Shiloh Rifle Forums

Dennis Armistead wrote:

BFD wrote:So, whats the physics of that? Is the .50-70 so much faster? I'm curious.

I'm just a ol' country boy...not a physics major, but this is my own experience owning both. When you're on the line and two shooters are shooting...one a .45 and the other a .50, using the same gr. round, same powder capacity you can tell who's shooting the .50....Maybe someone on the board who shoots both can explain (better) the difference between recoil, torque of the .45 vs .50.
Dennis

Dennis
Being new to the forum you probably have not read my 2008 post about recoil and the relative efficiency of different sharps calibers.
Given just the bullet weight and the bp charge weight, there will be a difference between recoil of different calibers, but can't compute (too many variables).
BUT, given the same bullet weight, velocity, powder charge and rifle weight, the recoil will be the same in a .22 cal as in a 4 bore!!!.
Caliber makes no difference, but people should realize that the contribution to recoil of any number of grains of black powder will contribute less than half that of smokeless powder. Forgetting to consider that is what makes BPCR shooters' claim to HUGE recoil just MACHO talk. Of course, 200 rounds with less than huge recoil can be a bother.

SharpsShooter2B wrote:

Dennis Armistead wrote:

BFD wrote:So, whats the physics of that? Is the .50-70 so much faster? I'm curious.

I'm just a ol' country boy...not a physics major, but this is my own experience owning both. When you're on the line and two shooters are shooting...one a .45 and the other a .50, using the same gr. round, same powder capacity you can tell who's shooting the .50....Maybe someone on the board who shoots both can explain (better) the difference between recoil, torque of the .45 vs .50.
Dennis

Dennis
Being new to the forum you probably have not read my 2008 post about recoil and the relative efficiency of different sharps calibers.
Given just the bullet weight and the bp charge weight, there will be a difference between recoil of different calibers, but can't compute (too many variables).
BUT, given the same bullet weight, velocity, powder charge and rifle weight, the recoil will be the same in a .22 cal as in a 4 bore!!!.
Caliber makes no difference, but people should realize that the contribution to recoil of any number of grains of black powder will contribute less than half that of smokeless powder. Forgetting to consider that is what makes BPCR shooters' claim to HUGE recoil just MACHO talk. Of course, 200 rounds with less than huge recoil can be a bother.

BFD,
I'm not new to the forum, It shows 19 posts under my name, but since I didn't post on the forum for quite a few years, my log in was dropped. No disrespect to your education on physics...I think your thinking on this is flawed. Coefficient of friction from a .22 vs a 4 bore being of equal weight will be different. This is not a gravity lesson. A 550 gr. 45 cal round 1.3" long and a 550 gr .50 cal round 1.3 long are not equal when it comes to friction going down a bbl. Like I said..I'm just a Ol' country boy who shoots both and can tell the difference. No sense continuing this discussion, I'm not arguing who's right or wrong.
Dennis

Well, I'm trying to understand the difference, because frankly, I don't see it. I've shot a 10 bore shotgun fairly extensively with loads far in excess of what your .50 shoots. Yet it was only a 9 lb gun and recoil was not really that noticeable. I don't see why a .50 that is similar in weight of gun, powder and lead would be much different than a .45.

Coefficients of friction are unknown, and perhaps irrelevant. I know for sure, your post count is irrelevant.

Like Dennis, I'm just trying to understand where this comes from.

BFD wrote:Well, I'm trying to understand the difference, because frankly, I don't see it. I've shot a 10 bore shotgun fairly extensively with loads far in excess of what your .50 shoots. Yet it was only a 9 lb gun and recoil was not really that noticeable. I don't see why a .50 that is similar in weight of gun, powder and lead would be much different than a .45.

Coefficients of friction are unknown, and perhaps irrelevant. I know for sure, your post count is irrelevant.

Like Dennis, I'm just trying to understand where this comes from.

One thing for sur...I know Troll when I see one!

You seem to be myoptic

BFD wrote:You seem to be myoptic

Not at all...just Pragmatic.
Dennis

Whatever makes you happy.

Whatever makes you happy.

For interest I ran the Don Miller Stability Factor (Sg) for 1200 fps:

50 caliber 22 Twist:

350 grains Sg = 7.96
450 grains Sg = 4.81
540 grains Sg = 3.59
600 grains Sg = 3.01

50 caliber 36 Twist:

350 grains Sg = 2.97
450 grains Sg = 1.80
540 grains Sg = 1.34
600 grains Sg = 1.13

Bullets are too long and will tumble if the Sg is less than 1.4
Sg greater than 2.0; then bullets are overspinning.

Don Miller stability evaluation would suggest a 36 twist would be better and not to shoot bullets longer than about 500 grains.
The Don Miller stability factor is a very good predictor for shooting out to 500 yards.
However many long range shooters believe you need to overspin bullets for long range shooting.

So what happens if we go to a bit tighter twist than 36 to use heavier longer bullets:

50 caliber 34 Twist:

350 grains Sg = 3.33
450 grains Sg = 2.02
540 grains Sg = 1.39
600 grains Sg = 1.26

50 caliber 32 Twist:

350 grains Sg = 3.76
450 grains Sg = 2.28
540 grains Sg = 1.69
600 grains Sg = 1.42


Yes the recommendation to use a 32 twist would be better for 500 to 600 grain bullets with just a little bit of overspin for 450 grain bullets.
Still not enough twist at 34 for the longer heavier bullets over 500 grains.

SchuetzenDave, thanks for the data.

SchuetzenDave wrote:For interest I ran the Don Miller Stability Factor (Sg) for 1200 fps:

50 caliber 22 Twist:

350 grains Sg = 7.96
450 grains Sg = 4.81
540 grains Sg = 3.59
600 grains Sg = 3.01

50 caliber 36 Twist:

350 grains Sg = 2.97
450 grains Sg = 1.80
540 grains Sg = 1.34
600 grains Sg = 1.13

Bullets are too long and will tumble if the Sg is less than 1.4
Sg greater than 2.0; then bullets are overspinning.

Don Miller stability evaluation would suggest a 36 twist would be better and not to shoot bullets longer than about 500 grains.
The Don Miller stability factor is a very good predictor for shooting out to 500 yards.
However many long range shooters believe you need to overspin bullets for long range shooting.

My 50-140 has a 1 in 36" twist and my modified RCBS patch to groove dia paper patch bullet mold throws them at 570 grs 1 in 30 alloy. The last time I used it at the Q, I went 6/8 on the buffalo at 805 yds with a paper plate size group. According to your analysis that would not have been possible. Your generalities are in the way of known facts based on experience I've had. At 600 grs stability is suspect but not at 570 with this twist. bobw

The stability factor changes based on velocity, atmospheric pressure, elevation and temperature.

I used normal conditions to calculate the Sg.

Looks like the environmental conditions helped you out that day BOBW.

But I would not rely on it happening most of the time.

For long range the nose shape of the bullet becomes more important.

With more time in the air and the affects of friction, the bullet drag becomes more important for long range predictions.

These are not important and are not part of the Don Miller model which is a predictor out to 500 yards.

Ok, bear with me for a moment, as I am not as knowledgable as most of you. With current focus on these ballistics calculators, the twist in the 45-70 is 1in18, so why isn't anybody preaching a way slower twist rate in this caliber for lighter bullets in addition to the 50-70? If you use these calculators, my 45-70s put the 405 grainers I shoot at 6-7Sg--but they shoot great. According to these calculators, they spin way too fast to be great.