The Obligatory 4" Revolver Picture Thread

[Wheeler]

I'm embarrassed to say that I don't know. The bore looks great, though. I don't know how to evaluate the rest of the stuff

Lock up and end shake are easy.

Unload, then triple check to make sure it didn't magically reload itself.
Close the cylinder, cock the revolver with the hammer.
Holding the butt with one hand and the cylinder with the other, first attempt to rotate the cylinder. There should be a little play but not excessive.
Then attempt to move the cylinder back and forth between the recoil shield and the forcing cone. If there's more than a couple thousandths of movement you have an endshake issue.
Repeat with the other five cylinders.

Timing is a bit more involved in that you need a properly sized dowel that will fit snugly in the muzzle and slide the length of the bore and into the cylinder.
Once again with the pistol cocked in single action, slide the dowel down the bore, through the forcing cone and into the cylinder. If the dowel is stopped by one edge of the cylinder, you have a timing issue.

An alternative is to shine a light through the cylinder to forcing cone gap and use the Mark 1, Mod 2 eyeball to see if you can see part of the cylinder while looking down the bore. It's field expedient but not nearly as accurate as the dowel method.
Once again repeat with the other five cylinders.

[jh9]

I'm embarrassed to say that I don't know. The bore looks great, though. I don't know how to evaluate the rest of the stuff

I don't know of a definitive guide for checking. The Kuhnhausen manual is often cited, but is not a how to guide by any stretch of the imagination.

timing: put empty brass in all six chambers. Pull trigger, put a little drag on the cylinder with your offhand thumb. The cylinder stop should lock into the cylinder before the hammer falls. 3/4 is I think considered ideal. If you can make the hammer fall and THEN rotate the cylinder into position the timing needs to be fixed. Pre-CNC revolvers had the extractor fitted to the cylinders individually. I've never done this. It sounds like considerable effort. Post CNC guns the extractor is interchangeable. Only the hand needs to be fitted, AFAIK. Your gun is...pre CNC. By a...couple years. Parts will be difficult to find, I think.

lockup: the cylinder should rotate "a bit". The side to side play should be minimal. I don't know if there's a hard metric for this. "Not a lot". Endshake is .002" max in all six positions between the cylinder face and the barrel. The yoke shouldn't wiggle on the fat part at the bottom when the cylinder is closed. Both have bearings (so a little can be taken care of without major surgery if it does this.

[jh9]

Timing is a bit more involved in that you need a properly sized dowel that will fit snugly in the muzzle and slide the length of the bore and into the cylinder.

I think this is spot on for a thorough check. I admit I'm lazy about this part. Unfortunately, if the cylinder stop locks in property it's possible (maybe likely?) that this isn't a timing issue as much as it's a "the cylinder wasn't machined correctly" issue. Timing is bad. Chambers not drilled in the right place is even worse.

[SLG]

... Timing is bad. Chambers not drilled in the right place is even worse.

True, but it is pretty common to find guns that don't "see straight" from their chambers to the forcing cone. Not usually much of an issue, though it certainly can be if bad enough.

[41magfan]

I wouldn't overthink this too much as service grade accuracy is readily achieved without perfect alignment and a tight fitted cylinder. Unless the cylinder has been line-bored correctly, every charge hole is likely going to be off just a little. But that's no big deal because a properly cut forcing cone will generally mitigate any slight misalignment and the gun will usually produce acceptable results unless a tightly fitted cylinder stop prevents a smidge of "wiggle" in the cylinder.

Much like a semi-auto pistol, a tightly fitted slide is just one piece of the puzzle in achieving mechanical accuracy.

[Wheeler]

I neglected to include "a little play is acceptable..." My personal rule of thumb is if I can eyeball down the bore and see the edges of the chambers on the cylinder face I need to move on.

[S391]

[167]

An old beater.

[LSP972]

I don't know of a definitive guide for checking.

This is what you need to be sure.

http://www.brownells.com/gunsmith-to...s-prod655.aspx

.

[Hizzie]