Let’s chop a shotgun barrel

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  • Magdump

    Don’t troll me bro!
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    Dec 31, 2013
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    Wanted to convert another old Mossberg 500 12ga hunting shotty into a security 12 but guess what, there ain’t no barrels online. I looked. Couple places said they had some, but they lied. Back order twilight zone.
    Had some old plain take offs (pretty dang old) from a few 500’s with steel safeties (told ya) that I’d already reblued and put up. Two 28in modified choke and a 30in full (which I elected to keep intact due to being a little harder to find)

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    Keeping in mind, I wanted them to take the place of a 18.5in security barrel, I measured twice. Then I placed a straight edge on top to mark a spot for the bead, using the original bead as a landmark for....top (dead) bead center and knocked a punch mark in it for the pilot bit. All good, cut it slowly (cut a second, cool a second) with the chop saw. A hack saw would do fine if you take care to square everything up. A tubing cutter would likely not work well, but might be the ticket for marking the barrel squarely for the cut.

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    Then a drill and cone shaped abrasive stone for the inner and I made a plug for the barrel so I could spin it with my hand drill while trimming the outer edge of the cut and bevel the muzzle.

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    Little blue right quick.

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    Drill the new bead hole.

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    Mossberg 500 beads have 5-40 threads. They also have a 5/32 inch hex shoulder built in. If you wanna salvage one like I did, briefly put the torch on it and it’ll break free with the socket just using finger power. Be careful tho, it’s hot.

    When using a tap this small, be aware that it’s apt to break with very little pressure, so cutting oil of course and once you get it going and it starts to bind, reverse a half turn, then turn forward til it binds again, then repeat. Run at least half the tap, unless it hits the other side of the barrel first.

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    I like red loc-tite. One drop and tighten the bead in the new spot. A tad tighter than finger tight. I used a 1/4 inch drive but babied it.

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    And that’s all there is to it. I have about 45 minutes in the entire job.
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    Last edited:

    MOTOR51

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    What are you using to ensure the cut is square to the bore?

    If it’s free from burrs I don’t think it would
    Make much difference if it wasn’t perfectly squared. I might be missing something though.


    Sent from my iPhone using Tapatalk Pro
     

    Magdump

    Don’t troll me bro!
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    If it’s free from burrs I don’t think it would
    Make much difference if it wasn’t perfectly squared. I might be missing something though.


    Sent from my iPhone using Tapatalk Pro
    I don’t want it to look TOO MUCH like a home job. The chop saw has a vise and you can check the cutting wheel with a square..
     

    MOTOR51

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    Chop that thing with a dull hacksaw and rock on lol


    Sent from my iPhone using Tapatalk Pro
     

    DAVE_M

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    I don’t want it to look TOO MUCH like a home job. The chop saw has a vise and you can check the cutting wheel with a square..

    I'm just trying to figure out a way to do it with the 30" 870 barrel I have. It has a taper to it. I don't have a lathe, so anything I do will be a DIY project. I figured I would ream the end by hand, but want to ensure it's cut square. Supposedly Brownells makes a tool for the job, but I haven't looked into it.
     

    Bangswitch

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    I'm just trying to figure out a way to do it with the 30" 870 barrel I have. It has a taper to it. I don't have a lathe, so anything I do will be a DIY project. I figured I would ream the end by hand, but want to ensure it's cut square. Supposedly Brownells makes a tool for the job, but I haven't looked into it.

    You could make a series of measurements from the muzzle down. Make marks all the way around the barrel. Then you could cut a little at a time carefully cutting on every mark until you removed the excess length then you could smooth the muzzle a file, reem the bore, and re-smooth the muzzle with Emory cloth.
     

    Bangswitch

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    Use a pipe cutter and ring the barrel a couple of times for a straight line, the cut right past the mask, finish up with a grinder to mark

    Yup
    Post #1

    I actually have one by Rigid that cuts stainless but no reason to try it when I have a chop saw.

    That sounds great for a straight barrel but a pipe cutter is going to want to walk down (path of least resistance) a tapered barrel and try to create a spiral inside of a circle. You might apply enough pressure to the pipecutter and make it cut straight. I’ve never tried it.
     

    Magdump

    Don’t troll me bro!
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    That sounds great for a straight barrel but a pipe cutter is going to want to walk down (path of least resistance) a tapered barrel and try to create a spiral inside of a circle. You might apply enough pressure to the pipecutter and make it cut straight. I’ve never tried it.
    I haven’t taken a micrometer to the length of barrel that I removed, but I’m pretty sure there’s either no external taper or not enough to make any difference at the section that I cut. I understand the principle but don’t think it would be an issue here. I can try my Rigid on the section that I cut and see what’s what tho. For what it’s worth, I have seen some cutters spiral, as you say, on harder material that is perfectly uniform.
    As I mentioned before, a tubing cutter would make a good guide for cutting, but considering the method it uses to cut, I’m not sure I’d want to make the cut with one even if it would do the job, due to the deforming it would likely cause at the cut.

    EDIT!!
    I can’t believe how easy it cut this barrel. I rung the barrel about 50 times or less while turning the knob about a quarter to half turn every couple rounds and it went right through with very little effort. As predicted, there is a build up of steel that creates a raised lip in and outside the barrel. This could easily be removed with a little hand trimming as suggested earlier, I like my method for ease and uniformity. Also, this particular cutter has a hardened cutting wheel intended for stainless and other steel tubing, but as easily as it made the cut, I have no doubt that lesser cutters might also get the job done.
    Anyway, no doubt about that being a square cut.
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    Last edited:

    gwpercle

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    Use a pipe cutter and ring the barrel a couple of times for a straight line, the cut right past the mask, finish up with a grinder to mark

    This is what I did . Bought a brand new, good quality , pipe cutter ( I asked a plumber for a good brand name) the cutter was very sharp and hard and hadn't been dulled by any use .
    Wrapped masking tape around barrel so wheels wouldn't mark the barrel and very slowly made very light cuts all the way around until the cutter cut through the barrel .
    Chamfered the inside and outside of the barrel , smoothed up cut with a fine flat file and finished up with wet-or-dry papers and cold blue .
    The new Pipe Cutter did a nice job and didn't require a lathe or expensive equipment .
    Gary
     
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    Bangswitch

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    I haven’t taken a micrometer to the length of barrel that I removed, but I’m pretty sure there’s either no external taper or not enough to make any difference at the section that I cut. I understand the principle but don’t think it would be an issue here. I can try my Rigid on the section that I cut and see what’s what tho. For what it’s worth, I have seen some cutters spiral, as you say, on harder material that is perfectly uniform.
    As I mentioned before, a tubing cutter would make a good guide for cutting, but considering the method it uses to cut, I’m not sure I’d want to make the cut with one even if it would do the job, due to the deforming it would likely cause at the cut.

    EDIT!!
    I can’t believe how easy it cut this barrel. I rung the barrel about 50 times or less while turning the knob about a quarter to half turn every couple rounds and it went right through with very little effort. As predicted, there is a build up of steel that creates a raised lip in and outside the barrel. This could easily be removed with a little hand trimming as suggested earlier, I like my method for ease and uniformity. Also, this particular cutter has a hardened cutting wheel intended for stainless and other steel tubing, but as easily as it made the cut, I have no doubt that lesser cutters might also get the job done.
    Anyway, no doubt about that being a square cut.
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    Nice that’s about as good a one could ask for a lathe would we the only way I see improving uniformity.
     

    jdindadell

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    That sounds great for a straight barrel but a pipe cutter is going to want to walk down (path of least resistance) a tapered barrel and try to create a spiral inside of a circle. You might apply enough pressure to the pipe cutter and make it cut straight. I’ve never tried it.

    If you are cutting on a mild taper you can use tape to build up the smaller "side" of the taper so that the pipe cutter can "track" true. Metal HVAC tape is handy for this as it does not squish.

    I have used a pipe cutter with great result to mark shotgun barrels, then used a hacksaw just past the line, and then filed up to the line to get a nice square end. Lightly chamfered the inside and outside in the same manner as magdump mentioned.

    This only works on non vent rib barrels, of course. I have removed the vent ribs on many shotgun barrels, not too bad of a job.

    I have also used a pipe cutter to trim down the mag tubes on shotguns, and to trim down those plus 5 extensions down to match specific length barrels. Pipe cutters work well on tubes, just be mindful that excess pressure may slightly shrink the tube at the cut area.
     

    Magdump

    Don’t troll me bro!
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    Dec 31, 2013
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    Here is my 870 I chopped in a chop saw to 18.25* just beyond the rib after the 18* minimum. I had a local machine shop bore and tap it to accept the factory choke.

    https://imgur.com/a/akZq2P2

    Oh yeah! That looks like a pretty decent tractor gun. We had an old beat up savage Stevens pump that brought home a lotta cottontail and so forth come bush-hogging day. Had a scabbard mounted on the hood that worked out well.
     
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