Is .002-inch over bore size too much?

[RG1911]

I finally got around to slugging my inaccurate Schuemann barrel in my IPSC 1911 and was a bit surprised to measure it at .4495-.4500. I've been sizing my cast .200-gr SWC to .452. (That diameter was determined based on a different barrel.)

Before I order a new sizing die for my Star sizer/lubricator, could .002" over bore diameter contribute to accuracy problems (and leading)?

Thank you,
Richard

[osteodoc08]

Unlikely your source of poor accuracy and leading. What loading? What lube?

I'd consider that .002" about perfect.

[RG1911]

I'm working up loads, again, but velocity with the current load is 870 fps and the lube is Rooster Red. I'm working for a velocity of 850 fps for Major power factor.

Richard

[Outpost75]

Groove diameter of the barrel is not what matters. Measure a chamber cast or throat slug to determine the diameter of the unrifled portion ahead of the chamber before the rifling starts.

In tight-chambered M1911 pistols bullet diameter is limited by chamber size and brass thickness.

Rounds should fall into and out of the chamber of their own weight, using the dismounted barrel as a drop gage. Also check to ensure that case heads do not protrude above the rear face of the barrel hood.

The Lee Factory Crimp die is your friend.

[9.3X62AL]

Groove diameter of the barrel is not what matters. Measure a chamber cast or throat slug to determine the diameter of the unrifled portion ahead of the chamber before the rifling starts.

THIS is my "rule of thumb"/starting point for determining bullet diameter in my autopistols and rifles. This dimension or .001"+ is almost always appropriate after test-drives. I haven't had a leaded barrel in quite a long time.

[nhrifle]

Providing your loaded rounds chamber without a problem I wouldn't suspect boolit size to be a problem. Take a good look at the crown on your barrel. If there are any nicks or imperfections, they can affect accuracy and it is an easy lathe job to correct. Also Make sure the barrel and slide lock together solidly and that the muzzle end of the barrel fits snugly in the barrel bushing.

[doc1876]

there was a post her a few weeks ago about reaming the chamber of a 1911, and he stated that he really picked up accuracy afterwards.....just a thought

[harley45]

One thing to watch for with a boolit .002 over is the nose engraving on the rifling, on a lark one time I tried going .002 over in my Wilson Combat 10MM they would feed and fire fine and didn't lead the problem with some of mt longer nose boolits like from my Lee mold was they would engage the rifling and sometimes hang up just enough to require a tap on the rear of the slide to go into battery. It was also a huge bear to rack the slide back to remove the rounds.