45 ACP bullet diameter? 0.452" jacketed safe?

windage

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I just got back from Calgary over the weekend. While I was in Calgary, I stopped in at TSE and bought some bulk 45 cal 230 gr jacketed bullets in a 0.452" dia. They also had the same jacketed bullets in a 0.451" dia. format. I asked the guy if 0.452" was for ACP or the Colt and he said 0.452" is for the ACP round. I doubted him but I couldn't at the time remember which is for which cartridge and took him on his word and bought a 500 pack of them.
Now I realize that for the 45 acp round the rule should be .451" for jacketed and 0.452" for lead but there is conflicting arguements on the internet about that. Should I worry about shooting these in my new 45 acp carbine?
 
Depends on the bore of your gun. I've never noticed a difference of .001" to make much of a difference in rifles. I have run .3105 projectiles in a .308 without issue or over pressure. I've also run jacketed .312 projectiles in a Mosin that slugged .311 without any ill effects.

Then again pistols run at much lower pressures to start with so maybe it'll have more effect?
 
0.001" makes a difference if it is under bore size(especially with cast bullets..you get gas leakage and leading). Over it really doesn't matter unless you're running hot loads.
 
Whoops, forgot about the under bore size part. Yeah, that's bad.

As for over bore size most bullet manufacturers use a soft pure lead swaged core inside the jacket which isn't too hard either (compared to how hard copper can get). To get your gun to swage down the bullet 0.001" isn't asking too much really.

For hard cast lead alloy water dropped bullets (significantly harder than pure lead) you usually want the bullet to be overbore by 0.001-0.002" and have the gun swage it down. If that's safe to do then I can't see 0.001" in a jacketed round in a pistol being critical.
 
How did we ever survive without the Internet? It is this marvel of technology that we can thank for the opportunity to obsess about .001 of an inch.

I know but in a pistol cartridge it can mean a huge difference in pressure.
 
Jacketed .45 ACP Bullet and manual brand/info can be .451 and/or .452". Cast should be .452"+
 
How did we ever survive without the Internet? It is this marvel of technology that we can thank for the opportunity to obsess about .001 of an inch.

Why, we read books, of course. And we read them cover-to-cover, and not just the parts we deemed relevant at the time. Sometimes, (gasp!) we read the same book two or more times!

And somewhere along the way the relevance of that .001 became apparent.
 
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