Slugging or Chamber casting

[dromia]

What method do you prefer to get chamber, throat, bore and muzzle dimensions, slugging or taking casts and why?

I lean more to taking casts, I like to have that visual picture of chamber, throat and bore. I also get more consistent results this way that is probably as much me as the method.

Slugging is good for finding minimum bore diameter if you have tight spots so with new to me barrels I usually drive a slug through it to check.

[leftiye]

Both. The casts will give you a good picture of how your chamber is laid out (plus an inch of barrel). The cast isn't really accurate as per size- the metal expands some- except IIRC about a half hour after casting. But it is close enough for everything but groove measurement. Knowing what your chamber neck diameter is, what your freebore looks like (tapered?), and what your leade looks like is quite valuable.

Slugging can be done for the muzzle and breech only as well as full length, so as to know if the front or rear might be tighter, and what the minimun size overall is plus if there are tight spots.

[Ricochet]

Like leftiye just said, driving a slug in the neck/throat part of the chamber and rear of the bore, well oiled, and pushing it back out, tells you everything a casting would. No change in dimensions later, either.

[joeb33050]

With a lead filled and sticking out cartridge case you can slug a chamber, throat and bore and have a easy-to-see model of the whole thing.
See the book at http://sports.groups.yahoo.com/group/CB-BOOK/, 2.1 MEASURING GUN DIMENSIONS, How to slug a rifle throat.
Here's a picture of the result, maybe.
joe brennan