Bearcat cylinder size old and new

Early Bearcat has a very tight fitting cylinder (front to back has almost no endplay).
Not sure if previous owner installed a later cylinder.
Can someone please give:
1) Dimensions for EARLY overall cylinder length and width?
2) Dimensions for LATE overall cylinder length and width?

You will not find exact measurements,, as there is always minor differences in OAL. It has to do with timing the bbl & fitting the cylinder to the gun.

Once installed, the cylinder cycles normally without ammo. However, it is really tough installing it into the frame opening.
I guess another question would be, "How tight is too tight?"

Most of us install a cylinder,, and check the barrel to cylinder gap with feeler gauges. In general, a gap of .003 is considered pretty good,, a .002 is tight but acceptable,, all while .004 to .008 is acceptable for use. Getting a gap of .010 or larger is usually a bit disconcerning,, as it promotes lead and powder spitting. But I've seen a few guns with gaps larger than .010 that were excellent shooters.
In general, most factory guns usually fall in the .004 to .008 range.

Is there some way of identifying a smaller old model cylinder versus a larger later model?
I understand the later is longer and/or wider, but not sure by how much.

Ok, I'm not sure where you got that info,, but I just measured 4 Ruger Bearcats. On early OM "Alphabet" an OM Super Bearcat, a NM stainless, and a NM 50th anniv. one.
All 4 were almost identical in the cylinder diameters,, and within the normal OAl's found in varying guns where the OAL is determined by the barrel set-back & such.
Both OM's & NM's are pretty much the same when it comes to cylinder dimensions.

Good to have this clarified. Comments elsewhere led me to believe there was a difference, so thank you for the clarification.

Since it's a correct cyl, let's address your complaint.

A couple of strokes with a honing stone held flat on the front cyl hub (gas ring) will take off .001" in no time and end your frustration with assembling the cyl.

must also keep in mind that often when putting the cylinder back in the frame of the Bearcats, there is NOT a lot of room for the lockwork and the pawl may stick out ever so slightly and keep the cylinder from "dropping" in, a simple turn of the cylinder with your fingertips clockwise( from the rear) as its seating ( setting) in the pawl will slip by the ratchet and the cylinder will drop in.....ask me how I know,,,after a few THOUSANDS of installing the Bearcat cylinders, it can sometimes defy the laws of nature............ 8) :roll: :wink: (kinda like the early RSTs/Mk I's...) :shock:

and yes the cylinders are too close to the same measurements......you just KNOW a stainless one is NOT an "old model", nor is the "Magnum marked" one :roll:

Ignoring all except the actual size of the area the cartridges fit into I measured a very early Old model Bearcat and a Super Bearcat. both were 1.35". All the New Model cylinders were 1.40 - 1.41" . The Old Model cylinders will easily fit into a New Model; the reverse is not true.