[Ulysses]

Are all 870, 1100 and 11-87 cylinder bore barrels true cylindrical from the end of the forceing cone to it's end?

I can't think of any good reason why they would NOT be true cylinder bore if that is what is marked on the barrel. I'm assuming you are referring to fixed choke barrels and not barrels that are threaded for screw-in chokes.

Why would you think that they might not be true cylinder bore? What is it that concerns you?

 

[Ulysses]

But the thing I wanted to know if a factory Reminton cylinder bore barrel is true cylindrical and has no backboring or recess choke.

Once again, I must answer your question by asking why you would think that Remington would resort to a recess choke in order to choke their CYLINDER barrels? If the barrel had a choke in it, regardless how that choke was obtained, it would not be a CYLINDER bore barrel. What someone does to a Russian barrel has nothing to do with what Remington does with their FACTORY barrels.

As for "backboring", that is a very vague and often misused term in today's shotgun terminology. If you have a particular barrel that you are interested in, the best way to find out if it is recess choked (a.k.a. jug choked) or "backbored" is to use a bore mic to measure the barrel all the way from chamber to muzzle.

I wish to confirm that a 28" Remington barrel cut to 26" is as good as a factory cylinder bore 26" one, pattern wise.

If the barrel is a Remington factory barrel that is marked "Cylinder" by the factory, then YES, cutting 2" from that barrel should have no noticeable effect on the pattern.