Gunsmithing Switch barrel without nut?

[Apnea]

Seems to me you could switch barrels without a nut if you indexed them to the action or recoil lug and installed appropriately?

Started toying with the idea while in traffic today. Obviously it can't be that easy....

What do I not know?

 

[padom]

it is that easy. it's called a shouldered barrel...torque it on and that's it

 

[Gene Poole]

Mill some flats on your barrels for a wrench or crow's foot.

 

[MDM]

Look at the Curtis Custom Vector action. Slap it hand tight and tighten the set screws.

 

[ptm121]

Some custom smiths will save your receiver measurements and make you a barrel without taking the action to fit it. It requires a little more advanced metrology than just running the reamer in until a the go-gauge fits, but it’s not that hard.

Certainly, you can swap barrels until the cows come home once they are fitted to your action. I’ve seen (benchrest) people order their barrels with hex flats at the muzzle for a socket, so they don’t need to use a barrel wrench.

 

[Ledzep]

Might also look at the American Rifle Co. Barloc system. Apply the thread preload with an allen key instead of 30-100ft lb of torque.

 

[Apnea]

This is really cool, appreciate the info. Got to look a few of these things up and read more....

 

[XLR308]

Kelblys can thread and chamber you a barrel for one of their actions without you sending the action. Have as many barrels in different calibers that match your bolt face as you want. Not sure yet if most gunsmith will do the same though for one of their actions.

 

[DAVETOOLEY]

Easy peezy
Been doing it for 4 decades.
If you can change a light bulb you can change barrels.
I did about 5000 Ai barrels and they all shoulder up.
Add in another 2000 for other brands and you have a good sample size.

 

[Wannashootit]

Haven't done it yet, but see no reason why an oversize recoil lug couldn't be drilled and tapped for a grub screw to the barrel shank. Loosen with a hex key, spin off the barrel. Index marks where you can see 'em, wouldn't even need to remove the action from the stock. Why not?

 

[ptm121]

That wouldn’t put any tension on the threads. You need a solid lockup or your headspace will change and the barrel will shift under recoil.

 

[Wannashootit]

^^
Omitted that I would do it with a pinned lug...
With a tight, interference fit, I'm not confident there'd be an issue- but I get your point.

 

[ptm121]

Even if you pin the lug and have the barrel wring-fit with the lug... it’s going to move around without the threads being torqued down.

 

[Ledzep]

Yeah hand-tight barrels are hit or miss on if they'll shoot good (consistently) or not. 20-30 ft*lb of torque or more eliminates the worry. I know there are BR shooters and others that run hand-tight with success, but I've also seen rifles that shot like dog shit only to find the barrel was barely torqued on. Torquing to 50-100ft*lb fixed it.

It's important to realize, also, that a torque spec is a back-solved spec for thread preload. That's why torque specs change with lube, because it changes the friction coefficient between the male/female threads (one of the factors in the equation for converting thread load to torque).

I think that's the main difference between the WTO Switchlug and the ARC Barloc. One is screwed on hand tight then clamped in place (switchlug). With the Barloc, tightening the "clamp" screw pushes circumferencial wedges forward and backward between the barrel and action face (or recoil lug) that develop preload that IIRC is roughly equivalent to 100+ft*lb of torque.

The set-screw idea is similar in theory to the Switchlug, but in addition to having no thread preload (well, minimal, whatever comes from you screwing it on hand-tight), creates a bias in the direction of the set-screw, whereas the switchlug is more or less concentric.

 

[MDM]

Haven't done it yet, but see no reason why an oversize recoil lug couldn't be drilled and tapped for a grub screw to the barrel shank. Loosen with a hex key, spin off the barrel. Index marks where you can see 'em, wouldn't even need to remove the action from the stock. Why not?

This is similar to what the Curtis Vector does, but with integral lug and it works. Last weekend's LRSE Prs match was won using a hand tight barrel and the set screws on the Vector securing the barrel. Not sure that it would work the same with a standard/non-integral lug.

 

[hereinaz]

Seems like a shouldered barrel, with the WTO switchlug, pinned, or the Barloc would be the way to go if you want to load the threads more than handtight. I have run Savage barrels, and its not as fast, but changing a barrel isn't that hard. Man, taking off a factory barrel is another thing...

 

[duramaxed]

I bought into the barloc idea, but I think the Vector and WTO Switchlug have proven so far that handtight barrels are shooting just fine. They have multiple people changing barrels with little zero change. Had Bighorn released a LA Origin at the same time I would've went that route with a Switchlug rather than the barloc.

 

[hereinaz]

I bought into the barloc idea, but I think the Vector and WTO Switchlug have proven so far that handtight barrels are shooting just fine. They have multiple people changing barrels with little zero change. Had Bighorn released a LA Origin at the same time I would've went that route with a Switchlug rather than the barloc.

I'd think you gotta be diligent watching the handtight barrels. I don't want that concern...

 

[hereinaz]

Was remembering that Savage shooters set headspace with the barrel nut, and red-loctite the nut in place to act like a permanent shoulder. Then, spin it on an off without having to adjust headspace again. With a Savage pre-fit barrel, this makes it so you can do all the work.

 

[kthomas]

I'd think you gotta be diligent watching the handtight barrels. I don't want that concern...

I personally would have a hard time trusting them. It's a single point of failure that can ruin a day of shooting or a weekend match.

Besides, how many people need to swap barrels out so often during a day to make it worth while? It's very easy to swap out a shouldered barrel, you just need a barrel vice, action wrench and torque wrench.

Right now the switch barrel thing seems like a trend. I'm curious to see if this trend sticks around, or if it mostly dies as people analyze the risk vs reward benefit.

I myself am going to stick with shouldered barrels. My gunsmith has my action specs, so I can get a shouldered barrel made up at anytime without my gunsmith seeing my action. Not to mention it's incredibly easy to swap out a shouldered barrel if you have the right tools.

 

[Gene Poole]

I always use two pins for the lug.

 

[Travis T]

This is good info as I have been considering getting an MPA switch lug rifle. I was planning on having a rifle built by local gunsmith using a Curtis Axiom action anyway, so thought this was an interesting setup when I found out about it. I look at it as also getting a .223 barrel and bolt for cheaper training and keeping some use off of the main caliber barrel. Also I would use it for shooting the club matches that are .308/.223 only. Would be great to use your same gun and scope. Just seems really convenient if it works as advertised.
As far as having to diligently having to watch the setup, wouldn’t you just have an index line to glance at to verify any movement of the barrel? I guess I don’t see the hassle of it but I may be missing something.

 

[flyer]

I ordered the $50 Barloc special with my Nucleus but not specifically to create a switch barrel setup.

I figured it would be an easy way to barrel my receiver without a barrel vise or action wrench.

I did buy a Savage take-off .308 barrel so I have something to switch to but that's more in preparation for the day I leave California, become a free man and buy a can.

I don't think I'll be switching barrels much at all unless I decide I need to shoot up a bunch of South African 7.62*51 surplus in a nice rifle with all of the toys...

Oh, another thing, I think the Barloc is by far the best system. You don't have to worry about hand tight, you don't have to pin the recoil lug, you can change the headspace if your bolt changes for some reason and it's the only system that gives you good barrel thread preload.

 

[W54/XM-388]

The Accuracy International setup which has been around for a couple decades is pretty much just that.
Barrels are made to exact standards, simply screw one in by hand and then apply the torque wrench to put the correct torque on and all done.

You'll need a vice and the barrel change kit for the ones made before 2014, but once you have that kit, it takes probably 20 minutes or less to change out.

The post 2014 versions just require a little torque driver.

 

[hereinaz]

I ordered the $50 Barloc special with my Nucleus but not specifically to create a switch barrel setup.

I figured it would be an easy way to barrel my receiver without a barrel vise or action wrench.

I did buy a Savage take-off .308 barrel so I have something to switch to but that's more in preparation for the day I leave California, become a free man and buy a can.

I don't think I'll be switching barrels much at all unless I decide I need to shoot up a bunch of South African 7.62*51 surplus in a nice rifle with all of the toys...

Oh, another thing, I think the Barloc is by far the best system. You don't have to worry about hand tight, you don't have to pin the recoil lug, you can change the headspace if your bolt changes for some reason and it's the only system that gives you good barrel thread preload.

Some Savage prefits are not long enough to thread into a Savage action far enough to headspace, because the Barloc requires a little more room than is threaded. I first heard this about a Proof prefit. That person had to use the standard recoil lug instead of the one that comes with the Barloc. I have a Savage Barloc as well, and my Criterion barrels are not threaded enough to allow use with the Barloc on a Savage action. Interestingly, my factory Savage barrels have just enough threads to use the Barloc.

I ordered the Nucleus, and I am hoping that the Barloc will work with the Criterion and other barrels.

If not, I hope that PVA and others figure this out and just give a little more threads on the prefits to use the Barloc. Otherwise, it isn't going to work out as well as hoped for me.

 

[flyer]

If that's the case, I'm going to order up a threading die so I can extend the barrel threads.

 

[Rthur]

As mentioned it's not like building a steinway.
Witness marks simplify re-installation.

R

 

[BlackFenix]

Some Savage prefits are not long enough to thread into a Savage action far enough to headspace, because the Barloc requires a little more room than is threaded. I first heard this about a Proof prefit. That person had to use the standard recoil lug instead of the one that comes with the Barloc. I have a Savage Barloc as well, and my Criterion barrels are not threaded enough to allow use with the Barloc on a Savage action. Interestingly, my factory Savage barrels have just enough threads to use the Barloc.

I ordered the Nucleus, and I am hoping that the Barloc will work with the Criterion and other barrels.

If not, I hope that PVA and others figure this out and just give a little more threads on the prefits to use the Barloc. Otherwise, it isn't going to work out as well as hoped for me.

Do you happen to know about how long the thread have to be for a Savage action? I have a new X-Caliber barrel on the way and would like to use the Barloc