How to tell if you have modified chambers ?

[Milton Starr]

I was hunting with my bonehill today and you know how the rst 10 ga shells have their white logo on them ? well they leave white residue in my chambers where the chamber should stop . but when I look down the barrel the chamber goes another 1/2" or possibly 3/4" more it seems . I'm thinking someone lengthen them to 3.5" years ago , its a thick walled gun but still . I have some 3.5" 10 ga shells laying around so I just dropped some in the barrel and they slide in smooth as silk . I dont have a chamber gauge so is there any way I can tell for sure ?

[Big D]

Milton - I would assume that the 3 1/2" shells are in fact about 3 1/4" unfired. To use your measurement method, I think you should try to put a fired shell in the chamber. If it still goes in easily, then it would seem that the chambers are in fact 3 1/2"

[Milton Starr]

well I opened one of the 3.5" shells and it slide right in both chambers . I will get a picture after the original chamber there is discoloration the metal looks newer

[Milton Starr]

the chambers are one color thens there a grey area after them then the bore

[wayne goerres]

Milton You can pour a chamber cast using parafine. I do it all the time. Just lightly grease the chamber and make sure you get it full all the way. As it cools you will have to add parafine. The trick is to let it cool and harden for a hour or so and then nock it out and throw it in the freezer for about an hour. That will let you handle it for long enough to get your measurements. By the way try not to pour it on the outside of the barrels. Makes a real mess. Take a set of calipers and set them at .835. Slide the cast into the calipers until they just touch the parifine. Slightly rotate the cast to make a light mark. Then you can measure the lenth.

[Cold Spring]

Milton, just for info ..... unfired 10 gauge - 3-1/2" shells (either vintage papers or older & modern plastic) will not fully chamber in factory-original Ithaca NID Super 10's that were made for American 2-7/8" shells. I have tried it on multiple Ithacas. Shells will stick out of the chambers by about 1/4", cannot be forced in with finger pressure, and will obviously prevent the barrels from closing. I don't know about Bonehills or other makers but I wouldn't be surprised if your chambers had been lengthened for 3-1/2 inchers.