I need help with a load development

[crustyrusty]

I am building a second 7mm br rifle and Its only shooting 145gr sil gc lead rounds. i need suggestions for twist rates, and powder selections that will fill the case but deliver 2000 to 2100 fps.. I thought of IMR 4350. but is there any outside programming or data that helps a shooter in this kind of situation? I have plenty of time before this actually happens as I have two rifles to complete before this one gets there.. but it was on my mind and i was wondering,,,, this gun will do 2 things paper punch and deer hunt to 100 yards if this topic is a no no let me know and I will delete it Rusty

 

[riflewoman]

I’d look more in the direction of IMR 4227, and Accurate 5744.

Also over at https://www.castboolits.gunloads.com/ you might find some more experience than here perhaps. But this question is as welcome here as there.

 

[Lone Hunter]

Haven't loaded lead in many years but does sil gc mean gas check? Was wondering if that's what it meant to push them to 2000-2100 fps .

 

[1911nut]

This is some information:

http://castboolits.gunloads.com/showthread.php?68131-7mm-Benchrest-Cast-Data

 

[crustyrusty]

Haven't loaded lead in many years but does sil gc mean gas check? Was wondering if that's what it meant to push them to 2000-2100 fps .

sil is short for silhouette and gc is for gas check

 

[crustyrusty]

what I want is full case density and velocity averaging 2000-2100 fps all the qualities needed to sustain the best accuracy.. Now I shot this same bullet out of my 280 Rem and at that time I had access to a chronograph .. all of the loads that were available were Lyman loads and no mater what load i used accuracy was just average.. now mind you this was in 1989. when I was just married and had a new baby to take care of. so my father-in-law suggested to go in the opposite way use a really slow burning powder and chronograph the loads.I remember using IMR 4831 but the grain not so much but that 145gr SIL GC lead bullet printed 1/2 at 50 yards the velocity was somewhere at 2000 fps.. so I know the 280 case dwarfs the 7mm BR case and that is why I think a slow powder will work better than a fast burn low density charge comments?

 

[crustyrusty]

This is some information:

http://castboolits.gunloads.com/showthread.php?68131-7mm-Benchrest-Cast-Data

that is a cool site!!!