Creating a Modern 9mm Rimfire Shotgun (Centerfire)

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  • Last Post 05 February 2014
jimwill48 posted this 15 September 2012

For no other reason than I think it would be fun and maybe of limited value as a close in garden style gun I would like to create a modern 9mm rimfire style shotgun but in centerfire. Was thinking or trying to fine a old wore out .22 Hornet barrel for my NEF frame and have it bored out to a smoothbore .357” and then chambered for a .357 Maximum case. The old 9mm rimfire, shot 1/4 oz (110 grain) load of shot at appox. 600 fps. I was thinking of increasing this to a 1/3 oz (145 grain) load of shot at appox. 1050 fps. which seems to be easy to do.

I know that I can shoot a 2 1/2” .410 and have several of these. I just think this would be a great in-between thing and rather unique and fun. Of couse the big issue will be in obtaining the barrel and having it fitted to my action and bored and chambered. Any idea's on who I could get to do this at a price I could afford?

Anyway, what do you all think? .>

James

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CB posted this 15 September 2012

Thompson Center used to offer a 357 mag “Hotshot” cartridge. Unfortunately, these are pretty much long gone, but there should still be loading data available. These were shot through rifled barrels, but they had straight chokes at the muzzle to break up the shot capsule, and to slow or stop the spin imparted by the rifling. If you revisit this idea, you may be able to use a 357 mag or 357 max barrel and save yourself some machining costs. None of this may be of use to you, but this is the first thing I thought of when reading your post, so I thought I'd mention it. Creative loading of a single shot .410 would work too, but wouldn't anywhere near as much fun for you to accomplish.

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32ideal posted this 16 September 2012

Never fooled around with the smaller cases but I did modify 444 Marlin cases to fit the Ruger 45LC SA revolver cylinders full length, then ream inside to .413” using a Letter “Z” reamer to base, then load with shortened 410 wads (which ever wad it was is I used had a very shallow cup towards the powder, 1/16” or less, other wads did not work well) over 4756 or red dot, don't remember the loading data as this was in the late 70's, but I do remember getting almost 1/2oz of #8 shot in them, worked great on Snake's and close up Northern CA Gray Squirrels.

32ideal

PS: Also modified 308 cases same way to fit the 45acp Ruger cylinders full length!

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Ed Harris posted this 16 September 2012

Colrain can produce on special order smoothbore barrels in any of their standard blackpowder rifle calibers. They make a .36 which might do for your purpose.

Phone: 814-632-7513

Address:

Colerain Barrel Co.

3820 Spruce Creek Rd

Spruce Creek, PA 16683

E-mail: [email protected]

http://colerainbarrel.com/smooth_bore_barrels.html>http://colerainbarrel.com/smoothborebarrels.html

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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shjoe posted this 03 January 2014

i had a smooth bore NEF/HR 357 mag barrel made up as a garden gun. shoots a load of #7 1/2 shot over bullseye with cardboard wads. i use either egg seal or clear nail polish to seal the end of the cartridge. patterns nicely out to 20yds. great for handling garden pests without blowing up the veggies. also have a 3 ball (OO buck) load which is interesting out to 15-20yds. shots normal 357 mag loads also. they shoot to point of aim at 20yds, but key hole.

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JSH posted this 03 January 2014

How does a round ball key hole?

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R. Dupraz posted this 03 January 2014

How does a round ball key hole?   ':D' 

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pat i. posted this 03 January 2014

shjoe wrote: shot normal 357 mag loads also. they shoot to point of aim at 20yds, but key hole. I think you guys missed this part.

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shjoe posted this 03 January 2014

correct, pat i. the 3 ball loading typically places 2 round balls about 2” apart at 20yds with the third being a flyer 8-10” away. only critter to fall to this loading so far was a slow moving porcupine. the third ball barely fits, may try using 2, O buck rd balls instead. also have substituted #4 shot which carries a bit more energy further out. a reasonable test for effective shot energy is the amount of shot pellets penetrating a soda can at a given distance. for example, i have counted 4 #4 pellets perforating a soda can at 20yds with this loading. enough for garden pest control at that distance. my 10ga muzzleloader with 90grs FFG and 1 1/2 oz of #4 shot will put 7-8 pellets through a soda can at 50yds (my turkey load). strictly a numbers game with a shot load. best, john

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w-d-s posted this 05 February 2014

shjoe, where did you get the extra barrel made up at?

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Ken Campbell Iowa posted this 05 February 2014

chips cost money ... i would look into an old worn-out ( cheap/free ) 35 remmy barrel.. it might clean up with a 0.362-0.364 reamer, which would work with a 357 mag or max brass .

heh heh, when you getter done, we expect to see a report on shooting very small ( 35 cal ) deer ( deer mouse ? ) slugs .. maybe mini Lee pellet rifle design ..

cheap butt ken

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shjoe posted this 05 February 2014

w-d-s: i had a NEF 357 mag barrel bored out to 357 smooth bore and an extra 30-06 barrel cut/rechambered for 32 acp. added a scoped 223 barrel for critters who dont come in as close. state line gunshop 603-878-2854

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