Chamber Sizes

[EdMc]

Finally got around to measuring the barrels I have using a set of pin gages.

Glock G20SF         0.435    -     0.425

Bar Sto for Colt Delta     0.431    -    0.424

S&W 1006             0.431    -    0.426

Lone Wolf 6.62 Threaded      0.429    -    0.424

Colt Delta             0.429    -    0.425

Not smart enough to know what this proves but there it is.

[sqlbullet]

Interesting data.  Correlates pretty well to what I see case heads doing when I measure them.

[The_Shadow]

EdMc, are the larger numbers what is at the rear of the chambers and the smaller numbers at the front near the end of the chamber?  Tapered cut for easier insertion & extraction.

However the section of brass at the rear of the chamber opening where the case head is unsupported is the most important issue. 

[Intercooler]

No Witness barrel 

[EdMc]

Witness barrel? Simple enough answer...I don't own a Witness to measure.

Shadow, of course the measurements are front to back (barrel). Most have seen the photos....the unsupported area is just above the feed ramp except for the Delta that leaves ~180 degrees unsupported. This Lone Wolf is as tight in the chamber as the Delta and leaves only the small area at the ramp unsupported. Little room for case expansion except at that one small area. I'm not sure that's a positive in itself.

The Smith and Bar-Sto barrels measure and taper about the same with the Glock, of course, being the largest by far. Just for comparison it would be interesting to know the sizing of a Kimber chamber.

[sqlbullet]

I don't have a set of pin gauges, but based on fired case heads, I would guess the Witness would fall about .431 at the rear.  They brass is generally about .002" smaller than the same load fired in my Glock.

[GoldBead]

I agree with the .431-.429 for the Witness barrel. Very tight, which is probably why the weapon is so accurate.  Also, the case is nearly fully enclosed, even at the bottom of the feedramp (see Pic). To blow out this case, you probably would have the primer let go first, because the only exposed area is the solid case head itself. I have shot very high pressure ammo in my Witness (Double tap and Underwood) and have NEVER gotten the equivalent of a "Glock Smile". Also, Tanfoglio's machining is very precise. Not only do all three barrels for my Witness fit, fire and function without adjustment, but even after nearly a thousand rounds the breechface and locking lugs on both the slide and main barrel look new.

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