Chamber wall thickness

[MC1952]

My 20 ga Fox AE was originally chambered at 2 1/2”. I had the chamber wall measured and found it had been rechambered to 2 3/4”. The chamber wall thickness is .085. I’m assuming the original owner shot many 2 3/4” shells out of this gun but I’ve never shot anything but 2 1/2” RST’s.
What’s the consensus here on that? Is that too thin for modern 2 3/4” shells or should I just stick to RST’s?

[Sporrns]

Hello Mike - I just got finished measuring two nearly identical guns to yours, both A grades, one chambered at 2 3/4", the other at 2 3/8" in preparation for selling both. These guns are 630 SNs and 4 years apart in production (1917 vs. 1921). I have no way of knowing if the earlier gun with the 2 3/4" chambers has had them extended, but given the oft-quoted "standard" chamber length of smallbore guns of that era at the 2 3/8" dimension (for use with 2 1/2" shells), they probably were.

FWIW, the minimum barrel wall thickness as measured with a Hosford gauge for both guns is .030." The barrel wall thickness measured at a full 3" from the face of the barrels at the breech (e.g, at or beyond the beginning of the forcing cone) for the 2 3/4" gun is .085", while the measurement for the 2 3/8" chambered gun taken at the same distance is .110", which further indicates to me that the 2 3/4" gun probably had the chambers lengthened.

I've shot both guns; the 2 3/4" gun using standard target loads and the 2 3/8" gun using only RST 2 1/2" shells. As often said, I would be more concerned about damage to the stocks using more powerful ammo in the 2 3/4" gun or longer shells in the 2 3/8" gun. Hope this info is useful to you, Kevin

[MC1952]

I’m not worried at all about the stock cracking. I had this one restocked. But I would like to shoot something less expensive than $20 a box RST’s.

[Sporrns]

Wally World Winchester or Federal 100-packs (4 boxes ea.) are now working out to c. $10 per box in either 12 or 20 gauge. Kevin

[MC1952]

Wally World Winchester or Federal 100-packs (4 boxes ea.) are now working out to c. $10 per box in either 12 or 20 gauge. Kevin

I’ve got 8 cases of 20 ga RST’s in 7 1/2 and 8 shot.
But I also have 15 cases of 20 ga 2 3/4” target loads that I’d rather be shooting up at targets.
So if everyone thinks .085 is safe I just might give them a try.

[MC1952]

OK. I’ve still got all my fingers…
I took that old Fox to the clays course. I shot 25 rounds of RST’s and then shot 50 rounds of 2 3/4” target loads. No issues at all. Recoil seemed to be about the same and opening and ejection was fine.
I know that recoil isn’t an indicator of pressure but there didn’t seem to be much of a difference when shooting. I’ve got enough 2 1/2” RST’s for many years of hunting but I’m not worried any more about using modern target loads. I’ll stick with 7/8 ounce loads at no more than 1200-1250 velocity.

[Jeff S]

OK. I’ve still got all my fingers…
I took that old Fox to the clays course. I shot 25 rounds of RST’s and then shot 50 rounds of 2 3/4” target loads. No issues at all. Recoil seemed to be about the same and opening and ejection was fine.
I know that recoil isn’t an indicator of pressure but there didn’t seem to be much of a difference when shooting. I’ve got enough 2 1/2” RST’s for many years of hunting but I’m not worried any more about using modern target loads. I’ll stick with 7/8 ounce loads at no more than 1200-1250 velocity.

I'm guessing that I have shot 4-5 cases of 2 3/4", 7/8 oz, 1200 velocity shells through my 20 ga. Sterly.

[Stan Hillis]

I sent my 20 ga. Philadelphia Fox SWE to Dean Harris and had him lengthen the chambers to 2 3/4”, like yours is, about 5 years ago. I spoke with him before sending it to him and we talked about wall thicknesses before and after the work. I use 1 oz. factory loads in it, at 1155 fps, because that’s what regulates the barrels. Lighter loads crossfire badly.

I have zero concerns about the loads I use in this gun.