Headspace and revolvers

[BillBro]

Awhile back someone posted some specs pertaining to headspace and B/C gaps for different calibers of revolvers. I believe it listed .068"- .061" for a 45 caliber rrvolver and B/C gaps anywherr from. 005"-.013 or .015" or something like that. Being the curious soul I am I went and got two of my 44 caliber revolvers to measure, a 696 and a 29. The 29 has a B/C gap of .005, .003" of endshake but the headspace measurement is .059", if Im checking it correctly. Im assuming it's measured behind the firing chamber, between it and the firingpin hole?? Correct? Incorrect?
The 696 has a B/C gap of .007", .003" of endshake and headspace measured .062".

My questions are what is the significance of the headdpace value and how does it effect the firearms performance, either operationally or from a performance standpoint. What does a value below this stated minimum mean? How does it get to where it is?

Yes, the gun operates fine do should I just not bother myself with it? Im not frettung about any of this because as I said the gun operates fine but learning something new always appeals. Thanks.

 

[armorer951]

Headspace or "rear gauge" and B/C gap, or "front gauge" as it is sometimes called, are listed in the armorer's chart below. Note the date at the top of the page. This is from an old armorer, out of an old manual.
I believe a front gauge of .012" is now considered acceptable by the factory.

Ideally, these gauges are set when the revolver is assembled for the first time at the factory, and can vary quite a bit, depending on the parts selected, and the skill of the fitter. Generally, the b/c gap decreases over time because both wear and tear and battering of yoke during recoil cause the cylinder to move forward. This movement forward due to wear, also causes the rear gauge or "headspace" to open up.

Headspace that is overspec can lead to reliability issues and misfires due to the excessive space between the breechface and the base of the shell casing. Too little space here can also cause issues like binding of the cylinder and other problems.
Also, while "end-shake" is often frowned upon, it is both a factory built in gauge, and an absolutely necessary one in the cylinder assembly, if the revolver is to work as designed.
If the front and rear gauges are "in spec", then the amount of end shake on the cylinder is a moot point.

I would consider your measurements normal, and would not fret about the "tight" rear gauge as long as you are not having cylinder rotation issues. I would much rather have a headspace close to minimum. Please remember too that these measurements are best taken after a thorough cleaning and wipe down. Any debris will cause erroneous readings.

 

[BillBro]

Thanks Mr. Armorer. No worries nor problems on my end with any of my guns currently.

All guns were, as they always are, cleaned well. I always clean thoroughly after each trip to the range. Its just habit. I actually start cleaning before I leave the range.

The above chart is the one I saw and figured it was older just due to its appearance, it looks aged. From my reading jere and elsewhere Ibe seen that S&W's standards have changed quite a bit over the years.

My main curiosity was about the "headspace" spec and what it could affect and how. The one consequence of an out of spec value you mentioned is not an issue with my revolvers.

Again, learning something new is what it should be about.