Load info for 345gr 45-70 ?

[xring1]

A friend cast up some 345gr HP's for me. I need load data for them.
 I have a bunch of IMR3031 I would like to use up.
 All the load data I can find for bullets that are close in weight is either for jacketed bullets or the data jumps from 300gr to 405 gr.
 I do have Goex FF but would like to try the IMR .
 The rifle is a H&R SB2 and from  what I have read will handle some pretty stout loads but I am looking for accurate loads for hunting deer.
 Any suggestions ??

[twoshooter]

Anywhere from 30 to 40 gr of 3031 will be just fine, whatever is most accurate in your gun. The top end of that would be at 16K psi, and factory ammo is around 28K psi

[keith44]

twoshooter's loads are safe, but may be leaving something on the table...


What alloy, and what lube were used?

[xring1]

Anywhere from 30 to 40 gr of 3031 will be just fine, whatever is most accurate in your gun. The top end of that would be at 16K psi, and factory ammo is around 28K psi

 Thanks for the info. I have already run some factory Black Hills 405gr at about 1250fps in the rifle and it shoots good

[twoshooter]

What Keith said is accurate. About 36-37 gr of 3031 should duplicate the Black Hills load you mentioned. You could safely shoot 40-50 gr, but somewhere in that range you will begin to notice the recoil, and bullet lube and alloy do become important as you begin shoving them fast enough to maybe pick up leading in  the barrel if they are really soft or not well lubed. What I posted is a good place to start, not where you will end.