Any info when they first started?

I got a 1902 Cogswell Blagdon, I measured the chamber with Galazans chamber gauge it says it 2 3/4. I just find it hard to believe they were that early and/or someone had it re chambered to 2 3/4. Looking to order ammo and not feeling to sure. Any help is welcome

What does it say on the barrel flats?

Says load of 1 1/8, British proofs 12C in a Diamond. No mention of chamber length.

I have a book at home that gives the date of those proof marks. I will look it up tonight.

I’ll get some pics and thank you

Ok, on page 169 of The British Boxlock Gun and Rifle by Diggory Hadoke a stamped Diamond with 12 C is a 2 1/2 inch gun.

Diamond with 12 LC is 2 3/4 inch gun.

These proof marks were replaced in 1925 with length of shell chambered in inches stamped on the flats ie 2 2 1/2 or 2 3/4 or 3.

These proof marks were replaced in 1984 with length of shell in Millimeters stamped on the flats.

My 2 3/4 inch reproofed Francotte in Birmingham is stamped per 1925 proof marks.

For a English gun to be reproofed to 2 3/4 inch from 2 1/2 the 2 3/4 inch proof marks would be stamped on the flats per the rules in effect for the time the gun was reproofed. These reproofed stamps must be stamped on the flats assuming rechamber was done in England or Europe by someone reputable.

On page 170 he states Brit guns made before WWII were vastly most common as 2 1/2 inch gun. 2 3/4 inch guns were available pre 1925 see page 169 just not common before WWII.

He also says on page 170 that 2 3/4 inch shells will fit in 2 1/2 inch gun, but do not do it. The cartridge extends into the forcing cone increaseimg pressure and constriction.

He also has pictures on page 160 of a 2 1/2 inch 12 bore showing proof for a 1 1/8 load.

RST makes wonderful 2 1/2 inch cartridges. I shot a bunch the last two weekends the heaviest charge they offer is 1 1/6 oz loads or 1 oz loads at 1200 fps. RST believes in being gentle with old guns.

Forgive prior typos, I am typing on an iPad.

Damn, good work LHeym! I felt sure it was a 2 1/2 chamber but had no way of proving it.
Peter.

Thanks very much for the information. I’ll be ordering some shells! Appreciate the research and proof id.

Glad I could help and think you guys.

My stream of thought typing on an iPad created poor sentences and misplaced page numbers. I have edited that above.

Just ordered some 2.5 paper 1 1/16 loads. Can’t wait to shoot. Thanks again.

Yes those are is a 2 1/2 proof marks prior 1925.there is a picture in the book I was citing from of a gun from 1906 just like it.

I have seen a few original pre 1925 2 3/4 inch guns. The proof marks are a 12 and LC in dimonded and stamped 1 1/4 oz load.

Chamberlin’s in Oklahoma has 1906 with original a 2 3/4 inch chambered Greener for sale.

Standard Brit load for a 2-1/2" chambered gun is 1-1/8 oz. Standard for a 2-3/4" chambered gun is 1-1/4 oz.

If you measure a fired 2-1/2" 12 gauge hull you will see that it is almost as long as a fired 2-3/4" 12gauge hull - less than 1/8" shorter. The major difference between the 2-1/2" and 2-3/4" loads is CHAMBER PRESSURE, not the hull length. Sherman Bell did extensive testing some years ago and found that all other things being equal, hull length did not make any significant difference in measured chamber pressure. This was reported in a two part series published in the Double Gun Journal.

I routinely load low pressure 12 gauge loads in 2-3/4" AA, RST, or Federal (paper) hulls for use in my Dickson and Atkin 2-1/2" chambered 12 gauge guns. I have zero problems with doing so. SO, not withstanding the long held notion that 2-3/4" hulls raise pressure in short chambered guns, it is the LOAD PRESSURE that matters, not the slightly longer hull.

Good to know, I ordered some paper from RST. Great company to deal with.

The only real downside to using 2-3/4 in a 2-1/2" chamber is that it can hurt the patterns and increase felt recoil a bit. I have lengthened the chambers in several of my English guns and use 2 3/4 dram equivalent loads to keep from beating the old guns up.

quote:

Originally posted by lee440:
The only real downside to using 2-3/4 in a 2-1/2" chamber is that it can hurt the patterns and increase felt recoil a bit. I have lengthened the chambers in several of my English guns and use 2 3/4 dram equivalent loads to keep from beating the old guns up.

When loading the longer hulls for my short chambered guns, I err on the side of lower pressures. The factors are shot load, wad, powder type, and primers. In AA hulls (old style) am usually loading 1 oz. or 1-1/16 oz. loads using WAA wads or the Claybuster clone, 7625 and 209P Remington primers. This is a light, lower pressure load that performs well on birds and targets.

In the past I have altered the short chambers on a couple Brit guns, but I do not recommend it, since it takes the gun pout of proof and lowers the value. I like to keep my more expensive guns 'original' so they can be more easily sold when I reach the stage where I am simply too damn old to carry them around.

So I got to hunt the Cogswell. Used 2.5 paper with 1 1/6 shot from RST. I have to say I didn’t shoot real well! But I didn’t pattern it, just went hunting. I had shell split from brass to the end, mean anything?

quote:

Originally posted by tomahawker:
So I got to hunt the Cogswell. Used 2.5 paper with 1 1/6 shot from RST. I have to say I didn’t shoot real well! But I didn’t pattern it, just went hunting. I had shell split from brass to the end, mean anything?

I had that happen on a 10gague 3 1/2 inch magnum. It only happened once. I killed a turkey with that shell. I just shock my head at it.

I would call RST about it. I have run through a flat of 250 rounds this month of 2 1/2 plastic hulls. They have done well. I can’t shoot, so all misses are mine. The thing with clays s if you miss you get to pick them up and try again.

We went to a pheasant preserve, their final day of the year. Dad and I both had trouble pulling the trigger on hens. Never did that before! Our dog did well, had one spectacular retrieve of a wounded bird 150 yards away. Never would have found that bird without her. Very little recoil with the C&G and those loads. Highlight of the day, my son shot his first pheasant. He had a few misses this past season and was over the moon to connect. He is shooting a Lefever 20 gauge made in 1925. I think they are bonded together now!

Wonderful! You may know this already, but the Gold 2 on the rib means your gun was one of a matching pair!

It has a twin out there somewhere. What shot size were you sending the way of those pheasant?

Yes, if anybody know where #1 is I’m interested. 5 shot on the birds

quote:

Originally posted by tomahawker:
Yes, if anybody know where #1 is I’m interested. 5 shot on the birds

There is a dealer in the UK who does business as 'Matched Pairs". He is at Matched Pairs He connects people with the 'other gun' of a pair. You can register your gun there. I am looking for the no.2 gun for my Henry Atkin lightweight spring-opener and registered there.

Excellent info! Thanks Alec