Arnisandyz 0 Posted July 31, 2010 Report Share Posted July 31, 2010 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 Quote Link to post Share on other sites
SaigaNoobie 66 Posted July 31, 2010 Report Share Posted July 31, 2010 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 Quote Link to post Share on other sites
Arnisandyz 0 Posted July 31, 2010 Author Report Share Posted July 31, 2010 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. Quote Link to post Share on other sites
SaigaNoobie 66 Posted July 31, 2010 Report Share Posted July 31, 2010 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. Quote Link to post Share on other sites
Arnisandyz 0 Posted July 31, 2010 Author Report Share Posted July 31, 2010 (edited) 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 August 4, 2010 by Arnisandyz Quote Link to post Share on other sites
kmoore 3 Posted August 11, 2010 Report Share Posted August 11, 2010 (edited) 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 August 11, 2010 by kmoore Quote Link to post Share on other sites
Arnisandyz 0 Posted August 11, 2010 Author Report Share Posted August 11, 2010 Thanks. IIRC I cut very close to .75 as well. After some grinding and filing to get the muzzle square I ended up with .608 (close to light modified or IC for a 20 gauge). Should be perfect but I haven't patterned it yet. Quote Link to post Share on other sites
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