Built-in headspace gauge on switch barrel ?

[Hammer]

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Mere casual speculation without any actual attempt to use or serious thought given nor check of accuracy, numbers, or arithmetic…


Savage barrels have 20 threads per inch.

One complete turn of the barrel moves headspace 0.050 inches.

1/25th of a turn moves headspace about 0.002 inches.

Some think that industry headspace tolerance is normally 0.004 inches.

If we were to put 25 dots or marks engraved (punched) uniformly spaced around the barrel just beyond where the barrel nut goes, we would have a built in headspace gauge. (Just like a UniqueTek converted Dillon powder measure.)

We could turn the barrel in tight against any factory or handloaded cartridge we wanted to shoot, and then back off one dot for 0.002 inch headspace.

This would allow variation in cartridge sizing (headspace) without giving us excessive barrel headspace.

If 25 dots are too many for us to handle, 12 dots would produce 0.0042 inches or right at maximum tolerance. (The circumference of a Savage barrel is 3.3 inches.)

Any gunsmith with the most primitive lathe could easily put the dots on the barrel.

Aftermarket manufacturers of Savage ready-to-install barrels could put marks on barrel for us.

Takes longer to explain than to do.

If this will really work, am sure many smart people have already done it.



[Derived from August 2011 Precision Shooting article “You Too Can Have a Switch Barrel Rifle”, by Josh Benin, pages 13 – 25.]

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[bsekf]

Hammer, you have entirely too much time on your hands. However, you are 100% correct. Headspace is not the boogy man, and it is not measured +/-.00001. I do not tighten my barrel nuts very tight and I always put an index mark on the barrel and frame so I can tell if the barrel moves. Guess what, when I remove and put back on the same barrel the index marks line up. ::)

If you want to drive yourself crazier start measuring your fired cases with a comparator.

Bill

[Hammer]

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Hammer, you have entirely too much time on your hands.




Just wish that were the case.

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[okey]

If you want to drive yourself crazier start measuring your fired cases with a comparator.

Bill


I spent two evenings doing that on my 8 twist .223. Winchester cases had 5 firings on them. They varied .004. After annealing and firing they were back to within .001 variance.

Okey

[stangfish]

If you want to drive yourself crazier start measuring your fired cases with a comparator.

Bill


Yup

[airaddict]

How bout welding a barrel nut to the barrel while the headspace is set so all u have to do is snug it down on the lug and action and ur ready to shoot. You would of course have to check headspace periodically but for the most part its the throat that will move over time.

Think it would work?

Brian

[hotbrass]

Weld?

How about just a set screw.

Or if you really want it to stay, just have it pinned.

[airaddict]

I just thought a weld would be easier to clean up and hide or blend in opposed to a set screw or having to drill into the barrel for a pin or something. But i could maybe see a setscrew working to lock the nut in a certain orientation on the barrel to fix headspace to a certain action and lug.

Brian

[geargrinder]

I also use a simple index mark on my barrel and nut when setting headspace. Make adjusting it very easy. I use a sharpie pen.

As for using a setscrew or welding, i thing that is a way more trouble than the solution is worth.

[Aircraftmech76]

I didn't see you mention the headspace created when the thread "slop" is taken out; in this case (IIRC), .0015". This would have to be factored into your index markings.

Kevin

[MikeS in CO]

This is something I have pondered but with a different solution. What about putting loctite under the lock nut only and having a nut for each barrel that is fixed in place more or less permanently. An additional index mark applied to both the barrel and nut after everything was done would provide a reference to check after swapping barrels. I would use red loctite.

I have been lurking for a long time and building for about a year. My name is Mike and I think I have a Savage problem! It has been 10 days since I bought the last one.

[Hammer]

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The pinning, welding, or otherwise fixing the barrel nut to the barrel won't work for me.

The headspace for all my different actions is not identical.

I routinely change both barrels and actions.

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[bsekf]

I didn't see you mention the headspace created when the thread "slop" is taken out; in this case (IIRC), .0015". This would have to be factored into your index markings.

Kevin


Don't all you guys lap the thread "slop" out? Like Virgil King and the guys at the Houston Warehouse. ;D

As Hammer said, this idea will only work if you swap between dedicated actions and barrels.

I use a very sharp punch to make an faint index mark, that way I can buff (grind) it out.

Bill

[82boy]

I think you are on to something. It would be an interesting thing to try.

[Aircraftmech76]

Don't all you guys lap the thread "slop" out? Like Virgil King and the guys at the Houston Warehouse. ;D

Bill
[/quote]

LOL-if you lap the "slop" out, it only creates more slop. Ever hear of the carpenter who cut three times and the board is still too short? :-D

Kevin

P.S.: I remember reading about the Houston Warehouse article in Precision Shooting oh so many years ago. Great article!