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anyone with a go-nogo-field gauge set for 300WSM?

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03 August 2005, 17:42
Jameister
anyone with a go-nogo-field gauge set for 300WSM?
If anyone has a set of these headspace gauges, can you mike the lengths and report the difference in lengths?

appreciate it.
03 August 2005, 19:06
flaco
Jameister-

The length of the no-go gauge won't do you any good. Standard chamber headspace is measured off some point on the shoulder.

Why don't you get some books?

I mean if you want to start tuning rifles.

Kuhnhausen has books on almost everything.

Personally, I'm a little mystified as to how you could remove the abrasive after lapping the lugs. Without removing the barrel.

Still, I applaud your effort.

Your idea of adding paper to the base of a cartridge is, I believe, commonly done.

Have you given up on sending the rifle back to the manufacturer, as you mentioned in a previous post?

flaco

Also, you should be able to find the shoulder datum point headspace dimension somewhere.

I'd suspect your present chamber will fall within the limits of the more generous field gauge dimension.
03 August 2005, 19:28
flaco
My apologies, Jameister-

I didn't read your post all that well. Too early, no coffee. LOL.

There's a standard difference between the length of no-go and field gauges.

This should be easy for anyone who deals with them on a daily basis. I'm reluctant to quote anything, as my memory isn't all that good.

flaco
03 August 2005, 19:39
Jameister
Thanks for the suggestion. I looked up the shoulder datum point for the 300WSM. it is a mysterious point marked partway down the shoulder of the chamber. Perhaps you could suggest a way to measure that in a barreled action? however, the machinists that make the go-nogo gauges machine in a certain number of thousandths of inch difference. whereas I know the distance at the base of my cartridge to have .018 inch clearance from teh bolt to the brass, I believe someone haunting these boards either knows or can measure the difference between the go-nogo-and-field gauges at a relevant point with a micrometer or caliper.

As to removing the lapping compound, I used the same abrasive compound that is in the fire-lapping kit sold by Brownells or midway. THat compound is meant to be rolled onto/into the exterior of a bullet that is then seated and shot from the rifle. I used a good wiping and swiping and liberal cleaning in the lug area, much as done after using JB bore paste.

I will send it back to the manufacturer, but since I have three of these, and they are each a bit different on headspace as measured by the number of shoot-n-see (each of which is about .006), I am wondering on the measureements so I can determine my position relative to reasonable warranty request. (if it was made too long, then they pay) or my mistake (I pay). I am asking for knowledge and information. Guess I could buy a set of head space gauges, but I am trying a cheaper way: SHOOT-N-CEE stickys. One should fit and three should not fit. How is that for enough information to be dangerous?

For the person that has these gauges, there is a place a measurement can be taken, else there would not be a way to machine them.
03 August 2005, 20:08
Rick 0311
Jameister,

Call Dave Mason at Mason Precision Reamers...he is the nicest and most helpful guy you can find, and he can give you the info you are looking for, and you can take what he tells you to the bank.

(810) 953-0732

http://www.mansonreamers.com
03 August 2005, 21:04
Jameister
Got it.

1.7316 for go
1.7376 for NOGO
1.7416 for Field

with a net difference of .010 from go (which must allow for some .005 or so for variation between brass makers) to field maximum length, I believe my .018 headspace is problematic. Course I already know that cause of the misfire.

J
03 August 2005, 22:15
flaco
Jameister-

Here's the link to Steve Wagner's site: http://www.gswagner.com/

In a way, he's the antithesis of the AR crowd: His specialty is turning dross to gold. No exhibition rifles there.

Still, he's an amazing craftsman, and you could do worse than spending a couple of days going through all his informative posts.

Somewhere in there is a sweet riff on headspace. I'm not certain everyone agrees with his point of view, but he is very, very well informed. And, I believe, an engineer.

Not to mention more than a few have successfully followed his excellent instructions on bedding Mausers.

flaco
03 August 2005, 22:20
jeffeosso
as a rule, a go is .005 shorter than a no-go.

jeffe


opinions vary band of bubbas and STC hunting Club

Information on Ammoguide about
the416AR, 458AR, 470AR, 500AR
What is an AR round? Case Drawings 416-458-470AR and 500AR.
476AR,
http://www.weaponsmith.com
04 August 2005, 01:46
Tailgunner
Jameister
Not actual dimentions, but more of a referance for you
Cartridge Min length -.012
Cartridge Max length -.002
Chamber Min (GO) 0.0000
Chamber Max (No-GO) +.006
Field Reject gauge +.010
Now, considering that you forced the bolt closed on your brass with stickers, the result dosn't mean squat as you forced the shoulder back. Considering that your brass could easly be .012 shorter than a min chamber and .018 shorter than a max chamber just how accurate a measurment can you expect to obtain using that methiod?
Buy a GO gauge only, add shims to it until the bolt closes 1/2 way under it's own weight (remove the extractor and ejector first, as they will screw up the results). The total of your shim pack will be the amount (over minimum) of headspace that you have.
04 August 2005, 01:54
Jameister
quote:
the result dosn't mean squat as you forced the shoulder back.


I do not believe the bolt had engough resistance to "force the shoulder back" matter of fact, the pressure did not take off the black layer on the shootnsee.

but I do appreciate your suggestion that the brass may be short, not the chamber long. Its a bit of a stretch for me to think Winchester does not make their own named ammo long enough to safely fill a chamber, but with no way to check, who knows.

All I know is on one round, the firing pin pecked at the primer, but it was a dud. second time on the trigger it went off, but not to good point of aim. Doubt it was me, although at times I do know when I pull a shot. That is when I checked out the headspace as measured from teh bolt head to the brass bottom.
04 August 2005, 02:50
fireball168
quote:
I believe my .018 headspace is problematic. Course I already know that cause of the misfire.

J


So a misfire is the root of all these posts?