doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com 20 bore over chokes

I got my Union Fire Arms 20 ga., pump gun, up and running. Fit a second set of barrel with pump assembly and magazine to the gun. Went out to shoot a round of skeet with it. It was all or none as they say. More rifle than shotgun it seems. Had to bear down like I was shooting a .410. 23 ink dots with the longer barrel. So I put the shorter second barrel on and repeated the same score, even missed the same two birds. Proving its me, not the gun. Low six has ruined many a round for me.

I had measured the chokes quickly, when I first got it, but assumed my cheap bore micrometer had to be off. So I got out the CSP Custom Shooting Products bore micrometer after a good cleaning. Calibrated it and measured the bores again. No wonder there were a lot of ink dots. The shorter barrel, 27 7/8" was choked .040 and the longer 29 7/8" barrel was choked .040. Went back to the cheap set and that was what they told me as well but what I had refused to accept.

This was a 20 gauge not a 12. Who chokes a 20 that tight? Why? Were other early 20 gauge pump guns bored that tight, by other makers? I know makers put a lot of hype into print adds that said, "hit harder" and "killed further" but these chokes are way tighter than I expected. Perhaps before wads and shot protection, before hard or chilled shot, such tight chokes had a place.

Going to go to the pattern plate and then will get out a set of choke reamers and open up the extra set of barrels to a more sane choking. Maybe .015 for modified or .027 for extra full. Figure I'll leave the original barrel as is, but it will be nice to get a working barrel that I can shoot a few rounds of skeet or sporting clay's. Right now it might make a heck of a 27 yard line trap gun but not much else.

I think you hit the nail on the head with the last sentence of your penultimate paragraph. Soft lead of inconsistent and poor quality, with felt and cardboard wads, meant that shooters and gun companies favored chokes that are overly tight by modern standards.

Even today, Remington Gun Club loads (which are better than the cheapest promo loads) have been shown to pattern with 5-10% less density at a given range than premium hard shot target loads (like Remington STS or Nitro 27s). I can only imagine that 120 year old shell technology would also give up at least another 10% in density.

So to achieve a full choke pattern (70% of shot within 30� circle at 40 yards), but with shells that would throw a 50% pattern (an Improved Cylinder pattern) in a modern gun that normally gets 70% pattern, they had to greatly tighten down the choke.

Or, it could just be that choke boring was relatively new and they accidentally specified it too tight.

How about a couple pics of that little pumpgun, Jon?

I do't recall having ever seen one.

SRH

Hoooo....ha..ha....heee....haAAaa....

Good luck with the request.

Not helpful to the question, but
http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=484762
Union Fire Arms Company was incorporated in Toledo, OH in 1902 by George B. Colton, and was successor to Colton Manufacturing Company (1894-1902). Union Fire Arms Company continued supplying Sears and others with double barrels under the names Union Arms Company (c.1910), Illinois Arms Company (Sears) and Bee Bee Arms Company.

Note "Nitro-Steel" barrels less than pattern welded, and were likely Decarbonized steel



Here's one
https://www.gunauction.com/buy/5485787

These were made with Krupp barrels which is what drew my attention to start. Solid ribs were a real surprise. Production had to be near the early end, three digit serial numbers.

I�ll try to pm you a few pictures Stan. Joe can wait.

There is one good purpose for a tight as Dickens 20 ga. A boy's squirrel shotgun. Gil

My fully optioned Ithaca NID 20-gauge has .038" choke in the right barrel and .042" choke in the left.

Do you think your NID is a bit overchoked. That�s full in a 12. Extra full in 16 and extra, extra full in a 20. Might be approaching an obstruction in 28 or .410. Or is it?

Maybe we need to look st this differently. What is full choked in a 20? I know what the Briley choke chart says. But is that correct for guns built 50 years before wad design protected shot? I think .040, with hard shot and good wads is overkill. Might try a couple fiber wad loads to see if .040 makes sense in a 20.

Ithaca Gun Co., Inc.'s own barrel drawing goes with .026" for full choke in 20-gauge --



if my math is right!!