Shooting modern 20g loads out of old Tobin 12g SxS

[green machine]

Looking to make a set of chamber adapters for my old Tobin. Non Damascus barrels. I'd like to be able to take it out for the odd round of trap, or possibly hunting. 2 1/2 inch loads are not readily available around here. On some quick calculations, the thrust of an 8000 psi 12g load is similar to a 12000 psi 20g load. Is the pressure difference an issue with the smaller shells?

 

[ninepointer]

I can't help ya, but your thread title almost made me fall out of my chair. I didn't read it fully and I thought you'd discovered a real unicorn! LOL

 

[OldSavage]

You could reload 2-1/2 inch shells

 

[Roalco]

You don't say where you are, but give KentGamebore a call at their Canadian distributor, they stock 2 1/2" 12 bore shells,and can help you out.
http://kentgamebore.com

 

[homslice]

I had an old Damascus 12 gauge that I used to put 410 though with an adapter. Never had an issue but never did any serious shooting with it either

 

[canvasback]

The barrels of your Tobin were never designed to handle 12,000 psi. That is for sure. Now, what happens to the pressure curve when you shoot using 20
gauge adapters I have no idea. Why not just shoot light 12s. Not that hard to find 2 1/2" shells. They just aren't normally in your neighborhood gun shop. Unless you live beside Epps. LOL

Kent often has them and they will ship. Same for Intersurplus. And you can often find Challengers at a variety of shops.

 

[sillymike]

Maybe 2 1/2" shells were harder to find back in 2014

 

[canvasback]

Maybe 2 1/2" shells were harder to find back in 2014

OMG, I missed that. Hahahaha.

 

[Londonshooter]

I don't want to call anyone a necrophile but....
Great, now I'm adding to it.

 

[bearhunter]

Frontier Outdoors, a banner advertiser has the adapters you're looking for.

12ga to 410, 20ga, 9mm, 357mag and 44mag.

These premade inserts could make many older side by sides, single shots more versatile.

What you need to be careful with is the receiver of your shotgun. Some of those older guns had quite soft receivers and may end up with cartridge impressions on their faces.

 

[Ol' Flinter]

They aren't cheap but a pair of Briley short inserts would likely be a safe option for the barrels....can't say how the receiver would handle the increased pressures though.... just another option.

 

[iron cat]

I have used my 20 and 28 gauge Briley Side Kicks for more than a few years in my vintage guns for trap and skeet, I have not noticed any listening of the actions . All the barrel pressure is where the inserts are .
One thing I do is make sure I take them out and clean the chambers after every outing .
I also only shoot 1/2 oz loads in the 28's and 3/4oz in the 20's
Cat