Any folks out there threading a shotgun barrel?

[jpender]

Hi all, I'm a real novice on the shotgun side of the house, so any input is welcome. I'm working on a basement cheap backpack gun build for squirrels and other small game. I picked up a single shot 20 gauge a while ago, and had the barrel cut down to 18". I'm going to do some woodwork on the stock to get her to fold nearly completely in half, but I'd like to be able to use a screw-in choke. Is there anyone that could cut threads on the inside of the barrel to accomodate a choke in middle/North Georgia?

Thanks in advance for your help,
J

 

[spencer60]

Got to be careful on this... a lot of older guns may not have the wall thickness needed to remove material for a choke. You definitely want a gunsmith who knows what's safe or not.

 

[GAgunLAWbooklet]

I think the cost is prohibitive, around $100 for the threading to use choke tubes.
I wouldn't do that to a cheap knockabout utility shotgun.

But, you might consider a youth model shotgun with a 21" or 22" barrel factory-threaded to use choke tube sets.

I just bought one such gun, a Chinese-made Stevens / Savage 320 in 20 ga, for only $150. At WalMart.

And the barrel is easy to take off if I wanted to stick it in a backpack to walk into town discreetly with only a few inches of the barrel protruding from the top of a small backpack.

When you're walking around the woods, gun assembled and ready for use, a 22 inch barrel is not too long. Especially on established trails.

 

[jpender]

Got to be careful on this... a lot of older guns may not have the wall thickness needed to remove material for a choke. You definitely want a gunsmith who knows what's safe or not.

Definitely looking for a professional to do the job. It's a cheap Hatfield, made in the last year. My digital caliper measures the barrel thickness at 2.15mm, do you have an idea about if that's sufficiently thick or not?

 

[GAgunLAWbooklet]

You may want to pattern your now-unchoked cylinder bore 20 gauge with several different loads. You might get a tight enough pattern "as is" if you find a particular load that your gun likes best.

I once bobbed a shotgun barrel to 12" and still had it throwing 9-pellet 00 buckshot at a spread of 2" per each 3 yards of distance.
That was NOT Federal flite-control either. Just plain old-fashioned buckshot.

 

[jpender]

You may want to pattern your now-unchoked cylinder bore 20 gauge with several different loads. You might get a tight enough pattern "as is" if you find a particular load that your gun likes best.

I once bobbed a shotgun barrel to 12" and still had it throwing 9-pellet 00 buckshot at a spread of 2" per each 3 yards of distance.
That was NOT Federal flite-control either. Just plain old-fashioned buckshot.

That's a good point, I'll have to try that out too.

 

[GAgunLAWbooklet]

A cylinder bore 20 gauge shotgun barrel should have an inside diameter of .667 inches.

What does your Hatfield barrel measure at the cut-off point?
Both inside and outside diameters?

 

[jpender]

A cylinder bore 20 gauge shotgun barrel should have an inside diameter of .667 inches.

What does your Hatfield barrel measure at the cut-off point?
Both inside and outside diameters?

ID: 0.621 inches
OD: 0.775 inches

By my reconing, measuring freehand.

 

[GAgunLAWbooklet]

Quote from a shotgun gunsmith's website:

"Minimum OD at the muzzle for 20 ga. Standard Diameter Truchoke installation: .705"


Maximum ID of the bore for 20 ga. Standard Diameter Truchoke installation: .625"


If those values given above happened to exist on the barrel in question, the difference in diameter would be 0.08. That's 8/100 of an inch, or 2.03 mm.

And that's the DIFFERENCE across BOTH sides of the circle. So if you're going to measure only one side of that circle --the thickness of the wall at only one point-- it would have to be more than half of that 2.03 millimeter measurement. Basically more than 1 mm.


It sounds like you have enough metal to work with.

 

[jpender]

Quote from a shotgun gunsmith's website:

"Minimum OD at the muzzle for 20 ga. Standard Diameter Truchoke installation: .705"


Maximum ID of the bore for 20 ga. Standard Diameter Truchoke installation: .625"


If those values given above happened to exist on the barrel in question, the difference in diameter would be 0.08. That's 8/100 of an inch, or 2.03 mm.
It sounds like you have enough metal to work with.

Fantastic, thank you for your help. I'll take this up with a professional gunsmith to get their throughts on if they can pull of the job. Thanks again!