Head space gauges

[PaddyD]

I know I should use both, but can I get away with simply screwing a barrel onto a go gauge or must I go out and also buy a no go gauge?

[celltech]

I personally just use a go gauge and then add a 3 thou shim as the no go. Plenty of people never use both...

[Robinhood]

I agree. I use scissors to cut out a cola can shim and fit it to the inside of the bolt head for no go.

[celltech]

If you want an assortment of shims to play around with buy a cheap spark feeler tool for $6 and start cutting.

[mudpig]

Piece of scotch tape is about .002. That's all that is really necessary with your GO gauge.

[DesertDug]

I have been using both. Ya it more or a cost, but much easier to go back and forth into the chamber while getting everything together. This is such a critical part of doing it right, I want to know my tools are correct and not a hack.

[thaifighter]

all of the above tricks will work, right up until they dont... It never made financial sense to me to risk being out of spec with something that's exploding inches away from my face...

[Robinhood]

all of the above tricks will work, right up until they dont... It never made financial sense to me to risk being out of spec with something that's exploding inches away from my face...

I'm sorry if I find this amusing. How many rifles have you seen that were destroyed by head space being a few thousands out of spec? ZERO.

Misinformation is all over the internet. You could present your position like below but implying that there is going to be a catastrophic event is somewhat irresponsible.

If head space is too short the bolt will not close so it can't be fired. If it is too long it will either have a light primer strike with no ignition or it will ignite and push the primer out.

The worst case scenario would be case head separation but there would be other factors involved. Similar to over sizing brass.

There is no magic here. Head spacing is a dimensional thing. The No Go gauge has an increased length from the base to the datum on the shoulder. It will indicate that the chamber is correct by the bolt not closing or excessive if the bolt does close. A well thought out shim accomplishes the same thing with the exception is that you can control the length separation between the go and the no go. The only thing is you need to have some kind of understanding of small differences in dimensions and how to check them.

Change my mind.

[wbm]

+1.

[varget204]

I buy the MANSON Go Gages,think they are more consistant,like others,i do not buy No-go gages,i use apiece of .001-.002 paper/tape/ or shim stock on back of Go gage for the No go,I want minimal headspace in my barrels.Not interested in .005-.010 headspace.Am looking for most accuracy i can get out of any caliber i load for.Brass lasts longer the less you have to bump shoulders.The $ 35 plus shipping i save for the No go,i use to buy for componets

[thaifighter]

Glad I could be a source of amusement for you...

and I don't need to change your mind. If you are comfortable with 50k CUP that close to your face and eyes utilizing eyeballed specs to save a few bucks, knock yourself out. Modern metallurgy and machining has spared an awful lot of people that Darwin would have otherwise swept off the chessboard.

You talk about case head separations as if it's an ok thing. I back off when I start seeing primers bulge or extractor swipes. You are wrong about the bolt not closing, depending on the force behind the bolt (and I close mine with authority) and the charge, you jam the lands and force the bullet back into the case when you are short on headspace and light on neck tension. Try that with a fast burning powder near maximum load and there's your hunky-dory case-head separation.

I don't need to see injured people and wrecked receivers on the interwebs to prove what I know. I am an engineer by profession. I don't fool with physics. I control as many variables as I can and using a precision machined tool to set headspace is one of them.

You go do whatever you do...

and unless you know the OP's educational background, skill with tools and generally building anything, the responsible answer is to tell him to use a proper gauge...


I'm sorry if I find this amusing. How many rifles have you seen that were destroyed by head space being a few thousands out of spec? ZERO.

Misinformation is all over the internet. You could present your position like below but implying that there is going to be a catastrophic event is somewhat irresponsible.

If head space is too short the bolt will not close so it can't be fired. If it is too long it will either have a light primer strike with no ignition or it will ignite and push the primer out.

The worst case scenario would be case head separation but there would be other factors involved. Similar to over sizing brass.

There is no magic here. Head spacing is a dimensional thing. The No Go gauge has an increased length from the base to the datum on the shoulder. It will indicate that the chamber is correct by the bolt not closing or excessive if the bolt does close. A well thought out shim accomplishes the same thing with the exception is that you can control the length separation between the go and the no go. The only thing is you need to have some kind of understanding of small differences in dimensions and how to check them.

Change my mind.

[Robinhood]

Glad I could be a source of amusement for you...

and I don't need to change your mind. If you are comfortable with 50k CUP that close to your face and eyes utilizing eyeballed specs to save a few bucks, knock yourself out. Modern metallurgy and machining has spared an awful lot of people that Darwin would have otherwise swept off the chessboard.

You talk about case head separations as if it's an ok thing. I back off when I start seeing primers bulge or extractor swipes. You are wrong about the bolt not closing, depending on the force behind the bolt (and I close mine with authority) and the charge, you jam the lands and force the bullet back into the case when you are short on headspace and light on neck tension. Try that with a fast burning powder near maximum load and there's your hunky-dory case-head separation.

I don't need to see injured people and wrecked receivers on the interwebs to prove what I know. I am an engineer by profession. I don't fool with physics. I control as many variables as I can and using a precision machined tool to set headspace is one of them.

You go do whatever you do...

and unless you know the OP's educational background, skill with tools and generally building anything, the responsible answer is to tell him to use a proper gauge...

All that and you still offer no evidence that using a shim is a recipe for death or even increasing the chances of death. It is simply not true. Everything you stated that you do or can be done has nothing to do with shimming a go gauge. Lets keep this on topic I'm not trying to hurt your feelings brother, there is just no evidence to support your argument. Can you blow a rifle up? Yes. But not using a .004" shim behind a go gauge for a no go.


A known, correct thickness shim on the back of a case head is the exact same thing as a no go gauge. Period.

Paddy has been around long enough to know the scoop. If he doesn't know he asks.

[olddav]

I'm going to interject just to offer my limited experience. Installed a prefit Shilen barrel chambered in 338-06. I used a GO gauge and some scotch tape and yes it is safe (my opinion) as long as you understand its limits. Also I load my own ammo so I can tailor my loads to the chamber in the barrel. I also swapped the barrel on my hunting rifle using the same method and again I load my own ammo for it.
If for what ever reason you do not feel comfortable with using tape and/or prefer using both Go and NoGo gauges then that is what you should do.

[PaddyD]

Ok here's my thoughts. Obviously, after spending big bucks on a barrel I would like to be able to safely install it without the added expense of buying a no go gauge. While I've been wrong plenty of times I think that as long as I screw it snugly to a go gauge I will have minimum head space , which is what I'm going for. When you think about it you can have quite a bit of head space before anything gets dangerous hence the field gauge. Theoretically, as long as I get it snugly onto the go gauge the shimming would really only be required for peace of mind. While it is good practice to use both, the barrel nut system used by Savage make it much less necessary in my opinion. Now if I were to be finish cutting a short chamber on a barrelled action, I would be definitely be using both go and an actual no go to insure I didn't cut to much and create excess space. Hell, I wonder if they even use no go's at the Savage factory. Every Savage I've owned has had minimum headspace and non were even close to no go specs. I know this because the bolt doesn't just fall shut on factory ammo. There's ever so slight resistance when closing which tells me the chamber is tight.
As I mentioned earlier, Yes, I should use both, but given the system Savage uses, my thoughts were of wondering if it were actually "necessary".
I only posed this question because this will be the first barrel swap I have done myself.
Now for my next question, What have any of you used as an expedient method of clamping the barrel without going out and spending more $ on an actual barrel vise? I was thinking of clamping a couple of 2x4 pieces together and then boring a hole between them to use as blocks and then using them in my bench vise. Think that would work?

[DesertDug]

I have used action blocks like you are thinking on AR's it was unsuccessful with the savage action. I use a action wrench and barrel nut wrench. I still am of the use the right tool for a job club.

[olddav]

PaddyD
I built a barrel vise from angle iron and oak blocks and it works well on my first barrel swap. On the second barrel it would not hold. As far as using pine (2x4), I would think that you would be better off using a hard wood for your blocks.

[Texas10]

I use the go gage to set the barrel and after I've torqued the barrel nut, put two pieces of Scotch Tape on the head of the go gage and chamber it. If the bolt closes easily, I go back and re-do it, but frequently the barrel rotates in tighter, not looser when tightening the barrel nut. This is while using the NSS action vice, and barrel nut wrench, not a barrel vice. But I'm something of a tool collector, and would never pass on the opportunity to purchase a good tool that makes the job so much easier, not to mention accurate.

FWIW: I have a Savage FV in 223 straight from the factory that the bolt will close on a no go gage. Headspace measures just a couple of thousandths longer than my Criterion barrel that i set up as per above. Brass life is not any shorter than the custom barrel and I still have my face to look at in the morning while shaving..LOL.

[thaifighter]

I've tried hardwood blocks and it works for installing muzzle devices, but not for barrel installation. the barrel always tends to turn before you get to proper torque. Skip clamping the barrel and use a rear-entry action wrench, barrel nut wrench, and torque wrench...

https://patriotvalleyarms.com/bighorn-remington-savage-action-wrench/




Ok here's my thoughts. Obviously, after spending big bucks on a barrel I would like to be able to safely install it without the added expense of buying a no go gauge. While I've been wrong plenty of times I think that as long as I screw it snugly to a go gauge I will have minimum head space , which is what I'm going for. When you think about it you can have quite a bit of head space before anything gets dangerous hence the field gauge. Theoretically, as long as I get it snugly onto the go gauge the shimming would really only be required for peace of mind. While it is good practice to use both, the barrel nut system used by Savage make it much less necessary in my opinion. Now if I were to be finish cutting a short chamber on a barrelled action, I would be definitely be using both go and an actual no go to insure I didn't cut to much and create excess space. Hell, I wonder if they even use no go's at the Savage factory. Every Savage I've owned has had minimum headspace and non were even close to no go specs. I know this because the bolt doesn't just fall shut on factory ammo. There's ever so slight resistance when closing which tells me the chamber is tight.
As I mentioned earlier, Yes, I should use both, but given the system Savage uses, my thoughts were of wondering if it were actually "necessary".
I only posed this question because this will be the first barrel swap I have done myself.
Now for my next question, What have any of you used as an expedient method of clamping the barrel without going out and spending more $ on an actual barrel vise? I was thinking of clamping a couple of 2x4 pieces together and then boring a hole between them to use as blocks and then using them in my bench vise. Think that would work?

[RCE1]

Having the right tools makes the job pretty simple. That being said, this was not my first barrel change, or even my second or third. I got a NSS action wrench, precision machined nut and recoil lug, short barrel nut wrench and go gauge. I already had a torque wrench. I set my headspace so I can close easily with a little "feel" on the go, but with a piece of .002 tape, cannot close the bolt, which I believe is a more precise chamber than by using a no-go, which is more like .004 -.008" longer, depending on cartridge and manufacturer. Since I NEVER use factory ammunition for anything except rimfire, having a nice tight chamber is one of my goals. The action wrench made it possible to perform the switch without any dings or scratches, which is important to me. I did leave marks on the OEM smooth barrel nut from the pipe wrench I used for disassembly, but it was so poorly made I wasn't worried about sacrificing it.

The tools from NSS are reasonably priced considering the quality and will last for many many barrel swaps.

[celltech]

I won't buy the no-go gauges but I did cough up the money for a barrel vise and it makes things 100X easier. I picked up a Viper but a quick search on Google shows a Bald Eagle vise that is pretty cheap yet looks beefy.