Stupid question about Bullet size

[kealil]

Hello all,
I have a question. How big can a bullet be compared to bore size? For instance, suppose a bore is .311. A cast bullet is considered best when it is .312 in this case. But what if the bullet was .313 or .314 or even larger. Obviously there is a limit to how big a bullet can go for a gun. Before long you wouldnt even be able to chamber a round or before the bullet will no longer be accepted by the brass.

But what is considered the safe limit? I ask for two reasons:

1. Curiosity. I've not pondered this problem before and it seems interesting.
2. Attempts at experimentation. I have several rifles with very close bores but none are the same and the varying sizes in the same range is causing problems with my ability to size and organize the various bullets. If I could at least attempt (SAFELY) to try some bullets of similar size, I would be very happy.

Thank you for any advice!

 

[Snyper]

I wouldn't want to go more than .003 over.
Larger would still be "safe" in most cases but will be more likely to cause leading/fouling problems

 

[skizzums]

I can't say what had been determined "safe", but have run .003 over in pistols with no harm, r

 

[McShooty]

It is not to be recommended, or course, but I believe there should be no problems firing oversize lead bullets to the extent .003, .004, or even .005 inch. What will happen is that the oversized bullet will be swaged to bore diameter in a short distance and from that point will not cause any pressure increase.

 

[T. O'Heir]

Several rifles with very close bores but none are the same don't count.
Given the numbers you're using, I'm guessing it's a Lee-Enfield. Lee-Enfield barrels can measure from .311" to .315" and still be considered ok. (Over .315" is shot out.) No commercial bullet manufacturer makes a jacketed bullet bigger than .312". You can, however, find molds that go to about 314". Lyman, I think.
Anyway, the Brit has a nominal bore diameter of .303" and a nominal bullet diameter of .311", so there's a fair bit of leeway. Three thou is really nothing.