Cylinder throats??'s

[750k2]

When measuring I've read the pin gauge is the preferred method but can one use a
dial caliper to measure?
Has anyone polished theirs with flitz?
What other tweaks do you guys use?
[smilie=1:

[9.3X62AL]

My skill level with dial calipers causes me to slug the throats, then measure the slugs with the calipers or micrometer. I've tried using the calipers' inside jaws, and I don't do a very accurate job of measuring the throat.

[454PB]

I've found that I can measure cylinder throats to within .0005" accuracy using vernier calipers. I determined this by using both the slugging method and the calipers.

[44man]

Most calipers have flat faces and will not give a good reading on ID's. File to a razor edge and they can.

[NVcurmudgeon]

Slugging the throats of a revolver is so easy compared to driving a slug through a rifle barrel. It is especially beneficial with hard to measure five-groove S&W barrels. I slug the throats and trust that the good folk at Springfield didn't make the barrel bigger. I hear tell of some makes of revolvers that you can't do that with.

[S.R.Custom]

The folks at Springfield are no better. Trust me. :roll:

[shooting on a shoestring]

I always measure mine with a split ball and micrometer. A split ball being a gadget that is much like a ball split in half with a wedge that moves up between the halves to push them outward. Its built together on a handle with a threaded tensioner to move the wedge. The split ball goes into the chamber throat and is expanded by the wedge until it contacts the throat walls, then removed and measured with a 0-1 mic. Fast and easy once you get the hang of it. I can discern tenths of a thousandth this way ( I grew up in a machine shop and that has paid dividends in several arenas). I bought my split balls back in the 70s but I'll bet they are still less than $30 a set, and a Starrett 0-1 is probably in range of $60 or so new and every one that reloads should have at least one 0-1 mic.

[BD]

I think you can get a good approximation of the the chamber mouth dimension by slugging the chambers, or using a sharp caliper. However to measure the chamber depth and throat you'll need pin guages. You can think of a revolver chamber as being two concentric holes, a large hole for the case diameter and a smaller one for the chamber mouth. The throat is the transition between the two diameters and it's generally reamed by hand. Reamer designs vary, and the skill of the guy doing the reaming varies. Reamers taken to extremes will open the chamber mouths to some degree. Some manufacturers apparently bore the smaller diameter a bit undersize and count on the reamer to bring it up to bore diameter, (or not). The pin guages tell you the depth of the chamber bore and give an indication of the depth of the throat.

Uniformity in these dimensions can result in an accurate revolver. Under reamed cylinders can be brought up to proper specs, but gong the other way is very hard. I started looking at this as a result of my search for an accurate Redhawk in .44 mag. After buying and trading four or five I got to thinking about how to determine if one had good prospects before having to pay for it.
BD