Forster Head Space Gauges

I

iraiam

New member
Anyone have Forster Head Space Gauges? I have a couple new 30-06 gauges that I bought for a project that I'm going to be doing.

Problem is, I think the No-Go gauge is not quite right. it's marked 2.0547, because the Forster gauges use a different datum line than other brands. I have checked known good rifles against this No-Go gauge and they all fail.

Remington 721 30-06, closes fully on No-Go gauge
Remington 700 .270, closes fully on same gauge
Remington 700 25-06, almost new rifle, closes fully on the same gauge.

I made .001" and .0015" shims out of SS shim stock and tested all 3 rifles again with each shim separately installed, with the .001" shim added the bolt is stiff to close, I could close it all the way but I did not. With the .0015" shim installed the bolt has a positive lockup well before closing. All three rifles are virtually identical.

I have been unable thus far to get an exact measurement on the diameter of the shoulder at the datum on the No-Go gauge. but just the fact that all three factory rifles are identical with this gauge leads me to believe that the gauge is not quite right.

What do you think? Right now I'm leaning toward returning it.

Guess I'll have to make a jig that I can install the gauge in to get an exact measurement from the datum line on the shoulder.
 
Last edited:
Well I answered my own question, although the gauge is marked NOGO it is actually a GO gauge:mad: it measures 2.0485" from datum. .0005" is as close as I can measure with this setup.
 
chaange to go-gage length

First:

“Problem is, I think the No-Go gauge is not quite right. it's marked 2.0547, because the Forster gauges use a different datum line than other brands.”

Then:

“Well I answered my own question, although the gauge is marked NOGO it is actually a GO gauge it measures 2.0485" from datum. .0005" is as close as I can measure with this setup”

2.048 is minimum, 2.058 is maximum ‘SAAMI says’,

I will assume your set up is based on the datum/round hole diameter of .375”. If you had a L.E. Wilson case gage, a straight edge and a few of those stainless shims you could verify the gage.

Then there are methods and techniques that could be used. A no go-gage can be used to measure the length of the chamber in thousandths without the shims, same with the field reject gage. And it is possible to modify a go-gage to measure the length of a chamber from go-gage length to infinity, PROBLEM: Reloaders sound like an an episode of ‘WELCOME BACK COTTER’ the ‘I AM SO CONFUSED’ episode, being confused is OK, blaming someone else is not.

F. Guffey
 
Last edited:
Then there is the possibility of carrying one thought all the way through the process, use the head space gage to check the L.E. Wilson case gage, use the head space gage to check the full length sizer die, before everyone ask how? I will explain. Remove the primer punch/neck sizer assemble from the die, then insert the head space gage into the die, then relax and take a breath, those that are good wild guestimaters can guess the go-gage protrusion, those that have and are familiar with how to use a dial caliper can measure the gage protrusion from the die, for the 30/06 in the perfect world the protruding go-gage should measure .130” from the die. For those reloaders that have a ‘tad’ measuring equipment, I do not know, ask them.

Why .130” protrusion? The shell holder, the deck height of the shell holder is .125, then there is the add factor as in the difference in length between the minimum length/full length sized case and the go-gage length chamber, the difference is .005 in the perfect world.

Additional step factor. With the primer punch/expander ball assemble removed install the die into the press but do not screw it down to the shell holder, after installing the die insert a go-gage into the shell holder and raise the ram, after the ram is up screw the die down to the go-gage (CAREFULLY) until it makes contact with the gage.

After contact measure the gap between the bottom of the die and top of the shell holder, in the perfect world the gap will be .005”, the gap can be measured with a thickness gage also referred to as the companion tool to the press, the feeler gage.

For those that have used a grinder to remove metal from the bottom of the die and or top of the shell holder will have results that varies.

F. Guffey

_______________________________________________________________________________________________________________________________________________________________

Tad AND Thag, I was curious about the spikes on the tail of a prehistoric animal, so I ask. I caught the old professor in a bad mood (I think). He called the spikes Thagerizers, not satisfied I ask how would an animal get a name like that for parts on his tail, The old professor claimed there was a cave man named Thag that was warned to quit aggravating the prehistoric animal with the spiked tail, he didn’t, after that day friends of Thag called the spikes THAGERIZERS.
 
Yes, I made a measurement jig with an exact .375 hole bored into it, put the gauge in it and measured the height with a depth micrometer and got 2.0485".

Last night I machined my own NoGo gauge that measures 2.054", I could just use the shims but it was simple to turn on a lathe, I turned out of O-1 drill rod, I'll harden and temper it tonight.
 
I am impressed, save the plate with the .375" hole, with small modifications it can be used to measure case length from the .375" hole to the head of the case.

F. Guffey
 
I would take a picture of it, but my camera is in my laptop bag at work and this is my weekend.

It's just a round piece of cold roll, 1" in diameter. there is a hole bored through the center at 2 different diameters, one at 0.375" and 0.475".

A 90 degree section of the jig is machined open down to the same depth as the start of the 0.375" diameter hole to accept the plunger of the depth micrometer. It just measures the distance between the 0.375" hole and the base of the gauge.

Now that I think about it, it's far more complicated than I needed it to be, a simple flat plate with the proper size hole in it would have done the job, I just made it this way to make it easier to hold the gauge while I measured it.
 
You must log in or register to reply here.
Back
Top