For Switch-Barrel Guns, How Do You Maintain Accurate Scope Zero?

[tim_w]

IMHO it does not matter what system or how great it might be for repeatability... in a gun meant for killing vs punching paper you ALWAYS should confirm zero by shooting it every time you make a change like barrel swap before ever using it to take game.

 

[jda2631]

If using a Savage, like stated in your first post, i would recommend loctiting the nut to the barrel at the proper headspace and use witness marks. Put the barrel on and test fit, once head space is correct. Back off the barrel nut and add some loctite to the threads and torque nut back down, and of course check again to make sure headspace is still correct. I have also seen someone drill a hole in the barrel nut and use a set screw to "attach" the nut to the barrel. Then put a small witness mark on your action somewhere (could put it on the bottom of the action if you don't want to see it) and put one on the barrel nut as well that matches up. Now, the barrel will act like a shouldered barrel with the nut loctited on, would just need to torque it to where the witness marks match up the next time you put that barrel on. The POI of that barrel should be very close each time its put on. And just do that for each barrel you have, adds a little cost since you need a different barrel nut for each barrel.

As for scope, the best option I have seen for this is with the Vortex Razor Gen II or AMG. With their "infinitely adjustable zero". You would just need to log where each barrel is zeroed on the circular dial of the turret (the piece you turn to zero the scope).

To switch a barrel, you take the old one off, torque the new one down to the witness mark previously made (it will be headspaced correctly but you still need to check to verify!), check log to see where this scope is zeroed, and move the dial to the correct location.

This system isn't perfect, but its going to get you to be very very close to being zeroed after a barrel swap with minimal time and effort (and ammo).

 

[Tidus56]

I am in a similar situation, I have done savages forever and love the barrel nut setup. But I am wanting to change to 2 stocks, 2 scopes and lots of barrels. I want one to be a short action rifle that I will use for varmint shooting and shooting targets. Then I want a long action with multiple bolt faces so I can do magnum and non magnums. I am still thinking I will end up going with WTO setup on a Bighorn action until I see a better option. I have 18 months before I have to worry though, my wife and I are both in grad school. I will check out the ARC Barloc setup.

 

[Tidus56]

If using a Savage, like stated in your first post, i would recommend loctiting the nut to the barrel at the proper headspace and use witness marks. Put the barrel on and test fit, once head space is correct. Back off the barrel nut and add some loctite to the threads and torque nut back down, and of course check again to make sure headspace is still correct. I have also seen someone drill a hole in the barrel nut and use a set screw to "attach" the nut to the barrel. Then put a small witness mark on your action somewhere (could put it on the bottom of the action if you don't want to see it) and put one on the barrel nut as well that matches up. Now, the barrel will act like a shouldered barrel with the nut loctited on, would just need to torque it to where the witness marks match up the next time you put that barrel on. The POI of that barrel should be very close each time its put on. And just do that for each barrel you have, adds a little cost since you need a different barrel nut for each barrel.

As for scope, the best option I have seen for this is with the Vortex Razor Gen II or AMG. With their "infinitely adjustable zero". You would just need to log where each barrel is zeroed on the circular dial of the turret (the piece you turn to zero the scope).

To switch a barrel, you take the old one off, torque the new one down to the witness mark previously made (it will be headspaced correctly but you still need to check to verify!), check log to see where this scope is zeroed, and move the dial to the correct location.

This system isn't perfect, but its going to get you to be very very close to being zeroed after a barrel swap with minimal time and effort (and ammo).

Great idea! This might work for me for the next few years.

 

[jda2631]

I am in a similar situation, I have done savages forever and love the barrel nut setup. But I am wanting to change to 2 stocks, 2 scopes and lots of barrels. I want one to be a short action rifle that I will use for varmint shooting and shooting targets. Then I want a long action with multiple bolt faces so I can do magnum and non magnums. I am still thinking I will end up going with WTO setup on a Bighorn action until I see a better option. I have 18 months before I have to worry though, my wife and I are both in grad school. I will check out the ARC Barloc setup.

I am doing the same idea, although over time I have convinced myself into believing that I need 4 action/stock/scope combos and lots of barrels/bolt heads. 1 long action hunting set up, lightweight more traditional style stock. 1 long action target set up, chassis and not too worried about weight. Then the exact same thing with short actions...

I am going bighorn and shouldered barrels (since they all headspace the same, you can order shouldered barrels straight from PVA or another smith that has made one for a bighorn, without them ever needing the action). That way any barrel I have for a short action, will work for either short action "rifle", same with long action. I don't really think I'll ever want to change barrels out at the range, so shouldered barrels are fine and will change them out at home with a vise. But I have seen people just hand tighten barrels to actions before with no issue. Put stock between their knees and just hand tighten the barrel on and the rifle shot great. These were short action NON magnum cartridges though. 223, 6.5x47, etc.

 

[jda2631]

Great idea! This might work for me for the next few years.

Its a very effective system. Easy to repeat POI from barrel change to barrel change.

 

[kai]

jda2631... I'm using a similar solution. Most of my barrels will have a 1.2 inch diameter shank and a shoulder cut to head space the barrel. I will also be using Savage type prefit barrels (because they're stock items and less costly than custom barrels). On the prefit barrels, I will be permanently installing custom barrel nuts (with no serrations for aesthetic reasons).

Tidus56.... I was also planning on using a Bighorn action and considered the WTO lug. After studying the ARC Nucleus and Barloc, I decided to go with the ARC Nucleus action and Barloc.

I called Vortex and asked about the L-Tec Zero stop. They told me that their feature only sets the "stop" and will not set different zeros for sighting in for different loads/barrels. The Vortex tech person told me that no scope can do that.

 

[jda2631]

.....
I called Vortex and asked about the L-Tec Zero stop. They told me that their feature only sets the "stop" and will not set different zeros for sighting in for different loads/barrels. The Vortex tech person told me that no scope can do that.

I'm not talking about setting the turrets for different zeroes for different loads/barrels. If you take off the top of the turret to zero it. There is a horizontal dial, this is what you actually turn to zero the scope. This is the best picture I could find on a quick google search.

You zero your scope with Barrel #1. You write down the elevation and the windage of where that barrel was zeroed. (i take a picture with my phone and store it, have visual reference of where it is, since it isn't clicked based. It's infinitely adjustable, can get a tad more precise).

You zero it with barrel #2 and do the same.

When you go back to barrel #1 you refer to your notes to see where the windage and elevation need to be set to be zeroed, set them in their corresponding locations and you should be good to go. There will be a POI shift from the barrel change, but it is minimal. If done correctly, your POI shift should be less than .2-.4 mil or so. Most times it is closer to .1 mil.

 

[kai]

jda2631... Thanks for your post and for the photo. I also watched the Vortex video to get an idea of how this zero stop feature works.
As I understand it, the Vortex turret does not keep track of a reference "zero" when making changes and it does not adjust for different zeroes for different loads or barrels.

I'd like to be able to set a scope for a main or "reference" zero sighted in for a particular load, and to then be able to set it with a multitude of alternative pre-established zeroes for different loads and/or barrels.

Hell, for that matter... while I'm dreaming, I'd also like to be able to take a favorite (expensive) scope and remount it onto different guns and then easily reset the zero for the second gun and still be able to move it back to the original gun and easily reset it to the original "main or reference" zero without having to correctly remember how much it had been adjusted previously.

I've paid about $1,500 for a Kilo 2400 that gives me ballistic solutions for 4 different loads...but it doesn't remember or reset the zero for the different loads.

I wonder what people would pay for this type of feature for their scopes.

 

[Tidus56]

jda2631... I'm using a similar solution. Most of my barrels will have a 1.2 inch diameter shank and a shoulder cut to head space the barrel. I will also be using Savage type prefit barrels (because they're stock items and less costly than custom barrels). On the prefit barrels, I will be permanently installing custom barrel nuts (with no serrations for aesthetic reasons).

Tidus56.... I was also planning on using a Bighorn action and considered the WTO lug. After studying the ARC Nucleus and Barloc, I decided to go with the ARC Nucleus action and Barloc.

I called Vortex and asked about the L-Tec Zero stop. They told me that their feature only sets the "stop" and will not set different zeros for sighting in for different loads/barrels. The Vortex tech person told me that no scope can do that.

The thing that matters most to me is that I don't have to take the scope off each time a swap a barrel. It's such a drag to pull it all the way off. It seems the barloc would work for what i would like.
The nucleus picks up the cartridge from the magazine? I am on their website and can't tell if they have the option for a Wyatt's box and a BDL setup, do you know if they do? I have only shot one Mauser and I fed it single shot like I do at the range and it wouldn't extract the cartridge afterwards. So if the nucleus extracts like this I would likely struggle to remember to magazine feed it. Maybe it was a win 70 that did that, I can't remember. I have used mostly Rem 700 and Savages.

 

[jda2631]

As I understand it, the Vortex turret does not keep track of a reference "zero" when making changes and it does not adjust for different zeroes for different loads or barrels.

No purely mechanical scope can do this, you would need some sort of computer/HUD integration. Maybe the Revic scope is the start and will get there one day.

But any purely mechanical scope. You will have to set the zero for a round, remember or write down where that zero location is in the elevation and windage planes, and then return that reticle to that location in the scope (zero it) after it's been moved to another load/barrel's zero. The L-tec turrets are the easiest turrets to deal with multiple zero's that I know of.

 

[MagnumManiac]

After re-reading all of these posts, there is a hell of a lot of pipedreams going on here.
I have zero-stop scopes and scopes without zero-stops, NONE of them will be on song when changing barrels, some re-zeroing/sighting will/is necessary. Just like 2 different loads rarely shoot to the same POI without some adjustment to the scope.
I have fired a 10 round group, removed the barrel, put it back on and HAND TIGHTENED it and had less the a 1/4" shift in POI, then had no shift when doing the same with a barrel vise/action wrench just nipped up past hand spun. Have repeated this several times, each time the result was a little different, but not much more than described
I have a self set rule that any one action/stock combo can only utilise a max of 3 barrels in different cals. To use more only compounds the difficulty in keeping track of the different zeros. I'm sure more could work, but for me, 3 is max. I must emphasise this is in regard to hunting rifles, not target rifles, which generally is a different kettle of fish. I have to remove stocks to change out my hunting rifle barrels, so this another factor in POI change.

Hell, even my F-Class rifle that has 3 barrels in 300 WM and 3 barrels in 264WM is hard enough to keep track of. All 6 barrels have the same headspace governed by the barrel shoulder, and all have less than .001" runout when on the action and spun in the lathe, yet they all shoot to slightly different POI. All of these barrels go in 26", 28" & 30" for different F-Class ranges and conditions. None use precisely the same load either.
The closest set of barrels I run is my 6.5x47 Lapua, changing barrels only shifts POI .2MoA, the same load in both barrels is used, I believe this is why the POI doesn't shift all that much in this rifle. Also, these rifles are permanently bedded and the barrels come off without the need for disassembly.

I like your ideas and theories, but just think you are asking for something that just isn't feasible, especially in regard to switching loads in a barrel and having a scope that can track upteen number of zeros.

Cheers.

 

[kai]

Titus56... The nucleus is made to only use magazines, not BDL magazine boxes. I checked with them at SHOT Show and they weren't sure if the Nucleus would accept the long AICS mag. It's close, so I'll have to test fit the bottom metal and a long mag to see once the Nucleus action is available. I handled the Nucleus and like the way it extracts the cases and ejects them mechanically without using a spring loaded plunger in the bolt.

 

[Tidus56]

Titus56... The nucleus is made to only use magazines, not BDL magazine boxes. I checked with them at SHOT Show and they weren't sure if the Nucleus would accept the long AICS mag. It's close, so I'll have to test fit the bottom metal and a long mag to see once the Nucleus action is available. I handled the Nucleus and like the way it extracts the cases and ejects them mechanically without using a spring loaded plunger in the bolt.

Thanks for the info