I finaly got my new barrel for my CZ swithbarrel. I found some cheap Magtech BMG M33 Ball bullets, 695grain, that I thought that I use for fireforming the 460 Norma brass.

Does any of you have a starting load for this bullet that could be used for fireforming? I have Vihtavuori powders only...

There is data for N560 on the Accuratereloading pages, but this is for a 700grains Barnes SP bullet. 126 grain for 2346 fps. This seems to be a max load. Perhaps a 110 grain load would be ok to start with for the BMG bullet? Or could I go even lower, perhaps 100grain? (Dont want to get too much recoil the first shoot!!)

Any ideas would be appreciated. Thanks!

I started with 100 grains of IMR 4350 with the 668 grain ball and found that 110 grains was perfect, very accurate, and that load works well with 705 and 750 grain target bullets as well, no pressure problems in my 10" twist McGowen Wunder Barrels.

N560 is considerably slower than IMR 4350. Your plan sounds very sound. 110 should not be a max load with the 695 grainers, but you probably out to start with 100 grains and shoot three shots with each 1 or two grain increment going up and watch the velocity.

If I were doing it again, I would start with 100 grains of H4350 Extreme and watch for the sweet spot in accuracy and velocity around 2200 to 2300 fps with 695 grainers in 23" to 27" barrels.

What length and twist is your barrel? You might be able to go faster than I do.

BTW, those loads for Mitch's 500A2 that you are talking about are HOT!!!

I believe the standard 500 A2 freebore is 0.4000" of parallel sided freebore with freebore diameter 0.5110", and 1.5 degree leade. That works fine with the military ball crimped.

One of mine has freebore of 0.3000" length and one had 0.5870" freebore length (same 0.5110" diameter freebore), the latter for use with Hornady A-Max bullets seated out to 4.756" COL.

My above loads work fine in all these freebores, standard, short, and long.

Great, thanks.
Barrel is 25" and twist is 1:18.

Your slower twist barrel is supposed to give lower pressures than Mine Wunder Barrel by McGowen. You will probably get better accuracy at your top end of velocity.

Please report back on your accuracy and velocities.

Cases can be fire formed without a "bullet". For a case the size of the A2, load 16-18gr of Red Dot and then fill case with cornmeal pressed down and topped with a small piece of tissue or even a foam peanut fragment. The topping is just to lessen the chance of knocking some of the corn meal out of the case and into the action. Also, it is best to fire them with the muzzel angled upward for the same reason. These loads will need to be fired at where ever you can normally shoot, as they are noisey. I have used this meathod many times, works great for me. It can also be used to expand case mouths, I even tried this with 300Wby-458Lott, with less powder for that size case.

Hog Killer

Agree with previous post, can form with no bullet - I anneal the 460 wby case, clean thoroughly and load 15 grains of green dot, tamp with cornmeal, and seal with wax - loud pop and nearly complete forming -- also, a fun way to have friends shoot the a2 for the first time and understand that they really are flinching for no good reason.......

Guys its a belted magnum. Nothing special is needed! All you have to do is run .460 wby brass through a 500 a2 expanding die, pick a basic load and seat a suitable .510 bullet. Shoot it and out pops a perfect .500a2 period! I usually just use my std .500a2 load with new brass.-Rob

quote:

Originally posted by Robgunbuilder:
Guys its a belted magnum. Nothing special is needed! All you have to do is run .460 wby brass through a 500 a2 expanding die, pick a basic load and seat a suitable .510 bullet. Shoot it and out pops a perfect .500a2 period! I usually just use my std .500a2 load with new brass.-Rob

Now, THAT makes sence to me!!

I got some Quickload data and a 100grain load of N160 should produce about 47000PSI with the 695grain ball so this will be my first shoot! If the case ends up all black I will increase the load till it looks to be enough pressure. If I can take the recoil...

quote:

Originally posted by Robgunbuilder:
Guys its a belted magnum. Nothing special is needed! All you have to do is run .460 wby brass through a 500 a2 expanding die, pick a basic load and seat a suitable .510 bullet. Shoot it and out pops a perfect .500a2 period! I usually just use my std .500a2 load with new brass.-Rob

I tried this a few times for my 510 Wells and forcing the 460 neck over the 510 mandrel resulted in "wrinkled" and uneven necks. The best method is to do as described earlier in this thread, make blanks with fast pistol powder and filler.

Try some case lube on the inside of the case neck. It won't wrinkle! Save the fireforming for something that needs it unless you just like making noise!-Rob

My smith made a tapered mandrel so I can size the neck really "easy", from 460 to 510 so this is not an issue. I just needed some info about how litle powder I could use safely. I still havent fired it though...

But some good news, the Redding dies is at the customs and I will pick them up today!

I prefer Rob's approach.
I like to get some practice in while fireforming.
Just seating a boat-tailed 35 cent milsurp bullet into the .460 Wby brass necks it up, and yes, a little lube can help there too, and the full charge of 110 grains of IMR-4350 is my fireforming and final load.

There is very little difference either way.

As I said, next time, I will start over with 100 grains of H4350 Extreme and work up with 650 to 750 grain bullets.

With 750 grain Hornady A-Max bullets, 2150 fps in the 23" barrel, and 2250 fps with the 27" barrel is as fast as I want to go with my 10" twist.

The fast twist and modest velocity works well on the heavy bullets, and the accuracy with the 705 grain "Harlow" by AAA Ammo is amazing.

Now, onward to the .510 Gibbs, even closer to a mini-BMG.

I fired the one round yesterday and the case came out pretty good. It was a surprise to me that the neck is shorter now. 100grains N160 and 695 grains Ball. A few more grains wont hurt I think. The recoil was very modest. I was expecting something horridius with the heavy bullet but I guess the welocity was so low there was no recoil.

If there is time I will do some velocity meassurments on saturday. I loaded up to 106grain N160. Best powder according to Quick Load is N550. I will try that the second shoot for my cases. (I only have 15 cases...)