Know there's a bunch, and good ones, too.

Here's what I thought the guy will need to order his slugs: any omissions or misinformation are purely my own.

"""Thanks for the reminder on the cast .45-70 slugs for your brother...525gr is his wish?"""

I think the caster would want/need the barrel's throat size, bore slug size, rate of twist, bbl length, and intended powder [black or smokeless type; or both]. Throat length may be a factor. Also. it doesn't sound like he's going to do paper patch, at least for now, but that appears to a factor for the BP long range match folks up at Raton, etc. Articles by Mike Ventorino in Rifle/Handloader magazine are easy reads and he has achieved some wins, so that's a possible source. Also some books are available on the whole subject, if he wants to get into it with some depth.

All the foregoing isn't needed if y'r bro just needs a hook-up and he'll take it from there, but at some point a custom caster will want the info so the bullet is a match for gun. Having the info ready will be a plus, then. If he's just gonna plonk big lead on rocks, mebbe none of it is needed, but consider y'r bro built barrels for Apex, he may wish to go for precision.

Thanks All,