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Full choke to modified?


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I just bought a used S-20 built in 2001. I has a few issues with it but I'm working on getting them fixed.

 

I took it out to pattern it and it appears to have a fixed full choke, a very tight pattern compared to my 1187 20 gauge with an Improved Cylinder. I was wondering if cutting back the barrel a little at a time would get me a modified pattern or at least loosen up the existing pattern a little. Has anybody done this? If so, how much of the barrel should I remove? I don't want a cylinder bore. I have plenty of barrel to work with, its a 22" non threaded.

 

Thanks

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Mine at 18.25 is Cyl.Bore. so I'd say, less than that! :) My 2001 is .615" diameter. I'd cut back a 1/4" at a time until I hit the proper constriction compared to a .615CB. IMHO

 

 

 

 

Thanks for the reference. That is what I am thinking as well, I measured mine at the end of the barrel and its .577

 

The barrel has a gradual taper to that full choke constriction so I need to find that sweet spot to cut where it mikes out to .602-.608...that will give me what I'm looking for.

 

What about refacing/recrowning? Is that necessary on a shotgun barrel?

 

I was planning on sending the gun out to be cut and threaded anyways, so if I screw this up its no big deal.

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don't use a pipe cutter to cut the barrel. you'll end up with a circular constriction around the muzzle. it's ugly and affects patterning.

 

thanks...so just tape and a hacksaw?

 

I figured out a way to tell where I need to cut! One of my friends is going to machine me a 1" cylinder made of aluminum that is .600 in diameter (20 gauge modified constriction) I'm going to drop it into the barrel and it will stop at .600 showing me a general area where the taper begins.

Edited by Arnisandyz
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  • 2 weeks later...

sorry, haven't checked in for a bit.

 

I did this very thing on a S12. I did the cut and measure method you considered to start with, but I like the idea of the plug giving you a better mark.

 

For me, I ended up cutting ~.75 inch (done in two cuts). The end wasn't exactly flush/square, but I wanted performance and am pretty famous for not regarding performance. I used a chop saw, didn't have patience for a hack saw. I thought it might take 8 to 10 trial cuts. Worked exactly as I'd hoped, pattern went from being a extremely tight to ~modified.

 

GL

 

After a bit, I had my gun at a smith, and they cut the end flush and threaded it for chokes to gain a bit more flexability.

Edited by kmoore
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