I've always wondered this. I guess it is called overbore in some circles. But, is there a point with a .223 Remington shot out of a barrel with a 1x12 twist, that you can load a 50 grain bullet to such a fast velocity that it will not stabilize right (wide-open groups)? And if this is possible, is there a formula for figuring out at what velocity should a handloader stop with each bullet weight in a given barrel twist for a given caliber? Or, is it simply called experimentation? Thanks ... Tom Purdom

A 50 gr bullet from a 1:12 twist should be good at any speed. If you are getting really bad groups at high speeds and better groups at slower speeds, it is something else causing it.

I don't know of any such formula, however, in my 50 yrs of reloading, I have found that there is a certain velocity that a given barrel will perform best at with a given bullet weight. You find it by trial and error.

You will get acceptable groups for hunting purposes no matter how fast you drive a 50 grain bullet out of a 1-12 twist barrel.

I have found, with a few exceptions, that I get the best accuracy from a load that is usually less than max by a couple hundred feet per second.

The Barnes X bullets are an exception, they like to be driven as fast as possible. I suspect the GS bullets, given how they are made would be another, but since I haven't shot any of them I can't say for certain.

Hope this helps.

Pecos