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Discussion Starter · #1 ·
for the purpose of math. if your bore diameter is .355 would you want a .355 bullet or one a few thousands bigger? What would happen if your bore was .357 and your bullet was .355? would your groups open up? educate me
 

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I am assuming that you are talking about lead bullets? If so, bullets .001 - .002 larger than bore is recommended because they will give you a better fit to the bore. Advantage, driving bands actually drive the bullet down the barrel in a more staple attitude; thus improving accuracy -- the tighter fit helps to prevent "gas blow-by" around the bullet; thus reducing the possibility of leading.
 

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Jacketed is generally bore size I believe, i.e. .355 bullets in a .355 barrel, while lead is .001 or .002 over as Captain mentioned.

Wil Schuemann of Schuemann Barrels told me he likes to run .001 or even .002 over size jacketed and .002 or .003 oversize lead for best accuracy. In some calibers like .40 or .45, this isn't really an option as most vendors only sell one size. This is an option, however, if your bore is .355 (9mm) or .356 (.38 Super). The bullets are not exactly interchangeable, so drop your powder a bit if going up in size and work back up.

If your bore is .357, you will probably be limited to bore size jacketed (Montana Gold, Hornady, and Nosler all sell .357 jacketed bullets) or .001 oversize lead. I could be wrong on the lead as there may be a manufacturer that sells them or I am sure a custom mold could be made. A .355 bullet might shoot really well, but I would be willing to bet the larger size will do better for the reasons Captain mentioned in his post. If you try them and have good results, definitely let us know.
 

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Discussion Starter · #5 ·
well i saw a guy the other day that was loading 9mm bullets into his 38spl. some of the bullets actually dropped into the case. I have read were people shooting the HOT 9mm major aka 9x23 and getting better results with over sized lead than with jacketed bullets the diameter of the bore...
 

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I didn't think about the smaller bullets falling into the case. That would cause me a little concern.

I only know one shooter that uses lead in an Open gun at major, and he looks like a train "puffing" through a stage. Works for him though. My guns have all shot the bore size jacketed bullets so I have admittedly never tried anything larger in jacketed. The only lead I have shot has been .001 or .002 over bore size. The size and the fact the lead just seals up the bore better is why you can generally get the same velocity with a little less powder than jacketed.
 

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That smoking like a choo choo train can be very annoying on a hot summer day when the wind aint blowing and you can't see the the targets....caused by using the wrong type of powder with the moly...

The boys at Precision bullets in TX have a portion of their web page devoted to various powders etc to use with moly coated lead

everything stated above is how I know it to be....oversize lead a bit so them driving bands will catch, same size for jacketed and moly coated

Only way to know what you got is slug your barrel...

Some cast bullet makers (like Penn Bullets) will custom size your bullets.

As a matter of fact I have a "custom" Lee sizer coming for my 44 Mag...sized .431 instead of .429...maybe it will get here one day
 
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