Please indulge my ramblings for just a minute so that yall can see my "whys" and "whats" for my little project.

I have a Remington 1100 that I have two barrels for (a 30 inch full and a 26 inch imp cyl).  Currently I plan on converting this gun into more of a "home defence" type gun...well that and I love to tinker with stuff.  Right now I pretty much leave the 26 inch barrel on all the time to bust clay birds and the 30 hasn't been on in probably two decades or better.  So I order up the parts I'm going to be using for the build...SpeedFeed 3 stock, 2 shot mag and new front and rear fiber-optic type sights for the ribbed barrel, and I am ready to get things put together.  Now for the question at hand.  I plan on cutting the 30 inch down to 18 inches and I would like to leave that guy on for most of the time.  So if I want to go shoot some clays with the 18 incher, would I need to put a choke in the tube or would it be fine as is?

Depends on how you define shooting "some clays". I assume you mean for backyard type recreation, etc. You will have a cylinder bore after you have the barrel cut. That will be fine for recreational skeet or the backyard thrower. You wont be able to shoot a long game like trap, FITASC or sporting clays with it.

yea, just some good ole backyard fun shooting.  nothing serious.

It would be fine for a bit of fun on close range clays. That's about it.

A screw in choke is often overlooked on Tac/HD SGs. I think it is a great addition. It allows you to tighten you tighen your pattern to suit your needs.

I have a 1100 with a 30" Full bbl cut to 18". It is threaded for Remchokes. I use a Compensated Mod choke (unsure of the brand). It patterns a lot tighter than a Cyl bbl. It's fine for clays but I usually switch it with a 30" full bbl.

F421,
Are you sure your cut-off is Rem-choked or is it threaded for Colonial Chokes, etc.?

I have an 870 threaded for Colonial/Tru-choke/Baikal.

My 1100 is definitely different. The thread is a lot finer on the truchoke.

It could possibly be Winchoke.

Tooling is only commonly available in tru choke, rem choke, or winchoke so must be either rem or win.

Pic-