short chambers

[Harry Schlott]

Hello All,
Is it safe to shoot 2 3/4" cartridges in a 2 1/2" chamber?
Thanks

[John Knobelsdorf II]

It has been done. I have done it. Your results may vary. No internet stranger can tell you what will happen for you. Caveat iaculator

[Drew Hause]

Opinions vary.
Scroll down about 1/2 way here for several, and links to previous discussions on DoubleGun
https://docs.google.com/document/d/1...A/edit?tab=t.0

ONE study of modern loads in a 12 gauge showed an average increase in pressure of 700 psi. Please note there are NO studies regarding modern 16g and 20g loads, and that Parker chambers were typically slightly shorter than 2 9/16" for 16g and 2 1/2" for 20g. I had a 1924 20g Parker with chambers almost 2 3/8". It is likely the case mouth of 2 3/4" 7/8 oz. target loads entered the forcing cone as recoil was wicked, possibly explaining the previous repair of the cracked stock.

SO, if the question is regarding a 12g Parker, that has been evaluated by a qualified smith, with measurements of wall thickness at the end of the chamber, the answer is yes, using loads with pressures for which the gun was designed.
I would not use 2 3/4" shells in a 12g 2 1/2" chambered lightweight British or Continental game gun, and would NOT use 2 3/4" shells in a small frame 20g with 2 1/2" chambers.

Some nominally 2 3/4" 20g and 16g hulls are shorter, but components used by ammo makers change so it would require measuring a collection of empties.



Winchester Super-X 16g 1 oz 1165 fps 2023

[Craig Larter]

I do not buy a gun unless it meets Dr. Drew's recomendation:

For that reason I favor as MWT for pattern welded barrels:
End of chamber - .105”
Forcing cone - .100”
9” from breech - .045”
9” from muzzle - .025”

Factory original 20 and 16 gauge small frame guns with Damascus barrels may have a wall thickness of .090” at the end of the chamber (and Fluid Steel barrels slightly less); and .020” in the distal third of the barrel, making it critical to use loads that match the ballistics of shells originally intended for use in the gun.

[Harry Schlott]

That's terrific! Thanks Drew.