h@r centerfire to rim fire

[normks]

It has been few months back I bought a broken a h&r topper shotgun stamped cap-chur powder projector.
turned out to be a tranquilizer gun of sort had a broken hammer . fixed the hammed with a new one made me a stub and drilled it off center and screwed a 17 call barrel chambered it in 17 win super mag and had a successful test firing

 

[SEK_22Hornet]

Hi Norm - looks pretty good! I have a similar project on my to-do list - Would like to build a 22 LR barrel to go on my center fire receiver. What material did you use for your stub? I understand that the factory rim fire barrels were all low carbon steel, similar to 1018.

 

[normks]

Hi Norm - looks pretty good! I have a similar project on my to-do list - Would like to build a 22 LR barrel to go on my center fire receiver. What material did you use for your stub? I understand that the factory rim fire barrels were all low carbon steel, similar to 1018.

hey SEC-22 iv been using 4140 I am sure 1018 would work may be easier to weld also

 

[Rick Leslie]

This is a really cool way to bring back an old single shotty or add some versatility to an existing shooter. I think the factory combos use the offset rimfire barrel as well so there's only one firing pin to deal with. I've got a single waiting for similar treatment as I'm sure many tinkerers do.

A few questions: Did you have to modify the shotgun firing pin? Do you have any indication of FP peening the edge of the rimfire chamber? I've seen the contact area counterbored on factory barrels to avoid or lessen the peening.

I am just a little leery of welding on a barrel stub though. I did it on my TC Contender rimfire barrel but I avoid it on higher pressure rounds where the breech thrust is greater. I know factories braze/weld all the time but theirs is in a much better controlled environment than I can secure.

This is not a critique of your work in any way. You've done a great job on this and I'm sure it will serve you for many years to come. This is merely my observations on the process in general and some easy alternatives. No toes were harmed in these comments (I hope).

The alternative I found was to make a separate breech block from solid stock and drill/thread the ID. Then you can thread the barrel with no worries of heat damage. There is a commercial source for these for the TC Contender and Encore and the block is easy enough to do with simple hand tools. The barrel threading will of course require a lathe unless you get a blank that can be threaded as is.

Again, this is a great conversion and please don't take my ramblings as criticism.

 

[normks]

thanks rick I did have firing pin contact as can be seen on barrel stub on the upper edge have adjusted that wouldn't fire at first. the rim on the case is thicker then the firing pin extension so dry fire wont be a issue . I know welding is critical part and for the most part it is a low pressure case . and I didn't modify the firing pin at all just a blunt rounded pin

 

[Rick Leslie]

So how does it do at the range or in the field? I would really like to see more of this.

 

[normks]

So how does it do at the range or in the field? I would really like to see more of this.

sorry rick fresh off the lathe no polish or crown cut yet did test fire it went bang every time we will know in a week or two. and it also a good practice piece working off center hoping to build a martini rimfire change barrel gun. have the action and it was a 22 mag orig. so why not a 17 hmr and a super mag

 

[Rick Leslie]

I look forward to more progress. Thanks for the build info.

 

[normks]

I have scope blocks and a 6x18 scope on the barrel now hope to shoot it tomorrow if it does good at 100 yards will go 200

 

[normks]

after a cold windy day at the range the 17wsm was under a haft inch at 50 yards about 5/8 at 100 has no forend still never tested the 25 grain ammo either will get the gun finished up next couple weeks