Eastern Arms 410 single shot . 2.5" or 3" shells?

Lazyshooter

Does anyone have one of the single shot, break-open Eastern Arms 410 (model 1929)? shotguns, and know what length shells this takes. Years ago, I shot one, with the 2.5", but ran out, and locally they only had 3", so I tried the 3", and though the shotgun closed a little harder, it did close, and fire the 3" shells, with the associated increase in recoil. I fired about a half dozen of the 3 inchers, and am wondering if it was made for them, and if I could have damaged the gun, if I used the longer shells?

If I remember, there is a ridge in the chamber, (don't have the gun with me now),but I tried measuring it one time with a small metal rule, but I really couldn't see or feel if the end of the rule was touching this "ridge" in the chamber to give me an accurate measurement. If anyone knows a better way to measure the chamber, let me know.

b.goforth

the eastern arms 410 model 1929 were actually manufactured by savage/steven and sold by sears roebuck & co. they were chambered for the 2 1/2 inch shell until about 1936/37. chances are this one was originally chambered for 2 1/2 inch shells. i would discontinue firing 3 inch shells in it until the chamber length was checked by someone qualified.
bill