I was playing around with Beartooth Bullet's recoil calculator and noticed that different powders used different amounts to get the same velocity. Sometimes a lot.

Just as a rough example in the .375 H&H & a 300 grain bullet one powder might use 61 grains for 2500 fps while another powder would use 75 or more grains to get 2500 fps.

Which is certinaly not a problem but when when using the recoil calculator it showed a difference of as much as 6 fp of recoil and 2 or more fps of recoil velocity for the same MV.
For the same weight bullet and same MV, percentage wise thats a fairly large increase.

So I wandered, is the recoil calculator correct?

Or is the difference in the recoil noticeable in the real world?

If so, is it worthwhile trying to find a load that uses the smallest amount of powder that achieves the target velocity?

I would assume it would easier or would have more options load wise to do this if not looking for a max load.

Is it that faster or slower burning that are making this difference?

I just found the numbers interesting and wanted to know if any of this translated into the real world?

Allen

Recoil is a product of the mass/velocity of the EJECTA. Your only thinking of one portion of the ejecta, the bullet, and not the other component of it IE the mass of the gass itself, which is moving (for calculation purposes) at approx 1.5 times the velocity of the bullet.

So yes, the difference in powder does have an effect. Faster powders not only need a smaller amount, they exit at a slightly lower velocity, while the slower powders take more and have a higher exit velocity.

Is it worthwhile worring about it? The most important thing (to me) is which one gives me the best groups.

Hey Allen, It is particularly noticable if a person is doing a lot of shooting with a "Shotgun". And it "feels" different than the numbers suggest, or at least it does to me.

Used to use a lot of very Fast Shotgun Powders and at the end of a shoot, I would be ready to quit - for a couple of days. Fortunately the wisdom of the Elders got passed along to go to a Slower Powder with an amout to match the velocity I'd been shooting. This actually created less Pressure and spread the recoil out over a longer time.

It would be similar to getting a quick Jab when Boxing compared to a heavy Shove.

If you look in the Load Data for Shotguns, you can see what I'm talking about with more Powder creating less Pressure. Of course that is because the Burn Time (dv/dt) is slightly increased. And for me, it was very noticable at the end of a shoot, because my shoulder wasn't nearly as sore/tired.

Good question.

Hot Core is making the opposite argument, but we're mixing apples and oranges here.

He is correct that the slightly slower "start" of slow burning powders can spread the recoil impulse over a longer period of time. HOWEVER, as Tailgunner correctly points out, the greater total ejecta makes the total recoil greater.

The recoil calculator does not attempt to compensate for time/velocity differences, but merely assumes those factors to be equal for purposes of its calculation.

But here's the bottom line: In a centerfire rifle, the actual difference in perceived recoil is negligible for a given bullet at a given muzzle velocity no matter how disparate the powder charges. In shotguns, many shooters swear by one or another powder/wad combination to achieve less perceived recoil with the same velocity performance. I heavily discount this and belive there to be little, if any, difference. When target shooters want less recoil, they use less shot at a lower velocity. But I'll be the last to deny a particular trap shooter his favorite load because I have no doubt that he perceives its recoil and performance to be superior to some other load -- and for him, it is!

quote:

Originally posted by AllenBosely:

Or is the difference in the recoil noticeable in the real world?

Is your shoulder so highly calibrated that you can sense a difference of 6 foot pounds when firing a 375 magnum? I will go out on a limb and say, NO!

Let's not forget that the powder doesn't lose any mass once burned. The mass is still there and will be leaving the barrel right behind the bullet. The extra several grains of powder is just like using a heavier bullet. Any powder still burning after the bullet exits the barrel also acts like a rocket engine.

Ken....