Reaming barrel for lead bullets

[Zoomy]

I am having a custom 2011 limited being built in .40 S&W and was going over the specs on the build sheet.

I noticed that the barrel would be reamed for lead bullits. I feel so very ignorant, but why does a barrel need to be reamed to different dimensions in order to use lead bullets? What size or dimensional changes are made and how will it effect the use of jacketed bullets?

[DWFAN]

What did your gunsmith say when you asked him this?

[Zoomy]

What did your gunsmith say when you asked him this?

I did not ask him yet. I just noticed it in the spec sheet and tossed the question here first.

[GuildSF4]

Most of the time that I have heard of this procedure being performed it is to increase the leade so that the lead bullet is not touching the rifling when chambered (sometimes called throating and performed with a throating reamer, not to be confused with polishing the feedramp and breaking the corner at the entrance of the chamber (which is called throating and polishing the feedramp)).

I would however ask your gunsmith what he means by this.

[rishii]

I would guess he's throating the barrel to allow the use of long loaded 40 rounds

Most of us load the 40 round longer than book max length, to get them to feed in our double stack guns, I load mine to 1.850

However with lead bullets, the bullet will hit the rifling and not allow the round to fully chamber, to fix that you have to cut the rifling back some with a throating reamer

It's a common practice and it shouldn't affect your jacketed bullet performance

[HI5-O]

I would guess he's throating the barrel to allow the use of long loaded 40 rounds

Most of us load the 40 round longer than book max length, to get them to feed in our double stack guns, I load mine to 1.850

However with lead bullets, the bullet will hit the rifling and not allow the round to fully chamber, to fix that you have to cut the rifling back some with a throating reamer

It's a common practice and it shouldn't affect your jacketed bullet performance

I think he means 1.185

[Zoomy]

Thanks, it all makes sense now. I called a friend who shoots a 2011 and he said that the lead bullets need more clearance than jacketed.

[benny hill]

It is not the length but the dia. of the bullets. Reamer are usually .400 at the lead but they make a .401-2 for lead bullets.