My 1927 16 gauge VH has 2 1/2" chambers on a 1 frame. I also shoot other 2 3/4" 16 gauge guns, and I am thinking about lengthening the chambers to 2 3/4# on the Parker, so that I don't have to worry about which cartridge I put in the gun.
Are #1 frame 16 gauge barrels stout enough to lengthen to 2 3/4"?

The Winchester super X one once measure 2 5/8 so do Agular and hearters

I don’t mean to be argumentative, but the Winchester super X game load is what I shoot out of my modern 16 gauge gun. The spent cartridge measures two and three-quarter inches overall and 2 11/16 inches to the base of the rim.
Saami standards measure length from the standing breech.
Those cartridges will extend 1/4 inch beyond the chamber and into the forcing cone when fired.
My question is, “is that safe?”
I certainly don’t know, but I did have the forcing cones lengthened in hopes that it would make using modern ammunition more safe.

After much back and forth and hesitation I sent my 1 frame 16 ga barrels to Michael Orlen in Amherst MA. 413 256 1630
He evaluated and said there was plenty of wall thickness to go ahead and lengthen the chambers. I’m very happy with the outcome. I can use 2 3/4 shells - light loads - that are available locally.
Before lengthening the chambers the gun was sometimes difficult to open as the shells seemed to have been forced backwards and expanded in the chambers after firing.

Well the Winchester 1 once i had measure 2 5/8 the once and 1/8 measured 2 3/4. The way they swap makers there is no telling, but the batch of hulls I was given were short.

My cartridges are 20 years old. Dick's Sporting Goods had a $4.00 price on 16 gauge Winchesters, so I bought all they had (8 flats or so). That's a lifetime supply of game loads, since I don't shoot clays with my 16s!
Lengthening the chambers 1/4" seems the best solution. Thanks.

Steven: to address your question regarding safety of chamber lengthening; it's very likely to be safe.
I had Briley lengthen a 20g Parker with chambers shorter than 2 1/2" without problems. The safety of doing so is entirely related to the end of chamber wall thickness, and most U.S. doubles had generous walls.
That does NOT apply to lightweight British or Continental small bore game guns.

The lengthening must however be done by an expert.
An example of "inexpert" lengthening resulting in a bulge just past the end of the chamber

https://photos.smugmug.com/Barrel-Ev...R%20%234-L.jpg

Mine will be going to Briley too!
Nobody has the precision machining that they do.

I just put one empty on the calipers.
It was 2.722”.
So less than 2 3/4”��
But not by much.

Even 20 gauges?
I just bought an O frame 20 gauge Trojan shooter with 2 1/2” chambers.