Chokes for short bbl.

Discussion in 'Mossberg 500 Pump Action' started by Patch700, Mar 14, 2017.

  1. Patch700

    Patch700 .22LR

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    Hey guys , just wanted to touch on a topic that was brought up regarding using your HD rig for other purposes such as predator control or winged varmint shooting etc.

    The obvious problem one occurs is the lack of spread pattern control with an 18-20" bbl with Cyl bore. One option is to try and locate a bbl threaded for chokes that will match your mag tube.
    If you have an 8 shot tube those options become less without swapping mag tubes.

    The option I've chosen for a 500 / 8 shot with a 20" Cyl bore bbl is to have it reamed & threaded for chokes (accu-choke & win choke in this instance)

    One of the problems you can run into with a mod like this, is the barrel is too thin to allow for any material removal. However the 20" models seem to have enough with room to spare without having to go to a thinwall design.

    In any event, I've had the mod done and the cost was 130 bucks (Cdn) and came with a 3 set of chokes.. Can't complain there as the tooling to do it myself would have cost well over 250.

    Hope someone finds this helpful and a possible solution.

    IMG_2806.JPG
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  2. MikeD

    MikeD I'm Your Huckleberry Staff Member Global Moderator Forum Moderator "Philanthropist"

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    The following is what I was told by Rose Action Sports. The smith you use should be able to give you specs based on the type of chokes they install but this should give you a ballpark idea.


    The problem I encountered with mine is that once the choke was installed there was not enough material to hold the bead in securely.
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  3. Patch700

    Patch700 .22LR

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    Those numbers are exactly what my smith told me as well Mike so that is good news lol... This particular Bbl I mic'd and it came in at .857" so I opted for the winchoke tubes , also should I chose to do so I can run steel shot through it.

    And you are correct in that there is VERY little material left for the bead to thread into.. For those that are wondering, you are basically left with .020- .025" of material to get a bead threaded.. So not alot lol. Definitely need good thread locker and in a worse case scenario , mix up a small amount of 2part epoxy to the threads (will need heat to remove)

    IMG_2808.JPG
  4. Rossignol

    Rossignol The Original Sheriff Staff Member Global Moderator Sponsor Forum Moderator

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    What kind of winged varmints can you shoot in Canada or do you mean winged varmints as in waterfowl hunting?
  5. Patch700

    Patch700 .22LR

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    Within the boundaries of our own property we are allowed to hunt crows... There is no open season for them on public land however.
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  6. Rossignol

    Rossignol The Original Sheriff Staff Member Global Moderator Sponsor Forum Moderator

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    I gotcha. Sorry for the off topic question.
  7. Bobster

    Bobster .308 Supporter

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    What if you moved the bead inboard past the choke threads?
  8. Patch700

    Patch700 .22LR

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    Lol no worries at all.. We actually do quite a bit of predatory control on the farm here and truth be told its mostly in the name of managing the upland and waterfowl on the property. Crows are an absolute menace on egg laying species as are the coyotes.. We just like to give the upland and waterfowl a better chance to keep their numbers up as they have been dwindling.
    The coyotes can be so bad here at times that a good farm cat has used up most of his 9 lives in the first 48 hours lol.
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  9. Rossignol

    Rossignol The Original Sheriff Staff Member Global Moderator Sponsor Forum Moderator

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    Or what about a fixed choke vent rib and have that cut for choke tubes?
  10. MikeD

    MikeD I'm Your Huckleberry Staff Member Global Moderator Forum Moderator "Philanthropist"

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    Given the length of the barrel, 18.5, it really does not work for me. Given the contour of the barrel, the sight aleady sits to low for me and I shoot very high at 30 yards. I was talking to a smith at Williams Gun Sight and I plan to take it in to see if they can silver solder a base, around 1/4", with a bead on top or just install a front blade sight. I do not want a rear sight, this is just going to be used for turkey and HD.
    Last edited: Mar 14, 2017
  11. Conn 500

    Conn 500 .223

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    Bought one of those 20" Mossberg 500 barrels sold by CDNN when they were $55 with a cylinder bore and full choke. Think they're still like $55 or $60 at CDNN. Basically a Chinese pipe spray painted black to fit the traditional 500 set-up: 5+1. Ain't pretty, but sure is fun and hurls a mean accurate slug with an modified choke. For a 20" barrel with a modified choke and Federal FliteConrol buck shot it keeps a decent pattern out to 40 yards all things considered. The front bead sight is a bit cock-eyed, but for the price.............I've been popping clays with 8 shot and a skeet choke nearly as well as my 28" barrel. With the bantam stock and the 20" barrel, it has become my HD shotgun. Still have the 18.5" with the pistol grip, but I've grown fond of the 20" with the shorter butt stock.
  12. MikeD

    MikeD I'm Your Huckleberry Staff Member Global Moderator Forum Moderator "Philanthropist"

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    Stumbled on this base on Midways site and it is exactly what I was looking for. It's a police sight base for an 870.

    810698.jpg

    I've seen many barrels with that base but somehow missed when I was looking for DIY options...well until now. ;-D
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  13. Patch700

    Patch700 .22LR

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    That looks like a great option Mike. Do you happen to have a part# ?

    I've done a search on brownells and haven't found anything except the large blade type and that's not something i want for this setup.
  14. MikeD

    MikeD I'm Your Huckleberry Staff Member Global Moderator Forum Moderator "Philanthropist"

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  15. Patch700

    Patch700 .22LR

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    Just a quick update , took the 20" out today to do some patterning with various loads including my go to load for buckshot.

    Keep in mind these are shotshells that have served me well in various other shotguns and are what i generally keep on hand around the farm.. I did not purchase other brands as of yet however i plan to do so in the future.

    Regarding birdshot sizes 6 , 7-1/2 in lead(federal & winchester respectively)... no noticable difference in the first 10 yards going from cyl bore all the way to full.
    Where the choke choices showed their colors was beyond 20yds.

    Regarding birdshot sizes 3 &. 4 in steel (Kent gamebore & Challenger respectively).. same as above with a note that as expected the steel didn't like a tight choke (full) , mod showed the best results all the way to 30-40 yds.

    Regarding 00buck , there was a small difference going from imp/cyl to mod @ 10yds.. Essentially shrunk my pattern size from 9-10" at 10 yds with cyl bore to 5-7" payterns at 10 yds with the mod and full chokes.
    The buckshot also showed a good improvement at 15 & 20 yards , keeping all 9 pellets into a 14-15" circle at 20 yds.


    IMG_2819.JPG


    Will be doing more extensive testing at a later date at further distances as the wind was starting to come up badly so i opted to stop pattern testing anyways.

    Would I do this mod again? Yes , for my needs I am happy with the results... for somone who is solely using their short bbl for HD with an 18-20" cyl bore bbl I would say to save your money and spend it on premium ammo such as flite control etc if you are wishing to tighten up patterns.
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  16. Rossignol

    Rossignol The Original Sheriff Staff Member Global Moderator Sponsor Forum Moderator

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    ^^^that is beautiful!

    I have both a cylinder bore 20" and a choked 20". I use FliteControl in the cylinder as you suggest and it's good easy to 25-30 yards and even just a little further. The choked 20" gun is solid like a hammer to 40 and my longest shot on game is 45 yards. Patterns are still decent at 50.
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  17. Patch700

    Patch700 .22LR

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    Next time I'm in town I will definitely try some of the flitecontrol stuff in 3" if possible , but will also try the 2-3/4".

    I'm kind of curious how much difference i will see , would really like to also use this combo for a backup rig while calling in coyotes , mainly utilizing a rifle but keep the mossberg in the blind for when they come charging in.
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