The following will show the installation and maybe pattern testing of a Poly-Choke device. "Poly" means many, (like polynomials for educated folks out there....or polygamy for those who like to count past 2 and don't mind factoring a "x" or two).....bad math joke sorry. The poly-choke is designed to give you options in the pattern your shotgun disperses depending on the situation you find yourself in. Out rabbit hunting in close brush? Turn it down to Cylinder...rabbit jumps and you don't pick it up right away? Crank it up to full and let loose.
Shown below is a "stubbed" poly-choke. "Stubbed" refers to the section of barrel that remains installed in the choke, how its installed I am not sure. It can be sweated on with solder (or jb welded on if somebody got lazy) OR it could be threaded on. The poly-choke was given to me by a gentleman from Texas who thought I could get more use out of it than he was. He did not know however how in fact the choke was previously installed. The point is this poly-choke was on a gun previously and removed, by cutting it off with a hacksaw with enough of the barrel sticking out so the next guy can remove it and reuse the choke which is what we plan to do.
|Remove outside sleeve.|
|Choke collet and barrel stub shown|
At this point we are needing to firmly secure the choke in a barrel vice to remove the barrel stub. The steel pipe shown opposite the choke will keep the clamping action from focusing on the center of the vice, it will instead focus it on the thick portion of the choke protecting the collet.
|With top vice sleeve in place the top bracket of the vice is replaced and secured.|
A little heat to see if solder or anything else comes out....some good old fashion torque on the stub with some shocking action and presto! The barrel stub turned out to be threaded into the choke....this revelation will require me to gain some more information on the thread pitch (which I am pretty sure is 40 TPI but want to double check) max and min barrel diameters and some other factors that may have to be taken in to consideration for the next phase of this project. The idea is to restore a 870 barrel back to having a choke, the vent ribbed full choke barrel met its demise when a few inches of its previous 26" barrel were removed for home defense use via hacksaw. Making the barrel effectively a cylinder choked gun, useless if you already have a riot barrel and need a field barrel which is what I am lacking currently.
|Stubbed portion of barrel shown un-threading from Poly-Choke.|