Measuring Throat Diameter?

[DeadWood]

O.K. trying to obsorb alot of info. today......To get started i've settled on purchasing some Lyman's 311440 bollits, so i can load some general rounds with 2400 and hunting rounds with H335 (which i currently have) for my .30WCF.

I've watched a video on youtube and somewhere today read a thread on how to measure the bore and can't find that thread now!!! Could someone please direct me to such a thread or/and give me a list of materials i need to accomplish this?

[mroliver77]

I use a fired case. I shorten the neck about 1/8" I then fill to almost full with lead or use a rod or something to fill the case to just below the top. Lightly oil bore and throat/neck section of barrel. I then use pure lead dropped down from the muzzle. 180-200gr for a .30. I use a steel rod as close to bore diam as I can find and wrap electrical tape around it every few inches to center it and protect bore. Use a heavy hammer and give a couple nice firm raps on rod end. when lead is upset into throat the hammer will bounce and not feel "dead. Dont overdo it! Better to retry then to stick a slug in the throat. Open action and mebbe help push with the rod to remove case and chamber impression. Amazing how perfect an impression you can get!
One note is I use .30 cal boolits from "pure" lead rolled between two pieces of steel plate to reduce to bore size.
Jay

[Wayne Smith]

Mroliver gave you one option. The other is to go to Brownells.com and get some cerrosafe. It melts around the same temp as boiling water. Block your bore with a tight patch, melt cerrosafe and heat your action with a hair dryer. Pour your cerrosafe and, as soon as it hardens, tap it out with a rod. Within an hour it will be at the size of your chamber.

[pdawg_shooter]

Plus 1 on the chamber cast. I do the chamber, throat, and about 2 inches of the bore. I have all the dimensions I will ever need and record them in my firearms record book. I remelt the cerrosafe and reuse it again.

[largom]

The advice given by mroliver77 is the easiest and fastest for the inexperienced. The Cerrosafe I have melts at 158 Deg. and makes a great cast of your chamber giving a lot of information. However, it is best to disassemble the gun as much as possible before applying. If you pour in too much cerrosafe and it gets into locking lugs you can only get it out by melting it. Also, I have found guns with rough chambers that created problems in removing the chamber cast.

If using the slug method just be sure to lightly oil the bore AND the slug as suggested. Do not use a wooden dowel rod to upset the slug, use a metal rod. Wooden dowels can break and then jam into the bore which creates a major problem.

Larry

[mroliver77]

Also the cerro safe is only the right dimensions for a short time.
The upset impression is stable and may be referred back to indefinitely.
Jay