[Mike Buchanan]

I have several old SxS shotguns from the 30's and 40's and was pretty sure several were 2 1/2" chambers but didn't know how to verify easily.
Then a light went off! I broke down the shotgun and dropped a new used 2 3/4" empty hull into one of the chambers. On several they would stop about a 1/4" short of being fully chambered. I would pick them out and drop another Hull that I had cut to 2 1/2" and it would bottom out and drop out easily if the barrel was turned upside down. You don't really need the 2 1/2" Hull you just need a new unfired 2 3/4" hull.
I am sure someone figuired it out a long time ago but sometimes I'm a little slow.
Mike B.

 

[Ralph McLaney]

Measure...

...the length of the new unfired hulls - they do vary in length.

 

[Mike Buchanan]

The problem is when you shoot 2 3/4" shells in a gun with a 2 1/2" or 2 9/16" chamber. You get a pressure spike I imagine but in any case a gun with nasty recoil and usually doesn't pattern as well. I have several old Fox Sterlingworths and L.C. Smiths that I was sure the chambers were short but couldn't fiquire out a way to measure the chambers.( I'm a retired plumber used to working in feet and half feet!). Anyway I had new Fiochi hulls that measured 2 3/4" and were nice and even at the ends and when you dropped them into the chamber of a short chambered gun they didn't drop in the whole way like one cut down to 2 1/2". You have to take the gun down so so have the barrel separate from the action and the extractors are closed.

 

[zoar]

Mike--- sounds like you figured out a good method. So how many old 2 and 3/4 shotguns did you discover you owned?

 

[Mike Buchanan]

It's the 2 1/2" ones that can be a problem when you try to shoot standard 2 3/4" shells in them. So far I confirmed my suspicions on a 20ga and 16ga Fox Sterlingworth and a 16ga L.C. Smith.
I have been playing around learning to load the short shells and roll crimp them. What a difference the proper length shell makes in the recoil. They are much more pleasant to shoot. I haven't had the time to pattern them yet but have shot a bunch of preserve chukars and pheasants with them.

 

[mdd]

I think the shorter shells were 2 9/16 and only made in 20 and 16 ga. I know alot of old brownings and winchester model 12s shot the shorter shell. There was a common fix, they just lengthened the chamber the extra length.

 

[Rangr44]

Short of having a set of chamber depth gauges (10/12/16/21/28/etc), the next best way to measure chamber depth would be to use a wood dowel a little under chamber size, and wrap the end with tape until it will just slide into the chamber w/o force.

When the tape's wound to the right diameter, slide the taped end into the chamber (gently), until it's stopped by the forward end of the chamber, or forcing cone.

Mark the dowel at the rear of the chamber, withdraw it, and measure from the mark to the front edge of the tape for the chamber depth.

.

 

[Cheezywan]

Purdy savy observation Mike B. Simple way for us to "make do" with what we have.

I haven't had the need to work out chamber dimentions for awhile. Last time I did, I concidered turning out some head space gauges on a wood lathe from some hardwood.
I didn't have one so I did something else to figure it out???
Anyway, if you have or have access to a wood lathe it should be purdy easy to make some gauges to add to your tool kit!

Cheezywan

 

[Virginian]

I cut an old credit card and use that for a chamber gauge. Works quite well, and you can mark and label it with a Sharpie and it lasts.

 

[zoar]

Darn good use for a credit card!!!!

I cut all mine up when the bank tried to charge me 29.9 per cent interest for being a day late . Never used another credit card but now have a sound use for them.