.451 or .452?

[Rem 700]

I just picked up a Bersa 45 Thunder Ultra Compact Pro Pistol and I am new to handgun reloading. I noticed that there are two diameters offered for the 45 (.451 and .452). What factors determine which diameter is needed? Also, I have read that it is important to shoot jacketed bullets rather than lead out of this gun because of the polygonal rifling. Any thoughts on that?
Thanks.[/code]

 

[FOTIS]

Same deal as the 357 mag. Some are .357 and some are .358 (the lead ones), no biggie.

As far as the rifling and lead go...I would get some advise from the company.

 

[JD338]

Rem 700

.451 is jacketed bullets and .452 is lead.

JD338

 

[Rem 700]

That makes sense...thanks.