3D Printing Headspace Gauges

I’ve been looking for headspace gauges, and they were all out of stock, or stupid expensive, so I figured, why not print my own?

I’m only doing this for rimmed ammo, so I figured 3D printing them with plastic shouldn’t be too hard, as the rim thickness is the important part.

The only problem I can think of right now is that if the rim is thin enough, the plastic could potentially get crushed. I’m thinking that this could maybe be solved by printing in a certain orientation to take advantage of the anisotropic properties of printed material.

Is there something I haven’t considered, or is this actually something viable?

I don’t think “anisotropic” is a real word, other than that I can’t really see a problem with it.

It’s considering the orientation of the material. Like how you want to be with the grain when woodworking.

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I know very little about 3D printing but I don’t know if the tolerances on a consumer 3D printer would be tight enough to get you as accurate a gauge as you would need. I’d also be worried about any sort of flex in the plastic. This may be nothing to worry about at all but just something to consider.

Yeah, I thought about that. I’m using a friend’s printing which prints PLA. He claims that the margin of error is 0.1 mm.

I figured that if I need to, I can print the rims a little thicker, and use some fine sandpaper to remove material as needed. I’ve got some okay calipers at home, so I could confirm the thickness before I use them.

Honestly, Head spacing concerns are far out of proportion. Modern brass will easily stretch to all but the worst of head spacing issues. I don’t even check anymore. Never had an issue. The cost and fkery involved in ‘fixing’ any issues is often a road to nowhere. Use modern brass, enjoy your rifle.

If it’s well tuned, tolerances shouldn’t be an issue. PLA however might be. I’d give it a go, but print at 100% to avoid flexing and compressing.

…but I am with @Supaduke here. Load lite, send a few and you will know. I never checked. Well, I did check, but in a more orthodox, put the safety glasses on and cover your nads kind of way.

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For rimmed ammo you can use the quick method of apply layers of scotch tape to the head of the case until the bolt doesn’t close, measure the rim thickness plus the thickness of layers of scotch tape to determine your headspace measurement. Best done with extractor and ejector removed from bolt.

So I tried printing one today, specifically a Field Gauge of 0.074 in.

It’s come out to be 0.082 in. Not ideal, but I think I can file off the excess to make it the required value. I’ve tried this gauge anyway, as I’ve read that wartime emergency allowed for a maximum of 0.084 in for stockpiled rifles.


I think it works though as a proof of concept. It’s definitely stopping the bolt from closing all the way, and it’s rigid enough that I don’t think there’s any flex.

Looking at the plastic after trying to close it a couple times, I can’t see any wear or damage on the plastic. I took measurements after using it, and it was still 0.082 in.


I’ve already started printing more to file down for a complete set of gauges, and it’s estimated the plastic will cost me around $10 for all of it, compared to the $180 Brownells Australia was asking for all three.


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Good stuff mate.

I wonder could you make one out of a softer plastic that was oversized, crush it with the bolt and then measure it. Sort of a single use gauge.

It’s decent idea, but I think it provides it’s own challenges.

Theoretically, this would work if you fully plastically deformed the material, but the problem is that if you don’t fully crush it, you’ll have some elastic recovery; about 2% for PLA if I’ve read the stress-strain curve right.

Usually not a big deal, but this is a recovery of a couple thousandth inch, so maybe not ideal for headspacing.

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Yeah just a thought that popped into my head reading your other post, I admit that 3D printing is Swahili to me.

Got the remaining prints done, and filed, it worked really well.

Field Gauge

Go Gauge

If anyone wants some, I’m happy to print more or provide the .stl file if you’ve got a printer.

Time to make some Mosin gauges lol.


I love watching folks with an idea, make and refine stuff. I was starting to think it was another lost art, keep it up mate… Works out or not is irrelevant, experimenting and giving it a good old crack is bloody gold. It’s amazing what you can learn along the way… :+1:t2: :sunglasses: :beers:

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