barrel shank conversion - possible?

[kevwil]

Is it possible to convert a large shank barrel to standard shank size? How radical of a change would it be? A simple re-thread, or something more extreme like chop the existing shank off which would require re-chambering?

[lrshooting]

Is it possible to convert a large shank barrel to standard shank size? How radical of a change would it be? A simple re-thread, or something more extreme like chop the existing shank off which would require re-chambering?

Im pretty sure you aren't going to be doing a simple rethread.

Small shank=1.055
Large Shank=1.120
Difference is .065 (65 thousands)

You would probably either strip or bind your threads. Maybe somebody else has tried it?

Two questions.

-Why do you want to change it? There are lots of options available for large shank and its really more suited for the larger chamberings anyway.

-Dont you think it would be cheaper and more reasonable to just get another action? The cost to actually convert a large to small would be expensive even if all you had to do ream and rethread. Itd make more since to put that money towards another action and then you would have two guns to play with instead of one.

If the action is already messed up, and it is really such that you cant convert it, the cost to bore out the reciever over sized, install a bushing and rethread to small shank is going to be pretty expensive. Probably cheaper get another action unless you have the tools.

[Robinhood]

Yes it can be done. The barrel will look better if you turn the whole barrel down to a major od of 1.055. if it is a bull barrel. Keep it concentric. Then, as best as you can pick up what is left of the old threads and cut to 1 1/16 20 TPI dimensions. Keep the threads close to the action dimensions so it is not a sloppy fit. Or you can turn it chop it and re-thread and chamber it.

[kevwil]

Two questions.

-Why do you want to change it? There are lots of options available for large shank and its really more suited for the larger chamberings anyway.

-Dont you think it would be cheaper and more reasonable to just get another action? The cost to actually convert a large to small would be expensive even if all you had to do ream and rethread. Itd make more since to put that money towards another action and then you would have two guns to play with instead of one.

This is from an abandoned F-class project, a 30" bull barrel in 6x47 Lapua. I've been trying to sell the barrel for over half a year, with no luck, so now I'm wondering if there's any way to put this fancy paper weight to use.

I don't think it's reasonable to "just get another action". Or at least my wallet doesn't think so. It would also need some custom dies, some brass, a stock, a scope mount, and a scope - that's $2-4k depending on which scope you choose. If I could afford all that, I would not have abandoned the project to begin with.

Long story short, just trying to find a way to get some use from this barrel, for next to nothing.

[geargrinder]

Yes, just a simple re-thread. There's more than enough to clean off the old threads and turn new ones.

[wbm]

Have had two done....not difficult at all. A qualified gunsmith can do it in less than an hour.

[short round]

Keep in mind the cost of having this done correctly, needs to be set up & dialed in, on lathe, turned & threaded. Cost of work & shipping or travel expense, your still going to need dies & brass. Find out what it will cost.

[red caddy 51]

What Geargrinder and WBM said.
I have fit all manner of used/take off barrels to various Savage actions. It is standard practice for me to cut the chamber end of the barrel so that the remaining chamber is smaller/shorter than the new one and square to the bore, Usually, I will pre bore and thread a short (2.5") piece of barrel stock, (match the barrel material) then, turn and thread the chamber end to a large, coarse thread (often 3/4-16) I cut the threads to 75% or more, thread engagement. When the fit is right, I clean everything and assemble with Devcon or Belzonia metal filled Epoxy.

After several days to cure the epoxy, I turn the sleeve concentric with the bore, turn to size and thread to fit the action. (I really like tight thread engagement)

When reaming the new chamber, I will go .035-.045" deeper than I need too, get as near perfect a chamber as I can, then face the barrel to the desired .030-.035" stick out of the "go" gage. That's the easy way to get the headspace precise.

This is a fair amount of machine time and in a small job shop, might cost as much as $200-250. (I've found that most line machinists don't speak GUN and may not appreciate the skill level and time required to attain the desired concentricity) Any gunsmith, worthy of the name, should be capable of the required accuracy. Price will be determined by time/machinery available, time of year and how full the "waiting job" rack is.

I don't have much time available to do this kind of work anymore, but I manage to do a couple a year, just for me...

Paul

[sharpshooter]

^^^^^^bad idea....

[red caddy 51]

Sharpshooter,
Specifically NOT wanting to stir the pot, pee in your pool or cast aspersions, would you share your reasoned objections to my sleeve and re thread methodology?

Thanks, paul

[sharpshooter]

First of all, the method you describe is totally unnessesary for the OP's situation. A simple turn and rethread will suffice.
Turning the shank down to a small diameter and then adding a sleeve compromizes the strength of the chamber. No matter how tight the threads are on the sleeve and the fact that a filler/adhesive has been added, the chamber will expand more than if it was a solid diameter. I know this because I have also done it as an experiment. After numerous jolts of high pressure and rapid heat dissapation, the Devcon starts to deteriorate to the point there is no solid joint anymore. The chamber slowly grows in diameter under pressure and contracts at a greater rate than the cartridge brass does to the point where extraction is very difficult even with moderate loads.

Gene Beggs ran an experiment using a sleeve with 2 different rate thread pitches to index a barrel with out affecting headspace. His sleeves were much thinner and left more meat on the barrel shank. His tests ran into the same problem. The barrel indexing theory was proven, but the problem lied in the fact that the extra joint allowed for more case expansion.

If it works for you, fine, but there are no reputable gunsmiths that would give this a nod for an acceptable practice.

[Robinhood]

I am in agreement with Fred. I cut on metal daily, not a gunsmith though, however if you have ever turned, repaired or threaded you would know that the "sleeving" idea is not an option here. For one, why would you want to take a simple turn and re-thread and make it a hack job? read post #3.

[red caddy 51]

Thanks for the input gentlemen. Obviously, all my post did was "muddy the waters" of the question the OP asked. Sorry about that.

Paul

[wbm]

A simple turn and rethread will suffice.

Listen to what he is saying. He knows what he is talking about. Course if you are the kind of person that want's to touch your nose with your finger, other than the most direct way, what he is saying will probably not be acceptable.

[bsekf]

I looked at your ad and considered turning and threading. I wanted to cut the barrel to a usable length, too. Decided I might better buy a new barrel. I do have a 22-250 AI that started life as a large shank bull and was turned and threaded to small shank. Factory Savage and is a better shooter than my custom barrels. Go figure.

Bill