contender 45 win

[milltownhunter]

I just got a 45 win I think it is .451 I have 700 rounds of loaded .454 ammo I can get the gun closed would this be safe to shoot or would the 454 ammo give to much pressure

[Hickory]

If you mean that the 45 Winmag is loaded with .454 diameter bullets, you can shoot them "IF" they are not loaded to maximum pressures. And I'm thinking 10% under maximum.

[milltownhunter]

454 diameter

[cainttype]

I hope "454" doesn't mean Casull.... That would be a really BIG "Don't do it!".

[cainttype]

If you are referring only to the diameter of a lead projectile, a regular 45 ACP taper crimp die can "size" the cast down if necessary to fit, but most TC chambers wouldn't be so tight as to need that.
Moderate charges behind a cast projectile shouldn't be a big issue in that scenario. Going several thousandths over bore to fit throats is common practice.