7-08 Go/No Go Guage

[RedRidge]

Looking for some 7-08 go no go guages to borrow if anyone is willing to lend them out. Thanks

 

[pods8 (Rugged Stitching)]

I got the forester go gauge for 243-308win (which covers 7-08) and just use the tape method for no-go.

 

[HandgunHTR]

I got the forester go gauge for 243-308win (which covers 7-08) and just use the tape method for no-go.

Same. EABCO has them for $32.

 

[Marbles]

I buy no-go gauges and use brass as the go gauge. I figure the no-go is most important to be correct from a safety stand point.

If doing a barrel nut install you will probably want a go gauge though.

Anyway, not much help for what you actually want.

 

[Mountainrancher]

308 Winchester Headspace Gauges

 

[HandgunHTR]

I buy no-go gauges and use brass as the go gauge. I figure the no-go is most important to be correct from a safety stand point.

If doing a barrel nut install you will probably want a go gauge though.

Anyway, not much help for what you actually want.

In actuality the field gauge is the most important from a safety standpoint, but nobody ever uses them.

 

[RedRidge]

Thanks all. I recently swapped a barrel on one of my tikkas and just need to check it.

 

[Marbles]

In actuality the field gauge is the most important from a safety standpoint, but nobody ever uses them.

No, field gauges are the absolute end of safety, they will show good to go status when a no-go will not. Outside of keeping weapons in service in an actual war, a field gauge should not be used in my opinion, particularly by people who hand load as so many are already running over pressure.

There is a reason nobody uses field gauges.

 

[HandgunHTR]

No, field gauges are the absolute end of safety, they will show good to go status when a no-go will not. Outside of keeping weapons in service in an actual war, a field gauge should not be used in my opinion, particularly by people who hand load as so many are already running over pressure.

There is a reason nobody uses field gauges.

I think you may be confusing the two. The go-gauge is SAAMI minimum. The no-go is SAAMI minimum +0.005 or 0.006" (depending on manufacturer), the field gauge is SAAMI +0.010. If your bolt closes on a field guage you are at the absolute maximum headspace (or over). You still have "safety" room even if it closes on a no-go.

 

[Marbles]

I think you may be confusing the two. The go-gauge is SAAMI minimum. The no-go is SAAMI minimum +0.005 or 0.006" (depending on manufacturer), the field gauge is SAAMI +0.010. If your bolt closes on a field guage you are at the absolute maximum headspace (or over). You still have "safety" room even if it closes on a no-go.

No, I'm not confusing the two and your own numbers prove it. Outside of war, if your bolt closes on a NO-GO gauge you should stop using the rifle. There is not "safety room" you are unsafe. Unless the cost of not shooting that rifle is more than the potential cast of loosing part of your face, there is no "safety room." You needing to add the "(or over)" lines up with this.

A NO-GO gauge says the chamber is safe for any round within spec, the field gauge says the chamber may result in a case head separation with cartridges that are at the minimum spec, but some cartridges will still be safe.

If you are happy shooting a chamber between NO-GO and field, you are free to do so. I will not be unless very important things depend on it.

 

[HandgunHTR]

No, I'm not confusing the two and your own numbers prove it. Outside of war, if your bolt closes on a NO-GO gauge you should stop using the rifle. There is not "safety room" you are unsafe. Unless the cost of not shooting that rifle is more than the potential cast of loosing part of your face, there is no "safety room." You needing to add the "(or over)" lines up with this.

A NO-GO gauge says the chamber is safe for any round within spec, the field gauge says the chamber may result in a case head separation with cartridges that are at the minimum spec, but some cartridges will still be safe.

If you are happy shooting a chamber between NO-GO and field, you are free to do so. I will not be unless very important things depend on it.

Ok, now I understand what you are saying. I am sorry I missed it on the first go round. Completely my fault.

When I say "safety room", what I meant to say was that even if your bolt closes on a no-go, your chamber could still be within SAAMI specification, which is the ultimate determiner of if it is safe or not.
I went back and checked a few chamber drawings, and I was incorrect in my statement that if your chamber closes on a field gauge you may still be in spec. That is not true. Every drawing I looked at had a maximum headspace dimension and between -0.006 and -0.008" of tolerance. Therefore a gauge with +0.010 will always be over SAAMI spec. However if the chamber is cut to minimum +0.006, it is still within SAAMI spec, yet a no-go will still fit.
I get that it may be a bit pedantic, but I am a bit of a stickler for fine details.

Now to get back to the OPs question/comment, as Marbles pointed out, if you are doing a barrel nut install you should use a go gauge to set the headspace and a no-go to check to make sure you are not over. A piece of brass used as a go could result in a chamber that is too small as most virgin brass is a few thousands below minimum to ensure that it will fit in all chambers, but it isn't consistent between manufacturers. If it is a shouldered prefit, then if your brass chambers and it won't close on a no-go, you are golden.

 

[pods8 (Rugged Stitching)]

IMHO I like the go gauge and tape because with a caliper I can tell how much over the go guage the chamber is. So far the limited prefits I've put on have been very tight to chamber minimum, a single 0.0025" layer of tape was enough to prevent bolt close. That provides two useful data points versus the no go gauge just not being able to close.