Rifled Ithaca Question

[sffar]

Shotgun Aficionados,
Some years ago I bought an Ithaca 87 (37, really) 12 ga with a rifled 20" and ribbed barrel set.
I don't see myself using a rifled slug barrel, and would prefer a smooth bore for buckshot and slugs. It would make a good house gun, with it's plain Walnut stock and parkerized finish it'd be like a police gun. For any deer hunting I'd do around here a smooth barrel would probably be just fine. Thing is, Id have to backbore it, so it's have about a .733 or .734 (current groove depth) bore and cylinder choke at minimum. Would a slightly overbored 20" slug barrel cylinder choked serve well for buckshot and slugs, or would there be issues?
Obviously it'd be better just to trade for an identical barrel that's smooth, but haven't encountered one yet.
Sam

[sffar]

Thanks for the tip, Ithaca Gunner. For a long time they weren't selling the home defense barrel separately, so I'll check that out as an option. Still, having my barrel, which I like at 20" and which has sights already, would cost a bit less than the new barrel to back bore and remove the rifling. I do wonder about the slightly oversize bore that would produce. Would a .004 overbore effect the shooting of slugs and buckshot in any particular way, good or bad?
Sam

[sffar]

My barrel measures about .874 o.d., .733 in the grooves and .721 on the lands. So a smooth bore of about .733 or .734 could be made, I think, with this barrel. It would be 20", have sights, the lug would be in the right place and would remain factory parkerized. Thing is, though it's sort of a shame to remove the rifling, it seems more versatile to me, and I don't really need a "long range" slug only gun. I believe there's enough metal to add screw in chokes afterwards if it seemed worthwhile, though that'd add some expense for sure.
I'm inclined to want to shoot buckshot and roundball out of it, and I'm just not sure how the slightly over spec unchoked bore would likely work for the purpose.
Sam

[35remington]

Overbore will have no significant blowby. Remind yourself that some companies regularly overbore their 3.5 inch 12's to 10 gauge to produce more favorable characteristic with shot and also that modern overpowder shotcups obturate to fill the gap with their plastic skirts. These 12's have a lot more overbore than you are planning on, which is only five thou or so. Some of these 12's are forty thou plus overbore.

In terms of slugs some effect may be had depending upon whether the factory slugs swage up to fill the barrel or no. Theoretically obturation takes up some of that gap....and anyway you aren't big on slugs that much anyway.

I myself would want to have the rifled barrel but then I have a use for it and you don't. At least price some more Ithaca smoothbore barrels before you make your decision, and decide if a finish variation between receiver and (replacement) barrel would bother you or not. If it would, and you can't find a replacement at a price that will suit you, modify away.

To some extent if you cast your own slugs and roundballs and factor in choices in wad selection you can account for the extra five thousandths of an inch with no problem. In other words, especially if you cast your own, another five thou of bore size won't doom you.

[hubel458]

Our super sabots would work in that rifled gun as they are a little
oversize and you can cast or buy 58cal slugs for the sabots cheap.Ed.

[sffar]

Thanks for all the good advice!
I have several shotguns, and would like to either find a way to put this one to good use, or just sell it. One thing I don't have is a handy buckshot/slug gun, so the backboring seems like a good option if the slightly larger bore would work well. For about $165 I could have that done, while a new barrel from Ithaca, set up the same way would likely be about $300 when all is said and done. I am looking for a used barrel, though the Ithaca DS smoothbore barrels are also pretty much designed to work best with slugs as Ithaca Gunner pointed out on another thread, and that'd likely wind up $125 or so, and be 2 3/4" where my receiver will do 3". It is a shame, somehow, to remove rifling from a perfectly good barrel, but it does add a bit of versatility.
Sam