how tight to the grooves can I be?

[akolleth]

How close to the actual groove diameter can you be with a bullet?

I slugged my 1938 Izzy Mosin 91/30 and got a reading of .312

Can I use a .311 jacketed bullet for reloading, or is that too tight? I imagine I can, but don't want to load it too tight and end up with a kaboom.

 

[jr45]

Yes. You can use jacketed bullets at or below the grove size. I believe you can go .001 above grove and be fine...I have not tried it.

 

[Walkalong]

If you are confident in your measurements, .001 under with jacketed will shoot fine.

 

[USSR]

I shoot .309" Lapua D46 bullets all the time in my .308 FN SPR. No problem going .001" over in bullet size; going slightly under in bullet size is also ok, but accuracy may suffer.

Don

 

[dmftoy1]

If it slugged out at .312 then I wouldn't have any problems with a .313 jacketed. (if you could find one) or even a .314 cast. (I'd start with a .313 though. )

Sounds like a perfect candidate for the Hornady 150 Grain Spire points at .312 . .at least that's where I'd start if you don't cast your own.

Just my .02

Regards,
Dave