Used or new from factory barrel fit

[Rangeball]

I know there was a thread here recently that addressed how often used barrels lock up tight on a given action, and the results were anything but plug and play.  The tips address how to fit a used barrel, and H&R will do it on a new one, but is it the underlug or the action itself whose tolerance are usually at play in getting a barrel to lock up tight, or a random combination of both?

[cwlongshot]

Take a look at the top of this page, look for a thread labeled FAQ's. There is a section of fitting barrels.

The search is quirky sometimes, unless you have author and exact thread name its hard to locate threads.

CW

[Rangeball]

I saw that, but unless I'm missing a thread somewhere I didn't see anything that dwelved into what I was asking.  Not being able to fit up off the shelf like an encore has to be related to less than tight specs.  Is it usually the underlug, the pin or the shelf or no rhyme or reason?

I guess where I'm headed is wondering if there is a way to take specific measurements of an action and barrel/underlug to see if it is likely to lock up tight?

[cwlongshot]

Don't look at it as if it relates to the encore/contender. It dosen't.

Adjustments done to fit a barrel to a receiver are done to the barrel, not the receiver. Generally the barrels shelf needs to be stoned or the "hinge" pin shimmed. Again the rule is nothing is done to the receiver, only alterations are done to the barrel.

CW

[necchi]

Well yer only talking .002 -.003 here,,and it's the underlug,,usually not the pin. But because the underlug is on a different horizontal plane than the breech face, I don't see how a diagonal measurement could be made to that kind of accuracy.

 I spose a feller could fit a .375 rod in the underlug groove and measure from that,,I guess I just never thought I'd need to measure first before actually fitting,,It either will or won't. Modification to the underlug will be needed to remove or and material there if the case is it won't fit.

go back to the faq's and read freds accuracy fitting info,,he's done some very precise measurments

[Rangeball]

Thanks Fellas

[gcrank1]

You could make a jig with a rt. angle block and a .375 pin to trial fit barrel into but it would work no better than carrying around your action, since that is what you ultimately have to fit to. Briefly,
Two issues: 1) lug to breech face fit (and susequent headspace), both 'givens' on a certain frame
2) shelf and latch for lock up (and take care that the release is 'free' when the barrel is seated)
Did I miss anything else, guys?