Converting data for jacketed to cast bullet

[roysha]

Is there a general rule that is followed when using jacketed bullet data to load cast bullets and vice-versa? In other words, does one reduce the charge, (or increase as the situation may warrant) and if so, by what percentage?

I finally found some data for the 358 Norma but it is all jacketed bullets and I want to shoot cast.

[bobthenailer]

Lyman 70's vintage cast bullet reloading manual , Data for 358 Norma mag, Norma Brass & rem 91/2 primers

Lyman #358315- 206 gr gc , #2 alloy . Unique powder, 16.0 gr @1604 fps / 21.0 gr @1865 fps
Lyman #358318- 247 gr gc ,# 2 alloy . Unique powder, 15.0 gr @1436 fps / 19.0 gr @ 1658 fps

[roysha]

Thank you. I do have that data. I was looking for something more towards the upper end of the power scale using the Lyman 358009 bullet, which is a nominal 280 grain projectile.

Ideally I could find some 300 grain bullet data, (which I did but it is for jacketed bullets, therefore my question) and use it for a starting point.

[Bwana]

You should have no problems as long as the boolit weight is the same, or nearly so, and as long as the seating depth is not more than the jacketed bullet. The only question I would have is that most of the jacketed data is most likely going to be higher pressure than is usually run with cast boolits.

[Larry Gibson]

roysha

From your previous thread;

I would like to get the loads in the hunting category rather than just a plinking load using pistol powders, something in the 1800-2000 fps range if possible.

Any help would be greatly appreciated.

I'm going to offer some help based on load data from a previous 46th Edition Lyman manual, not based on personal experience.

For the 35 Whelen with the 358009 bullet of 280 gr they list a starting load with 3031 of 39 gr. The max for 3031 is listed as 48.5 gr. If I was going to use 3031 (probably not a bad choice) for that bullet in the 358 Norma I would start at 43 gr and use a 3/4 - 1 gr dacron filler. I would work up in 2 gr increments using 5 shot groups until I reached the target velocity of 1900 - 2000 fps chronographing the test strings. Selecting and acceptable load from that velocity range (if there is one, probably will be) I would then tweek the load +/- 1 gr in both directions and shoot 10 shot test strings to determine accuracy and internal ballistic consistency.

However, my choice of powders would be H4895. I would start at 44 gr, use the same 3/4 1 gr dacron filler and complete the testing as above.

That's how I would develop a load for that heavy cast bullet in the 358 Norma Magnum.

If I wanted to push to higher velocity I would switch to a slower powder such as AA4350 or H4831SC.

Larry Gibson

[badgeredd]

I've been loading my 358 Norma with IMR7828 SSC with good results. I'd suggest a starting load of 70 grains with a 300ish boolit. My final load is a couple grains higher. That'll keep your pressure a little below 40000 PSI and should work well. For my alloy, I've been using a mix of 3 pounds pure lead, 5.5 pounds of COWW and 1/4 pound of #2 (see ROTOMETALS) babbit, water dropped. My average velocity is right at 2350 fps which gives one a little over 3700 foot pounds of energy. I am using my own boolit creation that finishes out at 300 grains. I haven't shot this load any further on paper than 100 yards, but am getting consistent 1 3/4" to 2" groups at 100 yards. BTW, I seat my boolit 0.350 into the case, making the OAL a bit long, which causes the boolit to engrave rather well in my gun.

Basically if you don't have 7828 I'd go to the starting loads for jacketed bullet with the highest loading density, like 4350 or slower powders. My experience with Norma has been with cast boolits to stay around 40,0000 PSI to preclude alloy failure.

Edd