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Old 07-21-2015, 8:50 AM
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ar15barrels ar15barrels is offline
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Default Ruger Precision Rifle

Quote:
Originally Posted by jbj View Post
You are right that repeatability will suffer with a nut-and-gauge system. To what extent, I couldn't comment as I don't swap calibers.

I am certain it is not as precise as having Randall cut a shoulder on a barrel, but for many, the variance it might produce in accuracy isn't going to make a difference for what they are doing. I also believe that the floating bolt head of the Savage helps to compensate for some of these variations.

There are many who use a piece of fireformed brass as the go gauge, and a piece of scotch tape on the same piece of brass for the no-go gauge.

What he is talking about is trying to use a nut gun as a switch barrel rifle without having g to re-adjust sizing dies and case shoulders while maintaining neck-sized cases.

On a machined-shoulder gun, the barrel repeats headspace to 0.0001" precision.
There is NO change in headspace.
With a barrel nut, you are adjusting headspace every time so it's not going to be exactly the same.
This means that neck sized cases may need to be full length sized after a barrel swap if the headspace is changed,

With the variation in position of the barrel, the zero is also going to wander between barrel swaps as well.

A proper "switch barrel" setup will have multiple fixed-shoulder barrels.

A barrel nut setup is more appropriate for someone who want to re-barrel at home but is not appropriate for switch-barrel use.

The floating savage bolt head does nothing for headspace variation.
The head floats so that it will follow the receiver and keep both lugs in contact regardless of how straight or crooked the receiver may be.
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Last edited by ar15barrels; 07-21-2015 at 8:56 AM..
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