.454 dia lead bullet; .451 dia. gun barrel. Dangerous?

[DG45]

I have a Brazilian contract S&W 45 cal revolver. I keep it loaded for HD with Black Hills Auto Rim 255 grain LSWCs. This load is rated at about 755 fps, but I believe it is actually goes just over 800 fps from my 5 1/2 inch barreled revolver. It's a thumper, but the stuff is expensive so I've fired less than half a box since I bought it because I can't afford to use it for target ammo. I don't know much about reloading, but I've been trying to learn which may be a mistake because so far what I've learned has me worried. Til now I've always assumed that if it a box said 45, it was ok in my 45. Not so sure now.

I'm not sure what the bullet diameter is of the Black Hills stuff I have but I seem to remember reading somewhere that it's .454 dia. If true that's pretty thick for 45 ammo. I read somewhere else that the diameter of a 45 bullet should be no more than .001 bigger than the inside diameter of the barrel. Then I read where someone had measured the diameter of his S&W Model 1917 and found it was .451 dia. The Model 1917 is nearly identical to my gun.

So , my questions are these:
1. Does anyone know what the actual diameter of Black Hills Auto Rim 255 grain LSWC's is?
2. If I have a .451 dia. barrel, and if my Black Hills Auto Rim 255 grain LSWC ammo really is .454 dia., is it dangerous to fire ammo that's .003 oversize in a S&W revolver that was manufactured in 1937?

 

[WESHOOT2]

so, how does it shoot?

1) Close enough.

2) No.

 

[DG45]

Shoots ok. The gun is not what I'd call a tack driver with any ammo, at least it's not nearly as accurate as either my my Colt PPS 38 Special or my Colt OP 38 Special is, but it's ok for what I expect of it. It's perfectly capable of taking out any night intruder who breaks into my bedroom univited who I might have to deal with before I can get to my shotgun. The heavier 255 grain bullet prints higher on 10 yard target than 230 grain 45 ACP ball does, but I expected that. Accuracy seems about the same otherwise but accuracy is not the issue.

 

[AlaskaMike]

I completely agree with Weshoot2. Considering the pressure involved in those loads, .003" with a soft bullet isn't anything to lose sleep about.

The other thing to keep in mind is that you really don't know that those are .003" oversize because you haven't measured them, and you haven't slugged your bore to measure it either.

 

[zippy13]

DG45,
If you slug your barrel, then you won't have to be guessing about your size. I concur with the others, many soft lead .454 bullets have gone down .451 barrels without the shooter being aware of the difference. My replica Bisley .45LC is .451 and it's never had anything other than soft lead .454's.

 

[DG45]

Thanks to all. I feel better already!