Krauger action wto switchlug build - 3 caliber ackley improved need advice. 510 whisper 338 lapua 300 rum.

[Archimedes]

Hey, so I’m putting together a rifle
Krauger vpr sst 338 long action receiver nitrided
3 barrels from McGowan precision
1 338 lapua 40 degree ackley improved 32 inch bull
1 300 rum ackley improved 32 inch bull, possibly extended cut chamber for 3.740 coal loads
1 510 whisper 10 bull
Xlr atom chassis, built as a pistol but can be converted to rifle. Pistol config is for the 510 whisper using a brace.
3.850 CIP magazines
West Texas ordnance switchlug system

Couple of questions
Can I modify the chassis to accept the switch lug system and where can I get it done in quality manner that’s not pricey.
Will wto take in McGowan barrels to do this build?
How likely am I to experience feeding issues with all 3 calibers?
Trigger recommendation?
Can I buy an extra bolt for the 300 rum from Krauger or perhaps some other company and how much will that run me?

Any recommendations overall on the feasibility of this build? Different parts recommendations or reputable gunsmiths? Am I missing anything here?
I’m selling my Remington sendero ii 300 rum to partially fund this, I figure the cheapest way for me to shoot all 3 calibers and do it easily is to go this route with the switchlug.
Main concerns are budgetary in nature.
Main point is to have a rifle system capable of shooting all 3 calibers accurately and to switch between the calibers easily, ergo switchlug.
Mandatory to be able to build it as a pistol first so I can have a 10 inch barrel and use a brace while also being able to use a rifle stock with the rifle barrels.

 

[TheBigCountry]

sounds like too much work gong from pistol to rifle then back again

Build a separate rifle and a separate pistol and SBR the pistol

 

[DairyDictator]

I'd be willing to bet that by trying to do all of this with one rifle system, you're going to run into a significant amount of problems. Shootability, feeding problems, generalized frustration of all the work required to switch everything over to a new caliber, and a significant amount of wasted ammo zeroing the rifle every time you switch things over. Given the fact that these aren't common or cheap cartridges to buy ammo or components for, that last one is going to suck.

Coming from a guy who went down this road in a couple different cases. the quick swap shit ain't all it's cracked up to be. By the time you buy all the necessary components and deal with all the shortcomings from compromises made in the name of universality, you're time and money ahead outfitting multiple rifles for different use cases. It's really easy to make enough compromises that the rifle isn't really good at anything anymore.

At a minimum, I would build the .510 whisper into it's own rig and maybe talk to Kauger and WTO about the other two, but I would still consider just building the 338 and keeping the sendero for 300 RUM assuming you like the rifle.

 

[Mike Casselton]

The Kauger action has a hood over the top and side of the recoil lug.
Did you have yours machined off?

If not, the WTO lug won't work

 

[Mike Casselton]

In reference to your extra bolt question, you can buy extra bolt heads. No need for an extra complete bolt assembly.

 

[Archimedes]

I'd be willing to bet that by trying to do all of this with one rifle system, you're going to run into a significant amount of problems. Shootability, feeding problems, generalized frustration of all the work required to switch everything over to a new caliber, and a significant amount of wasted ammo zeroing the rifle every time you switch things over. Given the fact that these aren't common or cheap cartridges to buy ammo or components for, that last one is going to suck.

Coming from a guy who went down this road in a couple different cases. the quick swap shit ain't all it's cracked up to be. By the time you buy all the necessary components and deal with all the shortcomings from compromises made in the name of universality, you're time and money ahead outfitting multiple rifles for different use cases. It's really easy to make enough compromises that the rifle isn't really good at anything anymore.

At a minimum, I would build the .510 whisper into it's own rig and maybe talk to Kauger and WTO about the other two, but I would still consider just building the 338 and keeping the sendero for 300 RUM assuming you like the rifle.

According to wto the moa shit you’d experience is .5 and I would mostly be shooting 338 lapua or 300 rum. I feel like it’s such a minimal poa shift that I can re zero fairly easily, I do reload my own ammo as well so it’s not as pricey as factory ammo.

Also this way I’m able to retain my 300 rum, if I can sell the sendero, so it’s just another cost saving measure. Plus I do want a thicker longer barrel with a different chamber.

If I were to keep the sendero and use a pacific tool and gauge receiver for the 510 and 338 I could have the expense be mostly the same, you’re right. I just wouldn’t get an improved chamber for the 300 rum, would still be fairly more expensive when factoring in not selling the sendero.
Also apparently rem 700 receivers can’t handle the lapua? So that might not be the best option although I’m not sure if that’s just fuddlore because they were built to handle 338 rum which is arguably more harsh, besides perhaps a slightly increased bolt thrust with the .044 inch difference in case head diameter.

 

[Archimedes]

The Kauger action has a hood over the top and side of the recoil lug.
Did you have yours machined off?

If not, the WTO lug won't work

They gave the suggestion of the krauger, so I assume it will work and that they will modify the receiver in someway.
My main concern is modifying the chassis.

 

[JR1200W3]

Why do you think the WTO Switch-lug is necessary in this situation? Why not just screw the barrel on/off with torque?

The industry went through a whole switch barrel gadget craze about 5 years ago and people found out that big zero shifts occured when the barrels took unintended bumps. The way the Switch lug and BARLOC clamped the barrel is albeit similar to an AI but in practice didn't seem to execute the idea in the same way. Maybe because it's a separate piece that doesn't have the barrel torque keeping it planted. Same for the Terminus style grub screw. The action face on those isn't floating with minimal clamping torque from the barrel shank. It's the action itself. And even AI owners found that a higher clamping bolt torque or even a bit of barrel torque (above and beyond what AI instructions state) improved the return to zero and rigidity of a mounted barrel.

Obviously you're going to do what you want, but imo the WTO SL is extra expense, makes those three barrels proprietary, and requires forever future barrels intended for that action limited. And it does a worse job than just screwing the barrel on with some torque. The way that joint was designed.

Clayton is an absolutely awesome dude. Just my opinion on a technical discussion about some very bespoke solutions. I have 4 switch barrel rifles and have tested three other legacy designs for industry. This is where I've formed my opinion fwiw.

 

[Archimedes]

Why do you think the WTO Switch-lug is necessary in this situation? Why not just screw the barrel on/off with torque?

The industry went through a whole switch barrel gadget craze about 5 years ago and people found out that big zero shifts occured when the barrels took unintended bumps. The way the Switch lug and BARLOC clamped the barrel is albeit similar to an AI but in practice didn't seem to execute the idea in the same way. Maybe because it's a separate piece that doesn't have the barrel torque keeping it planted. Same for the Terminus style grub screw. The action face on those isn't floating with minimal clamping torque from the barrel shank. It's the action itself. And even AI owners found that a higher clamping bolt torque or even a bit of barrel torque (above and beyond what AI instructions state) improved the return to zero and rigidity of a mounted barrel.

Obviously you're going to do what you want, but imo the WTO SL is extra expense, makes those three barrels proprietary, and requires forever future barrels intended for that action limited. And it does a worse job than just screwing the barrel on with some torque. The way that joint was designed.

Clayton is an absolutely awesome dude. Just my opinion on a technical discussion about some very bespoke solutions. I have 4 switch barrel rifles and have tested three other legacy designs for industry. This is where I've formed my opinion fwiw.

Hmmm well besides the extra expense and the proprietary nature of the switchlug, would you say that it does what it claims to do? Easy hassle free barrel swaps without the need of go no go gauges with minimal POI shift?
I’m not opposed to do the traditional method but that would also involve the extra expense of 3 custom sets of gauges.

Also, do you have any thoughts on Remington 700 actions from pacific tool and gauge for 338 lapua?

 

[cas6969]

I’m not sure if that’s just fuddlore....

So you're slighting people for not knowing something you're saying you don't know yourself?
Good luck with your pistol, make sure you buy a good brace.

 

[Mike Casselton]

Hmmm well besides the extra expense and the proprietary nature of the switchlug, would you say that it does what it claims to do? Easy hassle free barrel swaps without the need of go no go gauges with minimal POI shift?
I’m not opposed to do the traditional method but that would also involve the extra expense of 3 custom sets of gauges.

Also, do you have any thoughts on Remington 700 actions from pacific tool and gauge for 338 lapua?

Why would you feel the need for gauges?
Once the barrel is fit to the action, it's gonna go on the same way every time.
Torque them to 80 lb/ft and rock on.

If you're concerned about that, put a witness mark on the barrel and line it up with a receiver facet.

 

[JR1200W3]

Hmmm well besides the extra expense and the proprietary nature of the switchlug, would you say that it does what it claims to do? Easy hassle free barrel swaps without the need of go no go gauges with minimal POI shift?
I’m not opposed to do the traditional method but that would also involve the extra expense of 3 custom sets of gauges.

Also, do you have any thoughts on Remington 700 actions from pacific tool and gauge for 338 lapua?

If durable zero retention is part of the job, I'd say it could be dubious.

You don't need gauges to screw a normal shouldered barrel off and on. Any more than you do with a SL. It's the same process up until you tighten the clamping screw on the SL. You would instead apply torque to the barrel using one of three methods. Shooters choice: AI style wrench flats and a crescent wrench, strap wrench, barrel vise and action wrench. The difference between the three is the amount of torque you want to apply to the barrel and where you want to swap the barrels.

I would advise against both PT&G and a Rem 700 action for any build, regardless of cartridge or caliber. PT&G has a trail of tears and burnt bridges strung behind them from terrible customer service. For years. The only way a R700 action is economically worth it is if you plan to do nothing to it and you pay $400 for one. As soon as you pay more and/or start paying for additional gunsmith enhancements like timing the bolt, bushing the bolt face, side bolt release, upgraded pin and spring, threading bolt knob, truing, coating, etc you can buy a Zermatt long action Origin for the same price or maybe just a tad more and have an ultimately better product and potentially much greater resale value. Plus the Origin has the added advantage of swappable bolt faces for later and cheaper customization. You'd have to research but I don't think they make Lapua sized actions would be the hitch there. But the same argument applies R700 vs custom action.

A big caveat to the above ref actions is you want a switch barrel. For this purpose I would avoid any floating recoil lug design. This is the only time where I think an integral lug has a huge advantage. If you're going to use a barrel vise and action wrench, and you don't mind rezeroing, a floating recoil lug would probably be fine. But if you want to do it in the field and expect a semi precise return to zero (like 1/2 moa) I would eliminate variables and go with an integral lug. This is related to my opinion on the "bolt on" BARLOC/ WTO SL disadvantages.

 

[JR1200W3]

Why would you feel the need for gauges?
Once the barrel is fit to the action, it's gonna go on the same way every time.
Torque them to 80 lb/ft and rock on.

If you're concerned about that, put a witness mark on the barrel and line it up with a receiver facet.

The only way the barrel won't go on the same way is when you use a trued R700 action where the threads were chased and are now larger with a prefit barrel and the threaded joint is super loose up until you torque it. Variable headspace. I learned that the hard way. That was my last R700.

 

[Taylorbok]

could do a 300 NM instead of the RUM save yourself the bolt face difference.

I concur that it's just as easy to skip the WTO lug and just screw on and off shouldered barrels

 

[Mike Casselton]

The only way the barrel won't go on the same way is when you use a trued R700 action where the threads were chased and are now larger with a prefit barrel and the threaded joint is super loose up until you torque it. Variable headspace. I learned that the hard way. That was my last R700.

You shouldn't be using standard threaded barrels on a receiver that has had the threads opened up.

As you pointed out, you found out the hard way.

It wasn't the fault of the receiver. It was simply not knowing that opened up receiver threads are incompatible with all factory and prefit barrels.

You can true a 700 and leave the threads factory. Then you don't have the fit issue with factory and prefit.

 

[JR1200W3]

You shouldn't be using standard threaded barrels on a receiver that has had the threads opened up.

As you pointed out, you found out the hard way.

It wasn't the fault of the receiver. It was simply not knowing that opened up receiver threads are incompatible with all factory and prefit barrels.

You can true a 700 and leave the threads factory. Then you don't have the fit issue with factory and prefit.

Agreed. What makes it worse is that I ordered a barreled action from a very well known gunsmith that sold the "trued 700, plus options" as group buys for years and that's what I received. When you ordered the barrel with the action as an option, they chambered and threaded on a program. I didn't know that at the time and I also didn't understand how that could be a problem until a very talented smith that worked with said group buy guy in the past showed me what the problem was and why the barrel wasn't returning to the same headspace after removing and installing. I had additional problems like cerakote over spray down in the bolt body causing light strikes until we cleaned it out and a huge void or wrinkle/ crack in the feed ramp (likely a manufacturing defect). That barreled action went on down the road and I never looked back. Been custom actions since.

 

[Mike Casselton]

The normal thing to do is to go with the oversized barrel tenon to match the new receiver threads.
I have only one action that has had the full treatment. It has two barrels.

If I need any more barrels for it, they have to be made to fit the oversized action thread.

Thankfully, when I had that done 25 years ago, I was already aware of the issues.

I have other 700s, but they have kept their factory threads.

I mostly shoot custom actions now because life is simpler that way.