Mosin-Nagant Factory Pressure Test Rifle

"Why is there a thing growing on my mosin"
-Unknown boy, aged 10

This is very cool, thank you

The cone on the end of the thread is also the sealing surface, to stop gas leaking up the threads.

A really interesting video, thanks for sharing the CUP process

I want to see this tested bad

That's so cool.

This is actually kind of simplistically genius, I wouldnt have thought to measure it in such a crude way, but measuring the deformation there would be mathematically super easy

This is so cool! It’s basically a second year engineering strengths problem to test a useful application!

a crossover item for collectors of scientific instuments and gun enthusiasts

Is that device cracked? It looks like a hairline crack at the corner.

What I learned to reload with was old lyman manuals and they all used cup whats weird is 45/70 gov is 24k cup and 24k psi may be only place they match cool to see the rifle and tool that those tables were made with

It is also not surprising that a working gun factory during an active war would not have hundreds of half finished guns just lying around, as whatever they could deliver would go directly to whatever Front there still was... Sure SOME pieces would be in assembly, but if you're hammered down upon you usually have no time to buidl giant stockpiles of premade components without immediately completing shootable guns. Thus prototypes and such test guns would be some of the few weapons you actually could find completed in such a place.


You also forgot that the Soviet Union was in a LOT of wars between 1918 and 1940 ... Finland with Winter War and Continuation war, the Civil War and the accompanying last campaigns against the Whites and "Blacks" (with the Soviets themselves aka Bolsheviks being "the Reds") including an American & allied Invasion in Karelia and the far East around Vladivostok that lasted most of 2 years!, the Caucasus and Balkans, twice against Poland, once against Ukraine... If a gun went through all possible service from 1916 to 1945 it has seen a LOT of action in a lot of far apart places!

M16 makes neat wounds. Complies With The Geneva Convention. AK-47 makes terrible injuries. Does not comply with the Geneva Convention. The Mosin rifle is the reason for the creation of the Geneva Convention

CUP doesn't take Overall Time of Active Pressure into account, since theres no measure of duration. In contrast to SAAMI PSI piezo-test, which can measure duration and blast pressures, CUP is like using a Ballistic Pendulum instead of a Chronograph.

Soooooooo, how much did it sell for?

Beautiful rifle.

I don't understand exactly why this wouldn't translate to PSI. Is it because the same pressure (measured in PSI) applied to this exact same device in two different guns, yields different amounts of "copper smashing?" Or some variable they couldn't control causing different deformation using the same pressure?

Anybody know what this sold for?

Can we see this on a 50 cal

I saw a 1916 Spanish Mauser pressure test rifle for auction once. I should have bought it.

the whole rifle is a test pressure system, very interesting

Ha ian said c u p

No test fire ? No result compressed copper ? We'd like to see it in action and the result !

На буржуйском ресурсе инфа о нашей винтовке гораздо интересней

Aaaah yes the Russian made bean injector

Anyone know how much this sold for?

Need to email Ian some pics of my 1918 303 british

The lettering on the rifle: "Imperial (royal) Tula's (town name) gun works" so it was a state owned gun factory.

Damn, I thought he was going to demonstrate it or at least show a before and after picture of the copper plugs.

C U P


Hehehehehe

I'd read about crush gauges before, but until I looked closely at the thumbnail, I'd never seen one before. Don't think I've ever clicked faster than when I realized what I was looking at.

I always wondered what that meant. Thanks Ian.

You ought to be able to convert it over. You would need a stress/strain curve for compressive strength (most of the available graphs are for tension) but then it should be feasible to convert over to psi.

What I don't understand is why the steel band going across the breech doesn't blow out ?

Also, this provided the perfect sight picture for blind people! A sight picure that's completely METAL, one might say :)

very interesting part of gun history

They saddle taped it!

CUP v PSI is like Brix v percentage solids in food processing. It means something consistently, but conversion to other units is futile.

Today felt like 6 cooper pressure units in the air

So...this is different with proofing, isn't it?

Wait.......what.......ya didn’t shoot it and show us the before and after measurements. 🤬🤬

A fascinating engineering application of using a measured axial deformation of a member with known properties! I imagine these must be relatively accurate at measuring chamber pressure.

Copper Crushers, as the copper pistons are know were a common way of measuring the in chamber pressure of many rifles. Normally what would happen would that a manufacturer of these 'crusher's' (which came in rods and balls) would sell them as lots with pressure tables (a tarage table), as Ian mentioned, one you have fired your round you would measure the amount of compression on the rod and ball and compare it to your table to give you a pressure measurement. This system had been around since the early 50's and was uses world wide in small arms, even though it began life which large calibre (i.e. artillery pieces).
As of 1977 Abderdeen Test Centre delcared that the Copper Crusher Method was no longer suitable for NATO purposes as it could not be measured precisely, therefore nowadays most NATO countries (and many non NATO countries), use Piezoeletric sensors which are quartz based sensors which can provide measurements with accuracy to normally 0.5%. (Depending on how well the equipment has been maintained, whether it is within it's calibration spec and the DAQ system it is attached too is operated by a competent user).
Oddly enough you still see copper crushers being used in and around the middle east and normally on shotgun cartridge testing mainly out of habit and that Piezoelectric sensors can be expensive (read approx $2-3k per sensor).

But seriously wht tf copper and not led oder brass??

Seems very safe lol

So this is why all men are enchanted by CUP size?

Gorgeous looking piece and very neat example of early rifle testing.

"...and then this guy sits right in there..."
Not gun Jesus, that's probably Browning, Stoner, Kalashnikov, or another gun smith.
Ian is Gun Bob Ross

Would there be case wall covering the hole at the base of the chamber? I mean, if the case strength is also accounted for in this method, and the cylinder is measurably squished, the case would be ruptured or noticeably deformed, right?