choking a rifle barrel. anybody know how to do this?
Have my p12 on the way as is and at and if anything else push come to shove the barrel needs to be choked down how would one go about it?
i have access to a lathe and a pip threader for threading hardline piping, i hear that replacing the cutting heads with roller bearings from somebody like timken and using the machine to spin the barrel as you increase the pressure. i would only need to choke the end say 1/2″ maybe 3/4″?
what would you say is the optimal choke length for a rifle barrel and how would you go about doing so?
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KM, I have heard of other air gun gurus doing the same thing to see if it help a funky barrel… 😉
If that is all you need, .001″ try this old machinist trick. Heat the end of the barrel to dull red. (APX 1200 deg.) this won’t be high enough to cause scaling, but when you dunk it into the quench, Muzzle only, . (Transmission oil works well), there will be a very slight shrinkage. Re-crown, and polish the interior or the bore with something like flitz on a tight fitting patch.
You are now choked! 😉
We’ll call it the Heat Shrink technique! :rofl:
Knife
With Modern machines you can dail in the pressure, start slow, and find the right pressure,
and take a box of pellets with you, and a rod, to try after some pressing.
They did it for me with a nice choke on a straight bore barrel.
Tell him before, you pay his time 😉
nice tip…. i know such a guy, actually a few. never dawned on me that they could choke it down a little. if need be just .001 is enough.
thanks woodie
A guy who work with hydraulics for high pressure hoses and fittings can do it for you.
With Modern machines you can dail in the pressure, start slow, and find the right pressure,
and take a box of pellets with you, and a rod, to try after some pressing.
They did it for me with a nice choke on a straight bore barrel.
Tell him before, you pay his time 😉
well see. the barrel rusted really bad to the point that a single pump on the gun would get the pellet stuck. i would have to ram it out with a rod. i cut the end off that was rusted and it shoots now but not nearly as well as it should be. the guns trashed as i said, stocks broken and the side plates are all cracked from time and neglect.
its a tinker rifle that im using to learn machining for rifle stuff and learning to properly choke a barrel is essential to my learning curve and knowledge.
im almost thinking of using my lathe and my 4 jaw chuck, clamping the barrel in a ring lock on the deck and putting bearing in the jaws and turn it by hand with a strap wrench and increase the pressure slowly while turning and see if it works out
People get great results on these rifles with no choke. Some of the real long range guys run none. The choke for the most part just gain you a few fps. However these rifles are easy to go to much speed out of. So bit redundant unless your after pushing Max shot count. I would say if its your only barrel just try it with no choke. It should work very well with out it.
roland, i read the same forum post which is why i mentioned the pipe threader with the cutting heads replaced with bearings.
i know since ive never done it before i would need to try it then check it after each incrimental step i took. i dont want to go too far, and since this barrel is trash already i highly doubt i can hurt it. this isnt for the p12, its for a old crosman pumpmaster that the barrel rusted on, when i cut it i noticed the there are signs of a choke. the guns trash, will be a good trial and error period i guess for it
Choking the barrel it not the problem….
Choking it so that it actually improves the barrel is the issue.
You must have experience in actually “improving the barrel” to be successful.
If you do it to much you have to cut off the choke and start all over again….rinse and repeat.
Yup! Seen it somewhere getting the job done with a knurling type tool on the lathe. Smooth rollers though!
Don’t see it being difficult once you give a couple of tries on a plain pipe/discarded barrel.
Pomona air guns use to list barrel choking but I’m not sure if it was only one size. I don’t see it anymore. I know Jim Gaska is choking the 22 barrels he sells also.
I think that I once saw a posting on another airgun forum’s machining section Iin which they were using a standard plumbing tubing cutter to just score a single line at the last inch of the barrel.
I wonder if a variation of knurling type tooling might be appropriate on the lathe?
Ive been thinking about chocking a barrel by making the end connical over say 20mm bij 5 degrees.
make a sleeve with the same angle. Do the math on what shrinkage you need and heat the bushing.
than put it over your barrel end tightly. Let cool and you should have a nice and gradual choke.
ive been running machines and lathes since i was 14. i have the tools i just dont have the knowledge because ive never needed to make a pipe smaller. i know how to expand a barrel end to relieve it but i dont know how to choke it
You must be experienced to choke a barrel successfully.
It is a fools errand for a hobbyist to do it on the only barrel they have for a rifle.
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I have barrels that have been cut down from the muzzle and rechoked by the old Theoben. They used to do it with a collet type hydraulic press with a smooth bore, basically squeezed/compressed the last inch. I believe done cold. Smooth twist barrels, I understand, are done same way but with a twist profile to the collet bore as opposed to smooth.
Don’t quote me :whistle: