Felt recoil

[Tatume]

Hello Folks,

Today I fired Remington 200 grain round nosed bullets and RCBS 35-200-FN bullets in my 358 Winchester Browning BLR. It surprised me that the cast bullets gave more recoil than the jacketed bullets. The charge with the jacketed bullets was 3.0 grains more than the charge of the same powder with the cast bullets. The jacketed bullets were fired with a muzzle velocity of 2300 fps, and the cast muzzle velocity was 2200 fps. The cast bullets weigh 210 grains, and the jacketed bullets weigh 203 grains. The total ejecta mass for the cast bullets is 4.0 grains more, but muzzle velocity is 100 fps less. I’m surprised the felt recoil of the slower load was noticeably more.

I thought it was interesting. Any comments?

Take care, Tom

[popper]

boolit sizing in the bore!

[dverna]

Tom,

Which bullets did you fire first? Recoil is an 'additive' sensation. The more you shoot, the worse it gets.

There are only a few parameters that effect recoil energy. Mass and velocity of ejecta, and weight of the gun. Pressure has no effect.

Don Verna

[lwknight]

The slower the bullet , the more you will perceive recoil with exception to light loads of course.
Eg: a 30-30 can feel like as much recoil as a 30-06 but we know that is mechanically impossible.
It takes less powder to cycle a pistol with cast than jacketed bullets. Go figure.

[Tatume]

Don,

I was surprised at the perception of more recoil from the slower cast bullet load so I alternated some shots. The sensation of greater recoil from the cast bullet load was persistent. This load has four grains more combined bullet and powder mass, but is 100 fps slower. I don't believe recoil is actually greater, as momentum and energy are both less than the faster load. It's a puzzle.

Take care, Tom

[Tatume]

The slower the bullet , the more you will perceive recoil with exception to light loads of course.
Eg: a 30-30 can feel like as much recoil as a 30-06 but we know that is mechanically impossible.
It takes less powder to cycle a pistol with cast than jacketed bullets. Go figure.

Hi LW,

I don't understand why this should be so. Given equal bullet and powder mass, the slower bullet will generate less recoil. I would also expect the faster load to create a "sharper" and more objectionable recoil. Can you explain further?

Thanks, Tom

[Scharfschuetze]

Recoil can be pretty subjective, but your loads do sound close enough that one wouldn't notice a whole lot of difference. Is one load noticeably louder than the other? I think that the decibel level of a load may influence one's perceptions.

At anyrate, here's a link that helps you do the math for recoil. You can compare your two loads as to their actual momentum or foot pounds of recoil in your rifle.

http://kwk.us/recoil.html

[hickfu]

boolit sizing in the bore!

I agree with popper, I think it would be a combination of the slower boolit being sized in your barrel... the more perceived recoil

Im not an engineer so maybe my head is up the wrong place



Doc

[rhead]

Tom,

Which bullets did you fire first? Recoil is an 'additive' sensation. The more you shoot, the worse it gets.

There are only a few parameters that effect recoil energy. Mass and velocity of ejecta, and weight of the gun. Pressure has no effect.

Don Verna

It is a secondary effect but the pressure at the muzzle DOES effect the velocity of the the gasses that do contribute to the recoil along with the weight of the powder charge. Still i would have guessed that the boolit would have less pressure at the muzzle in the two above mentioned loads.

I agree "Interesting" if I think of a logical reason I will jump back in.

[CastingFool]

Felt recoil is affected by a combination of factors, which have already been mentioned. Once, I was out shooting one of my rifles (with jacketed bullets) 150 gr sp at 2800 fps (published data) out of a 30-06, and 130 gr sp at 3100 fps, same rifle. Can't recall the exact powder charge, but I do remember the powder charge for the 130 gr bullet was something like 4 gr higher. The felt recoil was noticeably higher with the lighter bullet, and that was surprising to me.

[imashooter2]

boolit sizing in the bore!

Please explain how this equates to higher perceived recoil.

[jonp]

Please explain how this equates to higher perceived recoil.

? Recoil impulse slowed by friction of the projectile delaying the gas expulsion from the muzzle.

[imashooter2]

? Recoil impulse slowed by friction of the projectile delaying the gas expulsion from the muzzle.

Lower velocity would by itself delay the gas expulsion from the muzzle, but resistance from the boolit? I don't see it.

ETA: Friction or resistance from movement of the boolit is contained within the rifle. Friction from the boolit does not pull the buttstock forward or retard its movement aft. Acceleration of the ejecta is what causes recoil.

[MtGun44]

Perceived recoil is highly subjective, and the point of muzzle blast affecting the perception
is probably good.

What powders? With a faster powder, you achieve the same velocity in a shorter time - this
requires a higher acceleration - which will be perceived as higher recoil. With a slower powder
the acceleration is longer at a lower level, same velocity can be obtained - but less acceleration
applied to the boolit, less recoil to you.

Imagine you have 150 yds (barrel length) and accelerate hard for 3.5 seconds in your
hot performance car, then coast for the rest of the distance. Then you accelerate smoothly,
still accelerating at the same or nearly the same rate all the way to the end of the
150 yds. You could find an acceleration which would get you to the same end
speed WITH MUCH LOWER PEAK ACCELERATION.

This instantaneous peak is what is perceived. I would guess you were using a faster
burning powder with the cast than with the jbullet.

Bill

[Tatume]

I would guess you were using a faster burning powder with the cast than with the jbullet.


The charge with the jacketed bullets was 3.0 grains more than the charge of the same powder with the cast bullets

Hi Bill, 4895 both bullets. Take care, Tom

[MostlyLeverGuns]

Muzzle blast and loudness or noise result from whatever muzzle pressure results. Could be the lead bullets leave more energy (from the powder) exiting the muzzle resulting in higher perceived recoil. The jacketed bullets, with their higher friction and increased velocity consume more energy getting down the barrel, leaving less for muzzle blast, noise, perceived recoil. ? ? ? ? Maybe ?

[AABEN]

You might think about using Moly on your cast bullets. It will make a different!

[lwknight]

On the opposite end of Mtgun44, the actual duration of recoil affects perception. Sure a heavier rifle can seem to punch harder but actually put less pressure on your shoulder. Then the opposite with a different rifle.

I really can't give a good scientific explanation other than a culmination of factors like the jet affect. A slower powder can seem to kick more than a faster powder.

You just need to get a bigger gun so you can measure how far it scoots you back on the bench to really compare recoil. LOL! Seriously though, perception is a tricky thing to behold.