Friday, April 25, 2014

Polychoke: A throttle for your scattergun - part 2

Before I continue on with this Polychoke project some correspondence with the company has brought some information to light that I think should be shared here. First of all the Polychoke is best installed at the factory, as of this writing it only costs $65 for them to do it and it is what they do for a living. As I have learned from this project there is a lot more that goes into the installation of these than is thought from the get go. Second, the choke element that is the part that is threaded to the barrel comes in 3 different sizes I feel like few people know this and do not understand that they are also not marked with what size choke element you have. The diameter of your barrel determines the choke size you will need, something to keep in mind when purchasing a USED polychoke. You have to know what the internal diameter of the choke element is in order to see how it matches up with your barrel. There is a number stamped on the choke element, this has nothing to do with the size of the choke or what it goes to. Those numbers were a reference system the company used with the shops that installed the chokes.

More information on the polychoke and its installation may be made available as this project progresses. On with the project!

My goal with this project is to have a short(er) field barrel than the long full choke barrel I have now. This might not be the best balanced barrel when it is all said and done but it will be compact and better for my needs all around on my favorite 870 which I have grown exceedingly fond of in the last few years. The shotgun continues to impress me as to its versatility even though its not very economical in weight of ammo vs game harvested. I looked to polychoke when I realized this barrel was not going to pattern well without the help of some external forces. This post in the project will show the barrel, and the beginnings of the fitting process.

Shortened 870 barrel shown with practice stub from another barrel project threaded and test fitted with the Polychoke.

The Polychoke will add approximately 1.5" in length to the barrel, we will be keeping this in mind as we work making sure we maintain a 18" MINIMUM barrel length when we are all said and done, ideally you want to be 18" and some change over. Installing with high temp solder or welding the choke in place will make it permanent which is required by law to be considered part of the barrel.

Ready for turning and threading

The barrel as it started in the project. 

Long vernier calipers can come in handy when laying out minimums. Making sure to keep in mind its best to be over by 1/4" with shotgun and rifle barrels.

Turning to nominal thread diameter everything looks good here!
I somehow lost pictures of threading the barrel at this point, and then I realized that upon test fitting I had messed up. The live center I used was in poor shape and I think it cause the barrel to be just a fuzz off......sooooooo we need set the barrel back 1/2" and try again. Not a big deal, we still have plenty of barrel to work with.

Hey look threads! WAIT WHAT ARE YOU DOING WITH THAT HACKSAW!! to your kids about hacksaws before somebody else does.....

No comments: