my uncle's .22

[cherian.k.k]

hello
my uncle has prob with his .22 remington rifle.the rifling of the gun has been damaged as some insect had put some mud like stuff inside the barrel and he tried to clean ,i am not sure how he did it[only end part has been damaged ]please advice to what can be done
cherian.k.k

[Mack The Knife]

hello
my uncle has prob with his .22 remington rifle.the rifling of the gun has been damaged as some insect had put some mud like stuff inside the barrel and he tried to clean ,i am not sure how he did it[only end part has been damaged ]please advice to what can be done
cherian.k.k

Sounds like wasps.

You will have to cut the barrel and get the muzzle recrowned.

P.S.: By 'end part', do you mean just the crown or part of the rifling as well?

[cherian.k.k]

thank you for the reply.crown and some rifling is damaged. if barrel is cut will it affact the accuracy,will the gun shop people be able to do it
cherian.k.k

[Mack The Knife]

if barrel is cut will it affact the accuracy

Most probably not. However, it all depends on how well it is cut and recrowned.

Has your uncle's bodged attempt at cleaning the bore affected the accuracy. I suggest you check this first.

will the gun shop people be able to do it

That would depend on the competence of the gunshop you have in mind. If you don't know of a good gunsmith, you would be better off having the barrel cut and recrowned by a good machinist.

Here's what you need to do:

1) Remove action from stock.
2) If the barrel can be removed from the receiver, well and good. Failing which, remove the bolt, trigger mechanism and sights (if possible).
3) Shove a .22 pellet or bullet (if you have one) into the bore just short of the cutting mark. This will prevent swarf from dirtying the bore.
4) The barrel must be precisely centered in the lathe. This is extremely important.
5) First have the machinist cut the barrel at right angles to the longitudinal axis of the bore. This is critical and you should use a true/right angle to verify that the cut is perpendicular to the longitudinal axis of the bore. If it isn't you must cut again.
6) You are now ready to crown the muzzle. You can choose a target crown that is cut at 11 degrees to the face of the muzzle or any other contour or profile that takes your fancy. You can also leave it flat if you like.
7) During the cut it is almost certain that a burr may be created at the periphery of the bore, so have the machinist cut a very small chamfer at 45 degrees. The chamfer is no more than 0.5 to 0.75 mm in width. Basically you are just ensuring that any tiny burr that may be present is removed.
You now take sanding paper / emery paper and smoothen out both the new face (crown) and the chamfer.
9) Remove the pellet/bullet with a cleaning rod and clean the bore thoroughly.
10) Make sure the new crown is kept oiled till such time as it is blued, etc. or else it will rust.


Chamfering the outer edge of the barrel (again by no more than 0.5 to 0.75 mm) is a good idea as it removes the sharp edge that could cut someone. Use sand paper / emery paper to smoothen the chamfer.

Do not overheat the barrel whilst cutting and crowning. Keep the rotational speed as low as possible.

Mack The Knife

[sangi]

MOST importantly(if Imay use the word), at what exact length should the barrel be chopped off at? How does the twist and rifling get effected- I guess (and know ) it affects at the general ranges which one shoots at. Shorter ranges , no probs, but longer-major probs. .22,at the range we shoot at, guess no major probs; but do analyse, how much damage has occurred, by actually firing;any major problems in the grouping at 50 metres...?

[Mack The Knife]

MOST importantly(if Imay use the word), at what exact length should the barrel be chopped off at?

You are getting into the realm of barrel harmonics.

A barrel vibrates in Simple Harmonic Motion (SHM). Thicker the barrel, the stiffer it is and hence, lesser the vibration. One reason why target rifles have thicker barrels.

To actually determine where the cut should be made you would need an oscilloscope. The oscilloscope will show a sine wave when the barrel vibrates. The barrel should only be cut where the sine wave crosses the longitudinal axis of the bore.

What is equally, if not more, important is that Indian law does not permit one to have a rifled barrel less than 20" - legal exceptions aside.

How does the twist and rifling get effected

At the most his uncle's rifle will have a 1-in-14 twist rate and from what Cherian says the cut will probably be made just an inch or two from the muzzle. Assuming it to be 24" barrel, he has nothing to worry about. The only thing he would loose is the choke - assuming there was one in the first place. Also, if he is using open sights, then he would need to get the front sight fixed again. I don't see how cutting the barrel will affect the rifling. So long as any burrs are removed, there should be no problem.

Incidentally, the burn length for a standard velocity .22lr cartridge is 14" or 16", after which the friction within the bore actually causes the bullet to decelerate.

Mack The Knife

[cherian.k.k]

guys i think i will advice him to give away the gun and buy anther as i dout the skill of the local gun shop. Mack The Knife when i told what u have adviced.i got shock of my life, one of his friends had borrowed it from him and it was there it happened and his friend, what should i call him #*^# shot a bullet to remove the block .that's how it got damaged
cherian.k.k

[diskaon]

OUCH....

[mundaire]

one of his friends had borrowed it from him and it was there it happened and his friend, what should i call him #*^# shot a bullet to remove the block .that's how it got damaged

GOOD! So now get the ass to pay for the damages!!

Cheers!
Abhijeet

[nm]

The detail in which Mack The Knife explains really impresses me....even the engg. involved....

I am glad to be part of this forum!!

Thanks,
-Nishant

[Grumpy]

Cutting the barrel back is highly unlikely to effect the accuracy and the location of the cut is extremely unlikely to be critical as regards harmonic oscillation.
Should the rifle become inaccurate after the barrel has been shortened the most likely culprit is poor recrowning.
The use of a simple harmonic damper can improve accuracy on many sporting rifles however the more rigid the barrel the less prone they are to harmonic oscillation.............for obvious reasons.
DO NOT remove the barrel without first scribing the barrel and receiver with corresponding location marks to ensure that the barrel is precisely refitted. If a competent gunsmith is not available I would suggest that the barrel is not unscrewed anyway but the stock taken off and the rifled action taken to a good machine shop and the damaged portion removed by grinding off the damaged portion as close as possible to 90 degrees.
Something that hasn`t been mentioned is the possibility of the barrel having bulged because of the moronically stupid method used to clear the obstruction. If it was a centrefire rifle bulging ( or even worse ) would have been almost inevitable but being a .22 lr ( I presume ) your uncle might have been lucky.......I wouldn`t bank on it though. Barrel obstructions cause a very high, very rapid pressure increase during firing with localised bulging a distinct risk.......... If the barrel has bulged at the muzzle the entire length of the bulge will have to be removed as well as the area of damaged rifling. If bulged at the chamber end the barrel will have to be removed from the action, the chamber and bulge cut off, a new chamber cut, and the thread re-cut.........All in addition to cutting off the damaged portion at the muzzle. In real terms it would be easier - and less expensive - to import a replacement barrel.
So cross your fingers.
Frankly, with friends like that, your uncle has no need of enemies........................