Slide Velocity

[rhyrlik]

Hi Folks,

What's going to have a higher slide velocity:

A 90gr bullet doing 1500 FPS or a 147gr bullet doing 1000 FPS?

All the recoil calculatots say they should be the same. But which one's gonna be more snappy?

Thanks for your input.

Ralph

[Harmon]

The 90 grain bullet is going to "feel" snappier, due to the faster recoil impulse(faster bullet, less barrel time)

harmon

[gm iprod]

All things being equal, same firearm, equal Muzzle Energy (not power factor), powder charge and recoil spring weight, then slide velocity "should" be the same.

As Harmon says, the lighter bullet will feel snappier at the same power factor. But using the velocity parameters you gave then the Heavier & Slower load will give less recoil energy, simply because it has less muzzle energy. May feel softer, but some people say slugish. All the folks I know that shoot 9mm in a Production or Iron sighted handgun seem to prefer the big and slow theory, but mess with the recoil springs to get the action cycling slick.

You have to try both and see what suits your firearm and more imprtantly, your style of shooting.

[Chris Keen]

I prefer a lighter bullet = quicker sight return.

[Shay1911]

Power factor is the same, but velocity is higher. If you shoot a slow 147, you can actually see the slide moving back and forth. If you shoot, same power factor, 115's or 95's, the slide will move much faster. The front sight waits for you like a golden retriever with a ball in its mouth.

[Merlin Orr]

The front sight waits for you like a golden retriever with a ball in its mouth.

Priceless.

[AikiDale]

Does anyone have objective measurements of slide travel time? Are these perceptions borne out empirically or are they our perceptions?

Former 12 year old with a chemistry set wants to know.

[gm iprod]

Send as note to the two twerps on Mythbusters, they have a high speed camera. I work on how far the brass lands, if the slide moves back at X then the brass is also moving at X. Slower heavier bullets (therefore less muzzle energy) = empty cases slightly closer, and sometimes at a different angle.

This testing was done with a 38Super NRA Metallic sight gun, this gun does not lock the barrel at the front of the slide it resides in a bushing mounted on the frame. The slide when unlocked has very little drag on it once out of battery (6" barrel and 4 3/4" slide) I run a 12lb Wolff variable recoil spring at 125pf, we were trying to find what "felt" softer and returned the sight to target quicker. We finally settled on the middle ground, the 125gr at 1000fps. We tried 115gr at 1100 fps (308Ft lbs / 126pf), 125gr at 1000 fps (277ft lbs / 125pf) and 147 at 850fps (235ft lbs / 124.9pf), same cases, same primer, same powder obviously different charge weights, which has an effect on actual recoil energy figures. The mover was the settling factor, lead v's muzzle lift. Plates no different, weak handed slightly in favour of the heavier bullets. Barricade not enough difference in my scores. The other issue was point of aim at 50y v's 10y on Practical. Especially prone v's standing. For IPSC production I would shoot the heavy slow for my style of shooting.

The slower they went the "softer" it felt, the closer the brass stayed. Even though the Power Factor remained effectively the same the muzzle energy dropped dramatically.

Free Recoil of firearm. http://www.handloads.com/calc/recoil.asp

3lb handgun.

147 at 850fps = 0.62lbs seconds / 6.62fps / 2.04ft lbs

115 at 1100fps = 0.64 lbs sec / 6.84fps / 2.18ft lbs = 6% more recoil.

I used TG but if you use a slower burning powder you will get a little more felt recoil.

Power factor is the same, but velocity is higher. If you shoot a slow 147, you can actually see the slide moving back and forth. If you shoot, same power factor, 115's or 95's, the slide will move much faster. The front sight waits for you like a golden retriever with a ball in its mouth.

Exactly what I found, but described waaaaaay better.