7 fps (165 power factor). Recoil (distance moved) and gunpowder charge weight were calculated by linear interpolation.

Charge weight. The 38 Super required less gunpowder (4.7 grains) than the 40 S&W (5.5 grains) for the same velocity. Note, there are several factors that could account for this, i.e. different barrels.

Recoil. The 38 Super had 6% less recoil than the 40 S&W for the same velocity. So, the smaller caliber produced less recoil with the same bullet weight at the same velocity, but it’s not a big difference.

Also, results show that within the same caliber, a heavy bullet does produce less recoil at the same power factor with a non-compensated pistol. (http://38super.net/P...ml#Anchor-47857)

have you ever done your test, and just change recoil springs?

I did a recoil spring test with 45 ACP and 230 grain bullets using 10, 12, 14, 16 and 18.5 lb springs. The results were not clear. I thought there was a very slight trend for less recoil as the recoil spring was stronger, but at the strongest weight (18.5) it reversed and had the same movement as the 10 & 12 lb springs. The difference in recoil during the change trend was very small (2.3%). Also, all of the springs except the 18.5 lb spring were new, so the test was imperfect. I considered this a preliminary test, and if I saw a difference I would repeat it with all new springs for the 'real deal.' But with such a small difference observed, and it was a difference between a 10/12 lb springs and a 16 lb spring, I'm not sure that there was a difference. At present I have no plans to repeat the test, but who knows. So, yes I did a preliminary test, with unclear results. If I had to go with the results I found, I would have to say there wasn't a difference. But really, I'd prefer to repeat it with all new springs before I could say. Even so, if there is a difference, it's pretty small. It might also be that my method is not sensitive to changes that we might feel while holding the gun.

[kneelingatlas]

That's some great data superdude, thanks for sharing.