michael458 said, "I used a 458 Lott on the first 4 elephants and my 50 B&M for the

last two. When I go for elephant again I will be using my new 500 MDM." I've never

heard of these calibers and I am hoping Michael will give details here, starting with

are they flanged/rimmed, belted, rimless, rebated rim? I look forward to the info.

Hey Jack

I will be happy to give you some details about each. In 2005 I felt the need for a smaller, shorter, lighter, more handy big bore rifle than my standard doings with Winchester M70s 458 Lott and so forth with 24 inch barrels. My first thoughts were to just shorten the barrels on some of my Winchesters-which I did. However in the basic belted case you start loosing lot's of performance with shorter barrels, but it is still enough to do the job no doubt.

A friend of mine was interested in .500 caliber rifle, basically a 500 SW in a lever gun. This got me to thinking about a WSM bolt gun and this is when I discovered the 300 RUM brass was good for something besides 30 cal. What I ended up with is a 2.25 inch case cut from RUM brass and .500 caliber bullets fit in it perfectly! So I went to work on this. Along with SSK Industries who builds all my rifles, we also developed some very fine bullets for .500 caliber. This is not .510 caliber--true .500.

I call it the 50 B&M. It is a Winchester M70 WSM action standard with 18 inch barrel which is optimum for this cartridge, more barrel does not give you much more in velocity, and the gain is not worth the effort, to me. The case is very equal to 458 Winchester case capacity. We have excellent solids for this gun at 510 grs and the 18 inch tube can run them to 2100 fps and stay well under pressure limits. I used one of these in Zim in 2007 for 2 bull elephants and 5 cape buffalo and it was a grand success to me. Penetration and performance was very much on par with any 458 Lott I had ever used, and increase in caliber made up for a good bit. In addition to the 510 Solid we also various expanding hollow points with 6 petals in 380 gr--426 gr and 470 gr. I used a 426 at 2250 on a buff, light for caliber but penetration was good and equaled a dead buff. For that sort of work I rather have the 470 version, which I used on griz last year with great success. Penetration of the 510 Solid is fantastic, equal too, better in some cases than a 500 458 caliber solid-very much designed near the barnes fn. I was very happy with it's performance, for one elephant a frontal brain shot was taken, it traversed the entire skull, out the back of the brain, lost in the body somewhere. The second elephant was a broadside shot at 40 yds the bullet exited, a second shot from the rear traversed 7 ft of elephant and exited the front of the chest-two big .500 caliber holes criss crossed the heart.

It was a simple matter to take the basic 2.25 inch case and start going down-458 B&M and 416 B&M. The 458 and 416 started off with 20 inch barrels. The 458 version is a dead equal to good handloads in 458 Winchester, in other words 500s at 2150-450s at 2250 fps. I have even now gone to 18 inch barrels on the 458 and lost very very little to no performance. The 416 B&M with 20 inch barrels is capable of 400s at over 2350 fps-350s at 2450 fps and 300s at 2650 fps. I now have 1 18 inch 416 B&M and in some loads it looses as much as 60-70 fps for the 2 inches, other loads it shows very little loss. For me I will sacrifice that velocity for the shortness of the rifle. But the 416 B&M is truly best at 20 inches.

I could sit and explain all day long and show photos of the rifles, but until one actually lays hands on it is hard to understand how handy these guns are. Depending on whether wood or synthetic stocks, they come in at 6.5 to 7.5 lbs--the rifles with 18 inch barrels have an overall length of 38 inches. All of the rifles are built on Winchester M70 classic, or control feed. These are all WSM actions. Big performance in a small package. I am sad to report that these guns are so good at what they do, and they carry, handle and feel so right, that all my various 416s-458s-470s Winchesters with the long barrels have been retired permanently. While I get one out from time to time and admire the rifles, they don't go to the field any longer.

Now to step up business, I have turned into a .500 caliber nut case. I have small ones, medium ones, lever gun .500s so why not have a long action Winchester M70? I took the full length RUM case trimmed to 2.8 inches, used Winchester M70s that were chambered in 300 Ultra, snatched the barrel off threw it in the trash and put a 21 inch .500 caliber barrel on and go to work. 500 MDM (my initials). I had some issues at first with the Super Grade stock--busted twice, first time after 18 rounds of the 1st generation loads, second time after repaired 4 rds. I sent the rifle to Accurate Innovations and we put a AAA Myrtle Stock together for it. AI has that neat little aluminum chassis that the action sits in and has solved all issues with the stock, and looks damn good too! I just finished load development with some of the bullets I intend to use in these rifles. A 550 gr Solid exactly like the 510 that has been so good, the 510 of course, the 470 HP and the 426 HP. Currently I am up to 2210 fps with the 550 gr solid--2320 fps with the 510 gr Solid--2420 fps with the 470 HP and over 2500 fps with the 426 HP. Because of bore diameter and efficiency of the cartridge I am able to use a 21 inch barrel. Winchester M70 at 8.5 lbs with the Myrtle stock.

Other cartridges is the 50 B&M Super Short--any WSM case cut/trimmed to 1.65 inches--.500 caliber-Winchester M70 WSSM rifles with 16 inch barrels, Winchester Ultimate stocks at 36 inches overall, and 6.25 lbs. Fine little guns capable of 500 gr bullets at 1725 fps--450s at 1850 fps--400s at 1950 fps--375-385 gr bullets at 2150 fps-325s at 2300 fps and playing with the new Hornady 300 gr bullet at 2430 fps. This is not a gun for the heavies, but boy it sure is fun and a hammer on lesser critters, like hogs and such.

50 B&M Alaskan--Win M71s or Marlin Guide guns with 18 inch barrels. Simple, squeeze a 50 Alaskan (.510) down to .500 caliber. I am shooting a 500 Hornady at 2000 fps. Its a hammer for a lever gun.

The last of the B&M series-the 2.25 inch RUM case is the 9.3 B&M which is in the works right now, rifle being built. I am somewhat taken with 9.3 caliber right now, new and different to me and I need a project. So once again Winchester M70 WSM action with 20 inch barrel. Should be a great small caliber addition to my series.

Dies are available for all the rifles, most I have or SSK has on hand (no waiting) from RCBS and Hornady. Right now I like the Hornady dies a lot and they are far less expensive. Proper head stamped brass is available for all the B&M series and the 500 MDM, and in some cases on hand.

The key to the B&M series rifles and cartridges is the entire package-cartridges are good, very good, but combine them with the rifle, now you have something! Short, handy, fast, easy to carry all day, recoil is less and no more than most any other big bores, all the advantages and no downsides. Many of us have been in the bush all day with that fine big bore rifle that comes in at 10-11 lbs, 24 inch barrel, long and cumbersome, and by mid day thinking this thing is getting bigger by the minute and heavier! Not for me anymore, it is unbelievable how easy these are to carry all day, day in, and day out, and when the time comes to go to work, they do the job!

That's my spill. God knows I love'em, so please if anyone has questions ask away, I could go on all day long about them!
Thanks

Michael

Hi michael458,
What barrel twist rates and contours are you using on all the various B&M and MDM wildcats?

Caliber-by-caliber breakdown please.

And please insert some more elephant hunting exploits, detailing penetration/bullet performance ... just so this thread does not get accused of being "OT."

RIP

Why you have to ask all these hard questions????

OK, then, will do my best. On the .500 caliber guns the first ones we went with a 1:18 twist and .820 diameter barrel at the muzzle. This was accurate, shot extremely well with all bullets. However when I started working with our various solids I soon learned that 1:18 would not stabilize the RN solids during terminal performance. So we quickly did two things-we threw together a barrel with 1:12 twist rate and penetration improved drastically with the RN bullets. In fact they were stable now to 90% of the total penetration before going off course. Before only about 50%. Then we redesigned the bullets and gave them meplats from .300 to .350 penetration increased tremendously and was 100% dead straight penetration.

Now I still wanted to shave some weight off the guns, although .820 at the muzzle handled well, and was plenty stiff, I dropped it to .785 on all the .500 caliber guns, even the new 500 MDM. This made a big difference in weight. I think I dropped 3/4-1 lb doing this. Which put me where I wanted to be with them.

The 458 B&M I think is 1:14 twist, and to be honest I am not sure what the 416 B&M is. I leave that up to JD. The 458 and 416 are .760 at the muzzle.

On all my rifles I like that NECG barrel band front sight, so sometimes I have to stay with a barrel diameter that will fit one of those! I like them, I think they add a lot of class to the rifle.

Well I wish I could tell you more about elephant and bullet penetration with my B&M series, but if I did it would be a damn lie, since so far I have only shot the two elephants with the 50! Since I am not prone to doing such things, I can move on to some other african critters and bullets. I think that might be ok, because Jack didn't ask specifically about elephant and asked more about details of the rifles and cartridges.

In 2006 I went on a 5 day test mission with the first prototype 50, and at that time using only the available .500 caliber bullets, and a couple of our first run of solids. Without a recount I think I shot 15 animals including impala, kudu, zebra, wildebeast, giraffe, hartebeast, and eland. Some multiples, zebra X2, widlebeast X3 and so forth. I had already done quite a bit of terminal test work before hand, so I did not run these bullets faster than what they could handle. I tested everything from 375 Barnes X-385 Remington Bonded, 400 Sierras, a 409 RN solid we began with, and the 500 Hornady. Everything worked proper and actually exceeded my expectations. I expected animal reactions somewhat better than what I had observed with various 45/70s. What I got was animals that reacted more like they were being hit with higher velocity 458 Lott loads! Many of these dropped on the spot, and that's just not all that common with wildebeast and zebra! Of course the impalas never took a step, but an impala ain't no zebra! Even my wife noticed the difference in what she had observed in the past. I have only shot two giraffe, one with a 45/70 and 460 Cast Performance at 1750 fps and one with the 50 and a 500 Hornady at 2000 fps. Well the one with the 45/70 was a running gun battle and 4 properly placed big cast bullets, and finally solve the problem! With the 50 and the 500 Hornady it was a 10 yard gun battle, and another round was not needed. OK, I was beginning to be rather pleased with the .500s! Not to forget how short and handy they are! The work I did with the little 409 gr Round Nose solid was very dreadful. I backed everything up with them, just like if I were hunting buff. After all, this was a test mission, and it was possible to have bullet failures, so backup with solids! These damn things, combination of 1:18 twist, and ROUND NOSE-they were more than likely enter the right side and do a U turn and come back at you! OK, it was not quite that bad, but it was close at times. I watched one hit an eland and do a 90 and come out the top! I have to say it was a little embarrassing at times! I don't think I got one straight line penetration from them the entire trip! Back to the drawing board, 1:12 twist and FLAT NOSE PROFILE.

We sorted out the solid issue without doubt, with a couple different designs. Now I must go for a bit, but I have not made it to the new design bullets on buffalo! Well maybe next time I can get to that, if anyone has any interest at all.

Thanks for the interest RIP, appreciate it.

Michael

michael458,
Ah, yes, good choices on twist and muzzle diameter for the 50 and 500.
And proven reasons by your field experience to go with a faster twist!
Also the convenience of the sporter contour with .827" or less muzzle diameter to get a standard barrel band to fit for the front sight!

So you are down to about a 5A or 6 sporter contour ... shortened, compact and handy.
I really prefer a rifle barrel in the 23" to 26" range. Cannot get on the shorty bandwagon.

I am going to go with a No. 6 sporter contour and a 1:9" twist for 500 Mbogo No.2.
That ought to be about .770" when cut back to 24" using the standard Pac-Nor contour.
And they offer the 1:9" twist as a standard offering for .510-caliber also.

Inside of 500 yards you cannot have too much twist, if you are using tough bullets at whatever velocity, high or low.

I am hoping to prove the 1:9" twist 500 Mbogo with .510-caliber/570-grain GSC FN solid at 2500 fps:

The simultaneous "Texas Heart&Brain Shot" on Jumbo, one shot kills from any angle on elephant.

Wildcatting is cool.
Just ask Saeed.
He likes to keep his .375/404 Jeffery chamber and brass specs secret.

Hey RIP
Thanks. While the slower 1:18 twist did well as for accuracy with solids and expanding bullets, and had no effect on expanding bullets during terminal performance, it would just not stabilize the solids during terminal penetration. However, once I had the prototype Flat Nose solid designs this even took the 1:18 twist to 85-90% straight line penetration, even though the twist is not optimum! Flat nose design shows another "twist" so to speak, pun intended!

Currently all the .500s come in at .785 at the muzzle. I am without doubt a big supporter of short and compact. I will sacrifice a lot to get short and handy, but with the B&M series, and the 500 MDM I don't have to sacrifice much if anything! The same would be true for Jeffes AR series, although he is burning a bit more powder and probably would start loosing some below 20 inches. Must one day get your hands on one to see what I mean.

1:9? Well as I understand it, how can you "over stabilize" a bullet? Under yes--Over???

All my barrels are Pac-Nor, I am EXTREMELY pleased with them!

As for 500 yds, well I can't see that far anyway! So I keep things close if possible.

A .510 caliber 570 gr bullet at 2500 fps is about more fun than I can stand I think. Of course lot's depend on weight of the rifle, stock and what have you! I am about topped out with the 500 MDM and the 550 at 2200 fps, but it weighs 8.5 lbs.

Wildcatting is way past the cool part, it keeps me busy and fired up all the time. My problem is that I can't get much interested in the small stuff or I could have more to do. One example is that I built a 264 WSSM--have not much got past the 1st or 2cd generation load data before getting bored with it. I have not even picked it up in a year now! No interest! But put me on a .500 project and I will do 5-7 generations of load data on 4 different bullets, with 10 different powders in a week and be off and running with it!

Michael