Slugging a barrel for propper reloads

[WLE]

Is slugging a barrel for my 45 for reloading really that important to know for reloading. Can .001 thousandth of an inch really effect the accuracy of the bullet for short range shooting? I use a mic on my leaded bullets and they are sometimes .001 less then what they claim. Is sizing more important when you are using jacketed bullets. Lead being softer can compress easier. If the bullet is larger then the riflling, can excess pressure build up and is this a problem. I'm loading .452 dia LRN which in reallity measure .4527 to .453. Thanks all for you help, Bill

 

[rcmodel]

Size is importent with lead bullets because if they are undersize, gas can escape past the bullet and cause gas cutting / bore leading.

Over-size is not a problem with pressure or safety as long as they are not too big to fit in the chamber.

With lead bullets, bigger is better in fact.

Slugging a .45 ACP for jacketed bullets is usless, because jacketed bullets only come in one size. Even if you found you needed .002" bigger .45 ACP jacketed bullets, you can't get them anyway.

Thinking back on it, I have probably never slugged a .45 ACP 1911 barrel in my life.
I have slugged .45 ACP revolver chamber throats, and used over-size bullets in them, but that's a different deal all together.

rc

 

[NCsmitty]

Optimum lead bullet size should be .001-.002 larger than the bore size, for example, a .452 bore works best with .453-.454.
Jacketed bullets should work best with actual bore size.


NCsmitty

 

[Jim Watson]

Sorry, smitty, that is not the bore diameter, it is the groove diameter.

The difference between bore and groove diameter is about as complicated as the difference between clip and magazine that is so often explained on the internet and a good deal more important when it comes to actually shooting the gun.