clamping muzzle

R

robbor

Guest
So a tight muzzle rimfire is supposed to shoot better and I recall that moderate force can affect a bore. Im thinking about trying to put a short flat spot at the muzzle and then use a clamping collar to constrict it. This would roughly be a sporter/Medium contour. Anybody heard of clamping the muzzle?
 
The trick would be getting the constriction perfectly even so the bore is perfectly round. I had one like that many years ago that shot really well. I had the tuner really clamped. Would it have shot well without the clamping, I don't know because I didn't realize the tight tuner had such an effect until after the barrel had gave out. Rich
 
Shrinking on a ring?

How about shrinking a ring on? (i.e. heat the ring enough to expand over the muzzle, then when it cools it will return to size).

SteveM.
 
Hi Robbor,

If you are shooting your sporter in IR 50/50 three gun you might consider the rule...

"Minimum length from the trigger to the end of stock, excluding butt pad, must be 12.5". No vibration devices allowed. Barrel must be made out of one piece of metal with no attachments except for the action and a nut to secure the barrel to the action".

I'm not trying to discourage your experimenting, just so you are aware of the rule. :)

Al
 
good ideas

The shrinking ring is a good idea. I was thinking of a collet type but the ring would be much simpler. I dont shoot competition, just like to tinker and try to do thing the right way.
 
Before you wast your time, I don't think you can shrink a "ring" on a barrel by heating it, wont the inside of the ring get smaller as you heat it.
SS
 
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Many years ago I watched a guy heat a roller bearing to red heat to get it to fit on a differential pinion. I wouldn't want to guess what that did to the bearing, but it did slip onto the pinion easily, which it did not do when it was cold.
 
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I could be wrong, give it a try and let us know how it goes.
SS
 
The ring gets bigger.

The ring will get bigger bigger on the OD and bigger in the ID when it is heated. I am 100% sure.

Steve
 
I thought for sure it would expand the same in all directions, and if that's correct it would get bigger on the outside and smaller on the inside, maybe ?.
SS
 
Single Shot said:
I thought for sure it would expand the same in all directions, and if that's correct it would get bigger on the outside and smaller on the inside, maybe ?.
SS
Click to expand...
Man, ain't you seen them heating a steel tyre to fit back onto a wagon wheel in those western movies? The Duke would hang his head! :rolleyes:
 
Vic Swindlehurst did this to a center fire barrel many years ago I believe. I remember Al Mirdoch describing this idea to me in the late 80's -it worked to choke a inconsistent barrel and improved the groups .

Glenn:D
 
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Single Shot said:
Before you wast your time, you can not shrink a "ring" on a barrel by heating it, the inside of the ring will get smaller as you heat it, not larger.
SS
Click to expand...
Only until it reaches a steady state temperature. And even then only if it's heated from the inside diameter. Once a uniform temperature is reached the ID will indeed be larger than it was. It's a common practice in mounting bearings and all sorts of other items on cylindrical shafts. The metal does get larger in "all directions:" as you said, but that includes circumference - which on an "inches per inch" basis gets larger much faster than the diameter.
 
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Heat

It was funny to watch the electricians heat a bearing in the oven and then try to carry it from the mess deck to the engine room in a submarine and install it on a generator shaft before it cooled too much. It often took several tries but they eventually would succeed.:)
 
thanks

Thanks for the replies everyone. Lots of good information.
Here is a link to heat shrink rings, I believe they are nickle titanium or something. I thought Mcmaster used to carry them but could not find them.
Ill keep my eyes open for them on ebay:p.
http://www.intrinsicdevices.com/
 
Nothing fancy.

You don't need one of those fancy bi-metallic shape memory alloys to make a heat shrink ring. You can just whittle it out of plain old steel.

SteveM.
 
ok

Ill look up the thermal expansion of ss, that would be alot cheaper and easier.
 
robbor said:
Ill look up the thermal expansion of ss, that would be alot cheaper and easier.
Click to expand...

While you are in the "looking it up" phase
http://ringfeder.thomasnet.com/category/yless-shaft-hub-connections-external-shrink-discs-?
http://www.climaxmetal.com/kla733.htm
also check the "other references" of the following link for "Shrink disc"
http://www.patentstorm.us/patents/5902066/description.html

These types of clamps can put a permanent reduction onto a solid shaft that remains smaller even after the clamp is removed. We once reduced the diameter of a 4" shaft by 0.015" by over torquing one by accident. So I know they can do it, and if one is carefull in the order the clamping bolts are tightened, reasonable concentricity should be able to be maintained. And so long as you don't go crazy and go beyond the yeild point of the barrel you can possibly even tune the concentricity.
 
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