Barrel Chopping

[airgunandy]

I've read a few things on shortening air rifle barrels, but still not quite sure how to do it. I'd like to try it on a couple of rifles. After shooting my Benjamin and Sheridan pumpers, some of my springers seem too long! 

My first victim would be a side lever springer (TF41). What is involved in cutting a barrel?
Can a tubing cutter be used to at least make a square guide line for the hacksaw? Will using a tubing cutter induce a bit of choke?

[rabbitguy]

I have done it with a hacksaw and with a grinder using a cutting disk. either way to go you will have to redo the crown. You should also remove the stock it will make it a bit easier to handle.

[DMikeM]

Man I want to chop my B30 bad but don't want to screw up any chokes that it may have, or should I even worry about that?

[Bentong]

I use a miter box and a hacksaw to chop my barrels. Just go slow so you don't cut the side of the box. Get the imperfections with a flat file then re-crown. Q-tip will snag on bur and polish the crown and q-tip it again until snag free. 

[larspawn]

Just start on a cheapy.

Yes you can do it with a hacksaw or a sawzall but don't expect it to look perfect.  You're better off with a metal blade on a circular saw.  I used to use my radial arm saw with a metal blade but finally sprung for a metal chop saw.

Here's what I do...

First, get a wooden dowel that fits your barrel.  

From the breech push a pellet slowly from the breech towards the muzzle.  Note any points along the barrel that you get more resistance.  

Now decide how long a barrel you want.  Note that you will lose about 10 FPS per inch on a CO2 rifle.  Minimum length I would go is about 14"  This is because CO2 gas is still expanding to this point.  On a springer grab the  barrel at the "choke points" and make sure that you can get enough leverage to comfortably cock the rifle.  On a sidelever the sky's the limit.  Cut point will be determined by choke point or asthetics.

Once you have established your cut point mark it off on the barrel with some tape.

Now place the tip of the dowel on this spot and mark the dowel with a pen/sharpie at the muzzle point.

Insert a wadcutter pellet in the barrel from the muzzle.  Push with the dowel up the the point marked on the rod.  Now push about 1/4" more.  This will form a plug so that metal shavings will not pollute your barrel.  Cleanup will be easier and you won't run the risk of scratching the rifling.

Line up with whatever cutting implement you have and cut the barrel.  Obviously try to keep it square.

Once cut now you can clean up the cut by facing with a file, sanding block, etc.

A nice flat file will also taper the outter edges of the barrel which will inevitably have sharp shards.  Take your time doing this because a taper and a smooth muzzle face will make it look like a pro.

Blow out the shavings from the end and push the pellet out from the breech end.

Get a new wadcutter and seat into the muzzle end just so the skirt is just at the surface.

At this point I would reblue the barrel end.  This will inhibit rust (well actually it is rust) and make it look like a pro.  Do not get blueing in the barrel.  If you have seated the pellet skirt right at the surface this will help.

Now seat the pellet just below the surface of the newly cut face.  Re-crown the barrel.  I like to create a slurry of compound in the barrel end.  I run the screw in my compound and wet the resevoir (spit works good!)  I use the brass wood screw method.

Push the pellet out and clean the barrel.  I like to do a JB Bore paste clean at this point followed by several patches with Goo Gone.  You'd be amazed that it will already be clean and a few patches is all that is required.

Yeah you can do the q-tip test but if you did the above steps correctly you will be fine.  I'd rather inspect using a magnifying glass or naked eye.

Congratulations you've chopped your first barrel!

[airgunandy]

Thanks for the info guys!

[larspawn]

"Now seat the pellet just below the surface of the newly cut face.  Re-crown the barrel.  I like to create a slurry of compound in the barrel end.  I run the screw in my compound and wet the resevoir (spit works good!)  I use the brass wood screw method."

I guess I assumed you would know the crowning technique using a #8 or #6 brass slotted round head wood screw chucked in a drill.  Using appropriate compound you can polish a crown very well.  Use the search function because I know there has to be something on crowning in the archive.

Andy

[bart the fart]

chopping a barrel made clear!!!! thanks andy...i might just try this now, based on your "clear cut" advice...all puns intended cheers the fart

[howie1a]

Hi to start with most rifles do not have chokes that said , I have chopped quit a few barrels , I find a hack saw just fine after cutting off the barrel just use either your bench grinder or if you have a disk grinder square up the end then polish it using fine paper and if you have it a rag wheel with polishing compound, next you can re crown it , one way is to take a ball bearing or a round head screw and grinding compound and form the crown. I just use my dremal with a round stone much eayser and faster then a piece of fine paper formed into a cone and deburr the inside of the crown, now I try the rifle to see if it shoots good if not I redo the crown till I get it to my liking , the final thing is to using cold blue touch up your work, Now I do have a tool to put a choke in the rifle if I feel it is needed. PS "John of Pa. the tuner " also has a set of choke blocks and he can do a fine job of chopping a barrel if you want. Howie