How many thousandths does a Mauser mod 98 barrel "take-up when tightend from contact with shoulder to fulley tightened??
Or to look at it another way, typically what part of 360 degrees will it take to accomplish?

"Or to look at it another way, typically what part of 360 degrees will it take to accomplish?"

Not much. A 1-12 thread has a pitch of .083, that's how far it moves each turn (1/12). You normally figure .002 crush, "contact to fully tightened".

.083/.002=41.5

Divide the 360 degree circle by 41.5 and you come up with 8.67 degrees. Not much.

Or you could figure it by distance on the circumference of the barrel, 2 x pi x radius.
Figuring a barrel diameter at the action of 1.2" , you get a circumference of 3.77" . Divide that by 41.5 = .090 . If you draw a line connecting the action and the barrel when contact is first made, at .002 crush the lines would be .090 apart.

The only time I go through all this mental gymnastics is when I'm trying to clock in a barrel that has sights or letters that I want to come out right. If you're putting on a new barrel, make contact with the shoulder, then give the action wrench a solid whack with the palm of your hand. Then say, "there, .002 crush".

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The only time I go through all this mental gymnastics is when I'm trying to clock in a barrel that has sights or letters

Or timing flutes.

Thanx, the 0.002" crush is the number I was going for. Figured I would get the number direct or by calculating the way you did if someone gve me the approximate amount the barrel turned.
I have a barrel I need to fit and since it closes on a no go, I can see at least 5-7 thousands coming off. Maybe a bit more and then treat it like it was short chambered and cutting the last little bit out (again).

I'd figure out how much over it is by putting masking tape on the back of the no-go. Measure the thickness of the tape by taking a piece, folding the sticky to the inside, measure the doubled piece, then divide by 2. It should be in the range of .004-.0045 for a single piece. Keep adding tape until the no-go is a no go. Adding that many pieces plus 1-2 more to the go gauge should keep it from closing. That works as a good double check.

That method gives you a number to cut to instead of guessing, cutting & checking. That method works too but has a significantly higher sphinctor factor.

If you do this carefully, you should be able to hit it on the nose. No reamer work necessary.

Mark,

I just noticed that you are in Liberty, Mo.

I did a movie there years ago and it is one of the prettiest places I have ever been...and with some of the nicest people you will ever meet.

I envy you!

Rick

Might also want to contemplate that some barrels seat from firing a thou or two, as well. FWIW, Dutch.

quote:

Originally posted by Rick 0311:
Mark,

I just noticed that you are in Liberty, Mo.

I did a movie there years ago and it is one of the prettiest places I have ever been...and with some of the nicest people you will ever meet.

I envy you!

Rick

Just don't tell anyone. It's already getting crowded around here. I live about 5 miles outside of town. No need to move to town, it's moving to me.

My 2 cents worth...the 2 thousands figure is correct...also using tape on the no go is good...
I use tape that is 4 thousands...try one layer,
then another.
Best Regards, Tom