Thanks Dave.

You have dispelled this idiotic supposition.

Do you want to send a link to these pages to Garrett or should I?

---Catter

RAB,

I cann�t predict but try to guess from my experiments and calculate from a simplified theoretical model:

300grs/2750fps shows less than 10 % more penetration over 270grs/2900fps.

This finding reflects the observation of hunters, that less weight normally can not compensated by more velocity in safe pressure limits.

But if you add another 150 fps, the 270grs/3050fps will equal the 300grs/2750fps.

Accordingly the 350grs/2550fps will have another 8 - 10 % more penetration.

But as you said: "Impact medium and bullet characteristics are too complex for all inclusive formulae..." , so the above is likely in water. But in wood we may observe a contribution to the drag from the additional friction of the longer shank of the heavier bullets.
So at the end for those small differences we are doing number crunching with not too much meaning for the practice.

Norbert,
You are a beam of sunlight in the darkness. Much appreciated.

"and the 250 fps increase from 2150 to 2400 fps gains 6 inches" , 470MBOGE from what you saw and said here there is not a great gain of penetration between 2150-2400.It looks like that would help to keep down the recoil somewhat at 2150 or 2200fps and still get about the same penetration?,Kev

My own most impressive observation is that a .710 flat nose, 1000 gr Bridger at 3000fps will out penetrate anything short of a Artillery. I have quit trying to find the damn things as they go thru all my OAK logs and I have to dig for 15 minutes to find them in the dirt behind the logs! The 470 MBOGO with solids and similar bullets is next. I'll bet $1000 that NO GARRET 45/70 LOAD KNown to MAN can beat either of these rifles for penetration in ANY MEDIUM!-Rob

HI,

Good point 500grains,the 4570 is a great round but I to think it is a little to slow.That is one reason I went with the 50-110,but still it is limited in its range. Kev

Interesting posts, so Weatherby with the introduction of the .460 was not off base, if there were bullets which could hold up in those days.

So on a general basis, for example buffalo hunting, loading a .450 cal to 2450 fps with a 500 gr bullet (SD about .3 ), should be about equal in penetration to a .500 cal at 2250-2300 fps with a 570 gr bullet, again with a SD of about .3. Solids only. ?????

But now if you were shooting softs, like a Woodleigh, aren't their limit about 2250 fps or there abouts? Actually, I use A-frames for the .450 and have shot buffalo and they have held up.

Would shooting softs at different calibers and velocities into water jugs serve as a "Go No Go" test to see if the bullet will keep from early fragmentation?

Years ago a buddy and I constructed a test similar to 470 Mbogo, only with wet newspaper separated every 12 inches by thin plywood. We found out that the bullets seemed to wander and one shot seemed to damage the media for the next shot. A lot of work and little recoverable data except we could see the expansion characteristics of the softs.

So really appreciate Dave's hard work to construct probably the best repeatable experiment, one that could never be repeated at the local gun range.

Good Shooting! pm

HI,

I also would like to thank 470 MBOGO he went to alot of work to get this information,great job. Kev

HI Kev
The extra 6 inches of penetration as mentioned is in hard plywood and is significant. The other bonus is trajectory and as far as recoil at that point it doesn't really seem to make a lot of difference. Your into a recoil stage and the extra ft. lbs. is just there. You would notice a really big jump between the 1550 fps load and the 2400 fps load but between the 2150 fps and the 2400 fps it seems that there is less of a significant difference.

I'm thinking about testing the 500 grain Bridgers starting at 2100 fps and going in 100 fps increments up to 2600fps to see if there is a drop off in penetration which I doubt. I'm also thinking about trying it with some quality soft points such as the Barnes X and the Swift A-Frames to see if there is a difference in the results from the solids. I don't mean in actual depth of penetration but how the relationship between velocity and depth of penetration is. To find out if high velocity and heavy bullet upset is detrimental to penetration compared to the Barmes X type of expansion. I think the Barnes and the A-Frame represent the two ends of the scale in soft point bullets. One being minimum expansion with maximum depth and the other being maximum expansion with good depth. Both being of the highest quality for reliability and weight retention in the soft point expanding bullet range. Once I reach 2500 fps with the Swift A-Frame in plywood I will be able to relate at least to myself what that represents in Buffalo penetration. Should be interesting. One has to keep in mind that all of this is a comparrison with as many things being equal as possible.


Take good care,
Dave

Dave,

If your interested, I'll send you down a half dozen 45/70 cartridges, loaded with that 550 gr hardcast bullet. You can use them to "benchmark" your 470's penetration!

Cheers,
Canuck

HI,

Thanks for the follow up 470Mbogo, that is why I put that line about the 6 inch differents as it seemed that way to me also. I would love to try a test like yours with my 50-110 win 86,I have chron my 525 gain WFN HC at 2200fps. I am also going to get some 550WFNHC and I should get 2100-2150 fps.I am thinking about a 570 grain HC that I have cast myself,but I am not sure about 2100fps,maybe 2050 fps. I really would not want to get below 2100 fps. Thanks,Kev

For penetration tests one can use cardboard boxes, lined with trash bags, filled with water.

I agree 100% as will anyone who has hunted, velocity up to a point is great for penitration, I do believe however like most things one can go overboard with velocity and then funny things start happening like bullet integrity and off course bullets, but thats starts at very high velocity....I still adhere to 2350 to 2700 FPS as ideal in big bores and a 45 cal at 2150 is no slouch on live stuff, and 2350 is even better...

Buffalo, elephant and whatnot are not built of plywood and any 40 cal or larger at 2100 FPS is a capable round and has been proving that for eons...Plywood is a good comparison substance for testing bullet construction and is easy on bullets, but dry magazines will destroy all but the toughest of bullets.

I have not noticed the Flat Nose penitrated more than the round nose solid on game as both penetrate enough, always seemed about the same but who knows!! The FN does travel in a direct course where ocasionally a RN will slip off a bone at an angle...

The main thing about a flat nose solid is that it cuts a wadcutter type hole that will not close up or plug with fat going in or coming out and it lets out a stream of blood, and like a volkswagon, canned milk or a Lonestar beer, buffalo die when they run out of liquid....The FN solid also does a lot more damage internally than a RN....also the cutting shoulder grabs a lot of smaller blood vessels I think.

Hi Canuck,
That would be great if you could send some down. Send them with the arrow shafts and I'll fletch them up for you.
Hi Kev,
You should make out really well with your rifle and cartridge. The main thing about the testing is that you can see by the penetration result that 2150 works well, 2400 works better but 1550 is short by a bunch for deep penetration comparrisons with real big bore African cartridges. The 45/70 is an awesome cartridge in itself and is a very hard hitting round but with limitations (trajectory). I shot a nice blacktail deer with mine this season and the results were very good. With the Remington 405 grain bullet with a straight on frontal chest shot the bullet penetrated to just ahead of the hind quarters which would represent approximately 28 inches of penetration. This is enough for North American hunting and being a 45 caliber needless to say I didn't have to look for the Deer. Your cartridge with a heavier bullet, higher velocity and a larger diameter should be very impressive to say the least.
Take good care,
Dave

I agree 100% as will anyone who has hunted, velocity up to a point is great for penitration, I do believe however like most things one can go overboard with velocity and then funny things start happening like bullet integrity and off course bullets, but thats starts at very high velocity....I still adhere to 2350 to 2700 FPS as ideal in big bores and a 45 cal at 2150 is no slouch on live stuff, and 2350 is even better...

Hi Ray
You have come over to the dark side. You usually put the brakes on at 2400 fps.
Take care,
Dave

Dave,

Do you think if the penetration tests were done in animal type tissue that the 550 grain 45/70 would show up different as compared to the higher velocity big bores.

Mike

Dave... I am making a 500a-2. Have you tried the flats in the 500a-2? What good and bad points does the 500a2 have over your Mb470?

Hi MIke,
I think that in tissue the 550 hard cast bullet MIGHT penetrate deep enough but the higher velocity big bores are going to penetrate a lot better, deeper and cause more internal disruption probably with the same relationship that the plywood testing shows. At 2150 to 2400 you would be gauranteed the penetration is there whether you hit bone or not. If your talking about Buffalo you could be certain that a second shot from the rear will reach the vitals. I don't think that 1550fps could make any such gaurantees. The 2400 fps with good sectional density has proved many end to end penetrations on Buffalo. Keep in mind that the shots in the tests were point blank so if you had to allow for sixty to 100 yards that 1550 would probably be down into the 1200 fps (aprox without looking it up). That's why personally I like the higher velocity.
Take care,
Dave

HI Smallfry,
The 500 A-Square is an awesome cartridge. If you want to use it to it's full potential recoil is the only disadvantage. So either you end up with a very heavy rifle to lower the recoil or you end up with a muzzle brake. The 470 is a more shootable cartridge due to the fact the bullet is 100 grains less but still heavy enough. Both cartridges will give deep penetration and awesome performance. It's back to recoil. Lots of people that try my 470 will shoot it quite a few times but with my 500 A-Square they only want to try it a couple of times. My 500 is 10.5 lbs without a muzzle brake so is a very practicle hunting rifle that is packable. What are you building your 500 on?
Take care,
Dave

Dave, My 500 is going to be on a CZ550. It will not have a brake on it, and depending on how well it balances out, I would like it to weigh around 10.5lbs. I am no stranger to recoil, however, my original intent has been to use it at 2150-2200 there abouts. Of course, I will probably play with it all the way upto 2400. If I cant rip 3 good quickies off (which I doubt at 2400) ill stay around 2150. As some already know, I am one of the smaller gents on this forum, though I bench almost twice my weight and am in great shape. Where I have limitations in recoil is... poorly designed (painful) stocks, and physics. Its not just that I start to take a step back during recoil, but recovery on succesive shots becomes slow, something that is important to me.

Hi smallfry,
It sounds like you've got it all figured out 2150 fps is the 500 Nitro and can do it all for sure. When you go to 50 caliber at 600 grain bullet at 2250 is pretty impressive. Look into the F990 pad to help with the recoil and look for a stock such as the McMillan that has a decent butt area and straight lines if your thinking synthetic or fiberglass.
Take good care,
Dave

I ve read 2400 fps is the optimum penetration speed.Thats not to say the same bullet fired at 3000fps would not penetrate more but it would be of diminishing return.Thesame rifle fireing that 3000fps round would penetrate better with a heavier bullet at below the 2400fps mark.I ve always believed that assertion,but have no proof.thoughts?

Unfortunately, it is not that simple. The quick answer is, the optimum velocity for maximum penetration is a function of the bullet design!

For example. Lets say you fire a .585", 650gr Woodleigh into cinder blocks at 2400 fps, it may well explode on impact! Now if you shot a bronze solid, .585", 650 gr bullet into those same cinder blocks at 2400 fps, penetration would be MUCh better than with the Woodleigh soft point.

Scott

Hi hammerhodder,
I'm really curious about that very fact. I mentioned in an ealier post that I want to load 500 grain bullets starting at either 1900 fps or 2000 fps and go up in 100 fps increments to 2700 fps checking the penetration depths and then putting them and the recoil energies on a graph. It will take some time to do the reloading for velocities etc but it will happen this Spring. I hope to get a bunch of the Bridger 500 grain solids with the big .410 meplate.
Take good care,
Dave

Follow the link. It is an interesting dissertation on armor penetration. The physics is the same for bronze penetrator / wood planks.

Armor penetration formulii

Scott

Hi Scott,
Interesting link but I kind of like the shoot and measure system to keep things simple. I think testing this way will make more sense for the average guy with the same curiosities. I have a tendancy to get lost in all the jargin and formulas so try to stay to the KISS system.
Take care,
Dave

Dave,



Just providing a little technical mumbo jumbo to support your test observations. I too am interested in your research, and look forward to reading about your results.



I have been contemplating performing a similar study, but with soft point bullets. To be worthwhile though I really think I will need ballistic geletin and bone. Of course if I could find a bunch of post sell date bone in hams I would be in business. Would be messy, but as close to the real thing as possible.



Scott

Mbogo 470,

Nope, I have not come over to the dark side, I simply realize that the monolithic bullet has changed the scheme of things considerably, the old voo doos don't apply to them....

I still hold with 2400 FPS with all the soft nose traditional bulleta even in the premium varity...but it is bloody hard to destroy a monolithic solid under any conditions, although it can and does happen on extremely rare ocassions...

Dave,

Thanks for your research. While plywood may not an ideal testing medium, it's useful information nonetheless.
Until they let you shoot 'mad' cows, it will have to do.

George

I'm probably as big a fan of the 45-70 as anybody. I have gotten some strong reactions saying that a 45-70, shooting Elmer Keith's load will take any soft skinned game on this planet. No I don't hunt brownies with it. In a strong rifle, it's not your father's 45-70. That said, it's still not a 458 win mag. It will never out penetrate the bigger faster cartridges I accept the fact that the cartridge has it's limitations. On the plus side it can be used in a light, fast handling rifle that shoot relatively inexpensive ammunition.

Dave

Hi Scott,
I mentioned that I was going to do the same tests with both the Swift A-Frame and the Barnes X bullets. It should prove to be very interesting.
Hi Ray,
I think you'll find with the top quality bullets that you'll still be in the Dark Side realm. Time and some test will be interesting don't you think. The 500 A-Frames at 2500 fps came out picture perfect and I can't see why another 100 fps or so would change that. Not that I want to be there but I sure like the 2500 fps mark. Considering the distance you want to shoot Buffalo at it gives you an impact velocity of 2400 fps

470,
I don't doubt that your correct, and 100 to 200 FPS makes litttle difference beyond 2200 FPS, one way or the other to me..I suspect either will work...

Dave,

I read that, and I anxiously await your results. My only concern is that the hardness/stiffness of the plywood test media will upset the soft point far quicker than animal tissue (how much quicker ???) and lead to much lower penetration numbers than actual field experience will exhibit.

I guess I am anally retentive about over-penetration and it's potentially dire circumstances. It is a pet peeve of mine, so please bare with me.

Scott

Hi Scott,
You have to keep in mind that it's a comparrisson test and of course it will be different in animal tissue but probably with the same results. I know that the Swift A-Frame penetrated on a straight on chest shot all the way to the hind quarters on a Buffalo (aprox 52 to 58 inches) With a starting velocity of 2500 fps and an impact velocity of around 2350 to 2370 fps so it will have a coressponding plywood penetration depth during the plywood test. That bullet ended up merasuring .875 across the front. I don't think that the Swift will get any larger than that. The plywood may make it shed more weight from the friction. I'm going to gather as much info as possible as far as penetration depth, bullet weight, expansion and velocity for each shot as well as the recoil generated. If John at Bridger can send me bullets the same info will be listed for the solids and softs.
Take care,
Dave

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