Headspace Gauge.....

[MaxxxLogan]

I'm in the process of building an absolute headspace gauge that will have a resolution of 1micron, and a repeatability of 3micron. Over kill I know, just with the setup I'm using it is possible to do so, so I figure why not.

Only one gauge would be required and it will give you an absolute HS value relevant to the case in question. It will also tell you if you are over or under and by how much, handy for adjusting and fine tuning. You can measure your brass and close your HS to any degree you wish. And being such a fine resolution you can monitor any change in HS (if any) over the life of the barrel.

Now, being very new to the idea of F Class shooting, the question I have is, would such a device be something that target shooters would be interested in?

Cheers.

[Guest]

Probably not because cases vary in HS as they come out of the rifle and after running thru the die, by anything up to a thou or so, and I could not imagine anyone making minute adjustments to their sizing die to keep HS on many cases to within a few microns. It would drive you nuts.
Barry

[MaxxxLogan]

Was considering switch barrel applications, hence the repeatability. In building a rifle with two or three switch barrels this would be a great system to build the setup. Was more thinking in matching the case HS to chamber HS during the build of the rifle. Many comp shooters in the US seem put 100-500 rounds through the barrel, then reload and use the same brass for comp. Effectivly fire forming the cases to reduce the HS to a min. Got talking to some US guys and they only use their brass once in a comp, after the initial fire form they reload for comp, use it all up and then get rid of the brass, they say it improves consistency on the longer range comps.

Also working on a device to measure graphically the harmonic vibration in a barrel during a shot, to be able to locate the nodes and tune a barrel with some insight.

[ned kelly]

G'Day all,
if your gunsmith is good enough you should be able to use the same cases in your switch barrelled gun.

In my case with my BR rifle, I use the redding competition shellholder set and measure headspace with the stoney point inserts for their OAL gauge. With the shell holders and a Redding FLS S type die and neck bushing, I size down for 0.002" reduction maximum or until bolt closure is easy on a sized case (firing pin assembly removed from bolt). Never had a problem, just remember which shell holder you need for each barrel and a quick check each time avoids excessive headspace from FLS'ing.

Or more simply, have a batch of cases for each barrel, then you'll have no problems provided they are clearly identified as to which barrel they are fired in.

hope this helps

Cheerio Ned

[AlanF]

I have just bought a Redding gadget called an "Instant Indicator". It works in a press, and amongst other things, allows very quick comparisons of case length (from head to the shoulder face), with measurement estimation to about 0.0002" via a dial gauge. They provide a dummy case as a reference. Works well.

Alan