Measuring slug from slugged rifle barrel

[JRiddle]

I just finished slugging the barrel on my .303Brit.  It has an odd number of lands/grooves, so just opposite my land I have a groove.  How can I accurately measure this slug.  Apologies if this has been addressed before but I didn't see it.  Also on the same subject, I also just slugged my 7.62x54R. I got .3135, what bullet would be best suited for that?  Thanks JR

[Glanceblamm]

It is a "V" shaped contraption that gives one a measure then allows you to make a conversion. I cannot remember the name of it though.

[quickdtoo]

There are other ways that aren't quite as accurate, here's one.

Tim

http://books.google.com/books?id=7Ab12fHr8y0C&pg=PA207&lpg=PA207&dq=measuring+odd+number+grooves+bore+slug&source=bl&ots=uduG6MqZ-l&sig=tCSH91NdjpkPVDC1YRKD1Wk8gAQ&hl=en&ei=hOpQSuTULoXUtgPy7-iqDQ&sa=X&oi=book_result&ct=result&resnum=1

[JRiddle]

Thanks for the info guys, Tim I loved that link, I had no idea you could google books.  I got lucky today, talked to a guy after church today about this situation.  He said he had a friend who did tooling for a bearing company and he'd run it by him.  He called me while ago and said if I'd get the slug to him, he would take it and use a tri-mike (not sure of the spelling) on it.  He says its basically a micrometer that gauges from 3 points instead of two.  He said that it would only be accurate to the ten-thousandths, if I needed more accuracy he'd have to use the computer/laser scanner...    I said I'd just settle for the ten-thousandths.  I took the slug to him this afternoon, he said he'd call me tomorrow afternoon, can't beat that for service.  I think I'll try that method in the book link that Tim sent when I get my slug back, just in case his tri-mike is off 
Thanks again, JR