Have a 458 Winchester Mag. Custom 24" King barrel 1:14" twist. Using SR4759 powder. Question is----- What size cast bullet to use with this fast twist? Have tried 300 and 500s seems ok but still not impressed. Looking at all the mould manufacturers can leave one mind boggled. I would like a round nose (no flat point) and has to be gas checked becouse of the higher velocities I may go up to. I do like the Postell by Brooks Moulds but its not gas checked. Any experience greatly appeciated.
Cast bullets / rate of twist
- Thread starter Super Scout
- Start date
Most of the moulds for those heavy .45s are meant for Black Powder cartridge ie: soft lead,plain base. MT Chambers produces 4or 5 bullets of that type as well as 405gr.,465gr.,475gr., .480gr. which are meant for higher vel. and modern guns....they are hard cast and the latter 3 are gas check. Your 1-14" twist should be good with those heavy bullets as 2 of my .45s have 1-18" twists and they stabilize all the Chambers bullets up to 600grains.
Super Scout: 1/14 is faster than the norm for the caliber but it is really not excessively fast for shooting cast. It will help stabilize heavy bullets (500 grain +) at reduced velocities if you are leaning that way for practice. I would speculate that a gas checked bullet cast from wheel weights with 2 % tin added should maintain accuracy to around 1900 FPS without resorting to heat treating the bullet. Oven hardening should get you higher than that.
More important to the discussion is to determine your actual groove diameter in the barrel and also to get a chamber cast done so you can select a bullet that is suited to the throat. You should select a bullet that casts about .002 larger than the groove diameter and that allows the bullet to reach the lands while being well supported in the throat. Some people might suggest using the largest size bullet that will still allow chambering of the loaded round to help maintain alignment even if that is slightly larger then the +.002 originally suggested and let the bore do the down sizing.
Another option is to select a bullet that requires paper patching. Even pure lead bullets can be driven surprisingly fast when patched.
I would be interested in knowing what you finally select as I may have need to acquire a mould for the same cartridge for casting for another person.
More important to the discussion is to determine your actual groove diameter in the barrel and also to get a chamber cast done so you can select a bullet that is suited to the throat. You should select a bullet that casts about .002 larger than the groove diameter and that allows the bullet to reach the lands while being well supported in the throat. Some people might suggest using the largest size bullet that will still allow chambering of the loaded round to help maintain alignment even if that is slightly larger then the +.002 originally suggested and let the bore do the down sizing.
Another option is to select a bullet that requires paper patching. Even pure lead bullets can be driven surprisingly fast when patched.
I would be interested in knowing what you finally select as I may have need to acquire a mould for the same cartridge for casting for another person.
- Location
- The Conservative part of Ontario
The main worries with faster twists, are stabalization, and stripping the lead.
I think you can win out over both by using a gas check, and very hard bullets, then playing with designs, and weights like the rest of us.
I think you can win out over both by using a gas check, and very hard bullets, then playing with designs, and weights like the rest of us.
