45-70 Performance

I would have thought that the 45/70 with heavy for caliber would lack the crunch.
The 300 grain bullet can be driven much faster and it has more energy than the 400 grain + Bullet.

For Black Bear you are right. For penetrating 7' of Buffalo from the rear quarter the 300's (Does anyone even make a 300 Solid?) wouldn't have adequate pentration. It takes a heavy solidly constructed bullet to get the job done.

2000 lb thick skinned game isn't the same game as lighter thin skinned game. I suspect your hot 300's would work very well on Lion if bullet construction was adequate. The mild factory 405 grain Remington (known for its rapid expansion) did an excellent job on Ryan's Leopard.

I suspect a 500 grainer at 10% under .458 WM velocity will still get the job done. Might want to shorten the maximum range by 50 yards or so but then what's the point of "sniping" dangerous game?
 
For Black Bear you are right. For penetrating 7' of Buffalo from the rear quarter the 300's (Does anyone even make a 300 Solid?) wouldn't have adequate pentration. It takes a heavy solidly constructed bullet to get the job done.

2000 lb thick skinned game isn't the same game as lighter thin skinned game. I suspect your hot 300's would work very well on Lion if bullet construction was adequate. The mild factory 405 grain Remington (known for its rapid expansion) did an excellent job on Ryan's Leopard.

I suspect a 500 grainer at 10% under .458 WM velocity will still get the job done. Might want to shorten the maximum range by 50 yards or so but then what's the point of "sniping" dangerous game?

Precisely.

For straight-line penetration, momentum is king. The very heavy bullets may lack the KE, but they more than make up for it in momentum precisely because of their mass and SD.
 
Precisely.

For straight-line penetration, momentum is king. The very heavy bullets may lack the KE, but they more than make up for it in momentum precisely because of their mass and SD.


I do wish posters would note that Sectional Density is merely the average length of the bullet. For penetration the factor that is more relevant is the ration of weight(mass) to frontal area and the ballistic coefficient of that frontal area (which in the case of soft points is changed as it meets resistance).
 
I'm acutely aware of it. Methinks you're straining at gnats.
 
I do wish posters would note that Sectional Density is merely the average length of the bullet.

This is incorrect. All bullets of a given weight and diameter have the same sectional density regardless of length.

Sectional Density = Bullet Weight (Grains) divided by 7000 (grains in a pound) then divided by squared diameter.

Sectional Density is a reflection of mass per a given diameter.

As a general rule bullets with a large flat meplat tend to penetrate better. Theories such as pressure waves have been proposed as to why but I do know flat points have less of a tendency to tumble as they lose speed.
 
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Sectional Density = Bullet Weight divided by squared diameter.


Do the math. Given jacket and core construction resulting in similar density, we have mass divided by a proportion of cross section of the bullet. Or you can do it empirically. Get several bullets of different calibers but all with the same sectional density. The point shapes will vary, and to some degree the height will vary due to percentage of copper versus lead, but the average length of the bullet will be the same. A cast .224" wadcutter bullet compared to similarly shaped .357" and .451" bullets if the sectional density is the same, the length will be the same, but the proportion of length to width will be greater in the smaller diameter bullet.
 
Do the math. Given jacket and core construction resulting in similar density, we have mass divided by a proportion of cross section of the bullet. Or you can do it empirically. Get several bullets of different calibers but all with the same sectional density. The point shapes will vary, and to some degree the height will vary due to percentage of copper versus lead, but the average length of the bullet will be the same. A cast .224" wadcutter bullet compared to similarly shaped .357" and .451" bullets if the sectional density is the same, the length will be the same, but the proportion of length to width will be greater in the smaller diameter bullet.

Sectional Density = Bullet Weight (Grains) divided by 7000 (grains in a pound) then divided by squared diameter.

This is the only math that matters in sectional density.
The heavier the bullet the greater the sectional density for a given diameter. Length only comes into play because heavier bullets need to be longer if of similar construction.
My Barnes TSX bullets tend to be longer than lead core bullets of the same sectional density (same weight in my .375) because lead is heavier than copper. A 300 gr .375 TSX is longer than a 300 gr .375 Swift A Frame even though they have identical sectional density.
 
Sectional Density = Bullet Weight (Grains) divided by 7000 (grains in a pound) then divided by squared diameter.

This is the only math that matters in sectional density.
The heavier the bullet the greater the sectional density for a given diameter. Length only comes into play because heavier bullets need to be longer if of similar construction.
My Barnes TSX bullets tend to be longer than lead core bullets of the same sectional density (same weight in my .375) because lead is heavier than copper. A 300 gr .375 TSX is longer than a 300 gr .375 Swift A Frame even though they have identical sectional density.

Sectional Density is truly just a measure of mass per unit diameter. It is true that the taper of the jacket and average density of the bullet does make a difference in bullet length, but it is the MASS and Diameter that effect sectional density, not shape or length or anything else. What has more of an effect on ease of penetration is the shape of the nose. It is counter intuitive but at high velocity, blunted objects traverse fluids with higher stability and more easily that sharply pointed ones as long as there is some ogive shifts the center of mass toward the base.

Also, it is interesting to note that bullets of similar construction and similar sectional density appear to be about the same length. This is why a .600 nitro express bullet looks like a shotgun slug when its sectional density is .330 and a .416 bullet looks like a pencil when it is .330. While one is short and stout, it also has a lot more mass to stop by what it hits. This is why SD works as an approximation of penetration potential. I am of the belief that in homogeneous media, 2 bullets of identical construction which doesn't deform, also having the same SD, will penetrate the same... I think an experiment is in order.

Setup:

Load a .600 OK with a with an 824 grain brass turned bullet with 5 driving bands of equal width with a 0.434" meplat to 2,400 FPS.

Load a .375 H&H with a 300 grain brass turned bullet with 5 driving bands of equal width with a 0.263" meplat to 2,400 FPS.

Both bullets will have the same general shape, one will just be slightly stouter. Here's a mock up I threw together.
Brass turned.JPG


Fire them both into Ballistics Gel blocks 75" in length and see what depth of penetration you get.

My guess is that they would both be similar assuming the bullets didn't deform.
 
Pics or it never happened! :D Just kidding, but a hunt report with plenty of pictures would be great! I am sure it would be a unique an exciting read. Lever guns and Buff sounds exciting.
And thanks for the report on the Buffalo Bores. If you recovered any bullets it would be great to see some pics of those too.
Love to hear more detail on this...
 
Say you have two barrels of water. One barrel is 10" in diameter; the other is 20" and for convenience and to match the SD formula to get the area of each base we square them, so the 10" base has 100 sq in, the 20" has 400 sq in. So just to keep it simple, lets say water has a weight of 1 ounce per cu in and that we desire the magical "sectional density" of .250. We solve for the weight. Since SD= W/A then SDxA=W; .250x100= 25; or .250x400= 100. The water in both barrels will have an SD of .250. The 10" barrel will have 25 cu in of water and the 20" barrel will have 100 cu in of water. But since the surface area of the 20" barrel is 4 times larger than the 10" barrel, it needs 4 times the amount of water to have the same SD and therefore the same depth of water.

SD shows only the amount of material ahead of a given amount of surface area. Various materials have different densities and so will have different lengths for same diameters, but within materials of similar densities, bullets of same SDs will have same average lengths. Naturally a flat point will be shorter overall than a spitzer, but their average length will be the same. Bullet length is only indirectly part of the penetration function.

If thought is given to penetration it is concluded that the primary positive force of penetration is momentum, shown as Mass x Velocity. The negative forces are impediments to the bullets path and the Ballistic Coefficient (not to be confused with in flight BC) of the bullet. The terminal BC changes rapidly as the bullet contacts the impediments. varmint bullets turn into virtual shotshells with dozens of small pieces of bullet, each of which has a very small BC and gives up its velocity very quickly. the other extreme is the solid which maintains its shape and changes very little in the interactions with the impediments. Big game bullets fall in between the two designs. The bullet is pointed in order to slice through the air with minimal loss of velocity, then on impact the nose does two things. It flattens out so that it will meet the impediment with a surface that pushes rather than slices, and the diameter of the frontal area increases which creates a larger surface area to push through the impediment. Since this pushing requires more energy (momentum) than did slicing, the bullet transfers more of its energy to the impediment. the transfer results in an energy wave that stretches soft tissue beyond it's limits and the tissue is torn, so after the passing of the wave the tissue snaps back in place but is no longer functional because it is ripped apart.

So an effective big game bullet will be one that has a flat surface area as it passes through the animals tissue and sufficient diameter either before expansion or after if expansion is quick enough to be relevant. the surface shape and diameter is then combined with sufficient mass and velocity for the necessary momentum. Momentum is a little deceiving since two bullets with the same momentum will have entirely different reactions to impediments. A.224" 50 grain bullet can be driven fast enough to have the same momentum as a .308" 180 grain bullet, but the high velocity is shed at a much faster rate than the slower bullet, so massive shallow wounds result rather than less intense deeper wounds, But that said, penetration is a function of a bullets internal BC, it's retained mass, frontal area and its momentum. SD gives a quick shorthand indicator of potential penetration, but that is all that it is.
 
there is no point in having a s.d. over 0.3 to 0.32 unless you are shooting soft bullets that just keep expanding as they penetrate.
then you go for a solid with 0.3 to 0.32.
velocity also increases penetration if the bullet is reliable in not overexpanding.
long thin bullets can bend which will certainly reduce penetration, and they have to be spun fast to be stable in flight, but more importantly in flesh and bone.
bruce.
 
Agree with Edward and add the Punch brass bullet with lead filled base. IMHO, a good package for 45-70 and 90.
Grizzly Cartridge bought the rights to the Punch a while back and sells the 405 grain .458 Punch bullets and loaded .45-70 Punch cartridges at 2050 fps.
On a frontal brain shot at a little less velocity from my 45-90, the 430 grain Punch shot through an ele head and on into the body (so did 450 grain Northfork FPS). The same weight Punch from a 45-70 shot through (daylight hole) a 5/8 inch steel plate at the range.
Naturally the Punch and NF from 45-70 and 45-90 shot through cape buffalo also.
 
Chris G spoke of "the area under the curve" and I love that area under the VV N133 energy curve for my .405 loads. There is no visible spike as with most powders, but the energy is there at lower peak pressure.
My pressure curves are created with Pressure Trace II and make it obvious why N133 can provide equal velocity to many other powders with 10-12 k psi less peak pressure. This is really valuable with my double rifles.
 
I have always thought that the 45-70 could be loaded up to make a fine buff cartridge. This thread shows it can be done, and done well. I have three 45-2.1" guns, but recoil always prevented me from exploring the upper limits. Still, I bagged a lot of large animals with a hard cast at slower speeds. Thanks for the post....and thanks Ray B for your correct comments on Sectional Density. ........I am still considering a buffalo hunt in the not too distant future, so like to read how everyone else does it.................FWB
 
I have always thought that the 45-70 could be loaded up to make a fine buff cartridge. This thread shows it can be done, and done well. I have three 45-2.1" guns, but recoil always prevented me from exploring the upper limits. Still, I bagged a lot of large animals with a hard cast at slower speeds. Thanks for the post....and thanks Ray B for your correct comments on Sectional Density. ........I am still considering a buffalo hunt in the not too distant future, so like to read how everyone else does it.................FWB

I've got loads worked up for Beartooth Bullets Piledriver and Piledriver, junior; at 525 and 425 gr respectively. Getting about 1625 fps out of both of them.

My buddy and I are planning a trip to Holy Cross, AK next September for a DIY moose. I want to bring my 9.3x62 (and I still might), but I've got a ton of practice rapid-firing the 45-70 on live critters (can't let a sounder run past me without emptying my 6+1 1895GBL). My buddy just got a 375 Ruger, and he's still getting his sea legs. I figure I have until the day we need to leave to practice and decide which is going with me. But between my buddy and me, I'm the better (and faster) shooter.

If we were going on a guided hunt, I'd probably bring my 6.5x55.
 
I have extreme confidence in the 45/70 people always associate the old black powder velocities with the performance of the new stuff. I used a 1895 Guide Gun.
 

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I have always thought that the 45-70 could be loaded up to make a fine buff cartridge. This thread shows it can be done, and done well. I have three 45-2.1" guns, but recoil always prevented me from exploring the upper limits. Still, I bagged a lot of large animals with a hard cast at slower speeds. Thanks for the post....and thanks Ray B for your correct comments on Sectional Density. ........I am still considering a buffalo hunt in the not too distant future, so like to read how everyone else does it.................FWB
you have probably already seen this but in 2005 i killed an old dagga boy with my scope sighted contender in 45-70,shooting the cor-bon 405 gr penetrator bullet,63 yards,one shot.
mypictures026-1.jpg
 
that's one gnarly old bull!
 
The two on the far right are 425 and 525 gr, respectively. BNH of about 22-23, but not brittle like linotype. I'd risk the money of a cape buff hunt using the one on the right.

bullet_comparison_small.jpg
 
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