doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com 12ga bore diameter

Good afternoon.
I am gearing up to shoot my Ithaca Lewis gr4 with stars and strips damascus barrels. I brought the bore gage home to check wall thickness and was surprised at my findings 6" from the muzzle. I think the barrels were 30" F/F cut down to 26". They did a good job but it is a shame.


Nominal bore dia
left barrel .718
right barrel .708

wall thickness
left .028
right .035

od at 6"
Left .774
right .778

choke
left .0045
right .0025

Sure seems tight to me given the .729/.730 dimension I see all the time. I know I'm not still in the chokes because they measure within 1 or 2 thousandths on the chamber end. Any thoughts before I hillbilly proof this thing?

Thanks,
Ithaca1
Bill

Most of my pre Minier, Ithaca 12's have smaller than standard bores The tightest being .710/.711. But the small ones also have heavy/thick tubes and Full/Full chokes. I shoot 2-1/2" Poly-Wad Vintagers in all of them and have no issues.

Thanks John for the note. That is what I had expected, but wanted to hear it from someone who has seen it and done it.

Best,
Ithaca1

You could probably jug choke the barrels.

It appears you measured the bore diameter and subtracted from O.D. at 6 " from the muzzle, then divided by 2 to figure the wall thickness. that is incorrect because O.D is often not concentric with the bore. better have some one with a regular barrel wall gauge do the measuring for minimum wall thickness before decide what to do..

I don't want to tell you how to proceed here, it's your gun and you assume all risks.

It would appear though, that you've determined the barrels have not been honed. We're sure there's not a layer of lead in there, right?

If they've been struck down externally is another matter, and while that would be cause for concern if it could be determined by accurate wall thickness measurements, I'd be more concerned with chamber length.

If I found original chambers... I'd be happy. If not... well... tube it or hang it.

The concept of 'hillbilly proofing' is as distasteful to me as actual English style re-proofing. It serves no purpose except to unnecessarily stress the entire gun.

Why destroy something for no reason?

Thanks for the feedback gentlemen. The barrels were checked and browned years ago by Keith Kearcher. I have not shot it since then and wanted to see if the barrels had any choke. That is when I noticed the small bores, and the reason for my question.

Cherrybomb,
You are correct. Poor assumption on wall thickness.

Shotgunjones,
My proof will be to fire a box of Gamebore split between the two barrels on the far side of a pine tree. I agree, no added stress required.

Will post pictures of the results.

Thanks again
Ithaca1