Hello, I ordered some lead bullets from Matt's Bullets for my GP100. I've measured my cylinder throats to somewhere between .358 and .359 with pin gauges. However, I messed up my order and received one box of .358 and one box of .359. I suspect that if the .359s will chamber, all will be fine since they are lead. Has anyone shot lead bullets that are a few one thoudsandths over the throat diameter? I won't be running rip-snortin' Elmer Keith loads, just moderate ones. Thanks.
The cast lead simply swage down passing the throat to the forcing cone.
Have you verified the measurements of the purchased bullets. I have always sized my bullets for my 38/357 cartridges with a .3585" size die. Not by choice, but by chance. You will reduce your powder charge since you are changing a component anyway, so as long as it falls in and drops out of the cylinders, you should be just fine.
You should have no problems with either of the bullet diameters as far as the throats of your cylinders. As long as the groove diameter is not oversized they should shoot well. Typically lead boolits are sized .001" over barrel groove diameter and your throats are also .001" over groove diameter. This is a general rule of thumb for us lead boolit shooters.
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If the bullet has any .359 bearing surface outside of the case you may have a problem trying to chamber that in a .358 throat.
Thanks for the responses. My cylinder throats allow a +.358 gauge to enter, so they are at least .3583 in diameter. A -.359 gauge won't pass through, so they are .3588 maximum in diameter. They all seem to be the same size which is good. I mic'd my bullets and they measure .3588-.3589. I suspect that a few ten thousandths won't matter. But I will think about it and might buy a .358 sizer for my Saeco lubrisizer.
I think you'd be fine with it.. And for s&g's I'd see if a .359 projectile in a dummy case will drop in and fall out of the cylinder. It's likely the restriction of the cyl mouth is at the very end of the cyl before the forcing cone. And no..a few tenthou's won't matter from .3588 to .3589
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