Single shot shotgun muzzle question

[fox fire]

Thru the years I've seen quite a few older SINGLE SHOT shot gun barrels that looked like the very end of the muzzle had been swaged down just a tiny bit, this being said most are perfectly square.
At first I thought it mite be some old timers think'n they could hammer the end of the barrel in an effort to choke it down a little more so to tighten up the pattern some,Then the thought came to me that it may be something done from the factory since I've never seen any hammer marks & the bluing isnt scratched up.
 
Anyone have any food for thought ?? 

[charles p]

My guess would be an attempt to make a turkey shoot gun.

[fox fire]

Very well could be, was look'n at a Winchester 37 in .410 last week &  370 in .20 & both were done that way, since they couldnt srew out & replace the choke this "swaging" mite have been something they done.
 
Just a thought, but really dont know.

[james]

I've seen a choke tool that was used to constrict a barrel.  It looked like a pipe cutter with the cutting blade replaced with another roller.  The rollers were polished and I doubt if it would leave much of a mark. 

[Ranger99]

15-20 years ago, i read an article in
one of the gun mags about mossberg
making their barrels, and replacement
barrels for remington, etc.
they were telling how that when they
turned the barrel, a reverse sort of taper
was turned in, and that would be swaged
down even to leave a choke constriction
inside the barrel.
this was way back when mossberg was
mossberg, and not part of a corporate
umbrella-type thing.


maybe the same process was used on
the gun in question?

[gunnut69]

There are several ways to choke a shotgun barrel. They can be bored and that is common in european guns and some other high grade guns.. In this country the most common method is to simply squeeze the end of the barrel down to create necessary restriction..I've seen many Mossberg 500's with the end of the barrel slightly oval from the process. Dad said this concentrated the pattern verticully on the turkey..  Some old singles had their barrels made with a tapered bore,, which could then be cut to a specified length for the required choke i.e. 28 inches for modified, 30 inch for full. I have a device acquired many years ago that uses polished steel rolers mounted in a frame that can be tightened. They are set at a slight draft so that as turned and tightened they rotate off the end of the barrel. Some trully impressive constrictions can be achieved. There is even a method to choke muzzleloaders that still allows loading..that is commonly used now for high end clay target guns.  What you likely saw was likely the normal choke applied to most shotgun barrels. Anything that causes a reduction in the shot charge diameter creates the effect of choke boring..

[fox fire]

Thanks for the input gents, I somewhat figured it mite be something to effect of choking, its just the very tip end of the barrel & as stated very clean work.
 
Now I know...kind of.