Bullet Diameter - 45 ACP

Lead bullets for 45 ACP are typically 0.452 inches in diameter. Most published data uses lead bullets of this diameter.

If you have - or are going to use - a bullet with a larger diameter you will need to reduce powder charge as the barrel has to draw the bullet to a smaller diameter and that resistance will increase pressure.
 
What does your reloading manual say?
Hodgdon states 0.451 for cast and jacketed.
What you plan to shoot them in may also matter. Glocks have polygonal rifling, as opposed to conventional lands and groves.
 
My Hornady Handbook list .452 for their lead semi-wadcutter, .451 for jacketed. My Sierra lists .4515 for jacketed...if that's any help.
 
hdwhit said:
Lead bullets for 45 ACP are typically 0.452 inches in diameter. Most published data uses lead bullets of this diameter.

If you have - or are going to use - a bullet with a larger diameter you will need to reduce powder charge as the barrel has to draw the bullet to a smaller diameter and that resistance will increase pressure.
Click to expand...

How much will pressure go up?
 
As previously stated, jacketed bullets usually are 0.451" while lead is usually 0.452".

Sierra does list theirs at 0.4515".

You can find 0.451" lead. And they should shoot accecptably from your pistol.

Again assuming it's not a Glock.
 
for my Hi Point 45 ACP carbine I size my Lee 200 gr. powder coated SWC to .452" I also size my NOE HP, Cup Point and RNFP bullet to 452" as well.
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Lead bullets for 45 ACP are typically 0.452 inches in diameter. Most published data uses lead bullets of this diameter.

If you have - or are going to use - a bullet with a larger diameter you will need to reduce powder charge as the barrel has to draw the bullet to a smaller diameter and that resistance will increase pressure.
Click to expand...

With jacketed bullets, yes, but not with lead. Lead is soft compared to copper, and will easily swage down without raising pressure any measureable degree. I regularly shoot .455" bullets in my .45 Colt with a .452" barrel.

Don
 
Even with jacketed bullets there is some leeway. The military allows .30 cal groove diameters as small as 3.065" and jacketed bullets as large as 3.09. I have an old French MAB for .32 ACP that has a .309 bore, while commercial bullets range from .310 to .312 for it. You already squeeze a typical high power rifle bullet down 0.004" with the lands, plus sharply bend the jacket at the corners of the lands, lengthening the bullet a little, so some of this is normal for the gun to experience.

Occasionally you hear of someone firing a jacketed .30 cal bullet through a 7 mm bore or an 8 mm through a .30 cal bore and getting away with it (though this was blamed for the blow-up of some low numbered Springfield '03's in battle; German 8 mm round in .30-06 chamber). There are some pressure signs by then, though.

As for lead, as already stated, it's generally too soft to cause a problem. Revolver accuracy typically requires you to use a lead bullet cast close to the throat diameter. There are a lot of .45 Colt revolvers that had .455-.456 throats for the old .454 bullets, but with .451 bores, so that loading bullets from the old .454 molds would still be possible. They still shot OK.

With lead bullets you want to try different diameters until you find what is most accurate in your gun. My Goldcup like 0.4525 cast bullets very well. Smaller or larger tends to open groups a little.
 
Bucksnort1 - As Unclenick posted, the 45Colt was the first thing I thought of when I read .455. Though I have no experience with the round, I can remember a time when the 45Colt and 45ACP barrels differed by a few thousandths.

Can you run them through a sizer?
 
Bullets in the .455 range are probably meant for .45 Colt. The most important question is the weight appropriate and will they feed correctly.

To answer your other questions - Yes, a starting charge will be OK.
Yes, they make "bullet sizers" Google "Lee .452 sizing die". Bullet casters use these to size bullets.

Honestly, the bullets will probably swag down in size when seated into the case. If you use a Lee factory crimp die it should size down any bulges in the case.
 
.452 is what most of us ask for but I have .451, .452 and .453 depending on who you get the bullets from. All seem to work in my guns.
 
Note: The reference I made to a .455" bullet, as I stated, was used in a .45 Colt, not a .45 ACP, and was made simply to show that moderately oversized lead bullets are of no concern pressure-wise. The only time you would do this with a .45 ACP is if you have a Smith & Wesson Model 25-2 with large throats. I size lead bullets used in my Model 1911's to .452".

Don
 
A bullet with a larger diameter is the wrong bullet. What happens to a .451" barrel with a .454" bullet depends on the bullet and the quality of the barrel. A 1911A1 barrel might bulge with a jacketed .45 Colt bullet. Probably wouldn't with a cast bullet.
An 8mm through a .30 cal bore blows the receiver. That's how both 1903 and M1 Rifle got blown up.
.455 is Webley diameter.
 
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