Pietta black powder revolver tested for hardness.

[SomebodyMakeRiderRepro]

Hello,
I obtained few botched pietta screws and a piece of barrel from my local gunsmith for a few bucks.
I always wondered if this big 'black powder only' inscription on the barrel was a liability thing or had some merit to it.
So I had a local machinist test it for hardness.
Here are the results he forwarded to me:
screw: no reading on the RC scale.
barrel: RC 3-5.

I knew the screws were dead soft but the barrel result suprised me. I find the RC 3-5 result worryingly low. Pietta guns always worked for me well regardless.
So here comes my question, has anyone else, ever tested pietta barrel for hardness? If so, what results you guys got? There is always a possibility the machinist botched the test.

Here is the barrel piece that was tested. It is 2021 pietta manufacture as you can see from a dove-tailed front sight.


and a leaf spring screw:


Cheers,
Mike.

 

[hawg]

It's a Uberti. Pietta doesn't dovetail sights. Why are you worried about hardness with black powder?

 

[SomebodyMakeRiderRepro]

It's a Uberti. Pietta doesn't dovetail sights. Why are you worried about hardness with black powder?

Hello, thank you for your quick reply.
It is a pietta 2021 manufacture barrel.
As you can see it lacks a dove-tailed loading lever latch, Uberti should have one. Pietta moved to a dove-tailed front sight somewhere in 2019-2020.

I suspected they use a softer steel but thought more about a 15-20RC range though.

I just find RC 3-5 kinda low for any gun, be it black powder or not. Actually so low that I suspect machinist might have botched the test and would love to hear from anyone else who tested it or had it tested too.

I myself plan on shooting it only the way it was intended - with black powder and in its percussion form but the hardness result might be interesting to people who shoot it with smokeless 45 long colt and a conversion cylinder. I was just curious about steel quality and when got the results just decided to share them.

 

[grter]

How hard were the originals ? I do wonder.

You better believe it's black powder only regardless of what it's true hardness is. It is well known that these are not made with the same quality steel used in smokeless firearms.

 

[SomebodyMakeRiderRepro]

How hard were the originals ?

You better believe it's black powder only regardless of what it's true hardness is.

Sorry, I have no idea how hard originals were but I think they were pretty close to that pietta. RC 3-5 possibly could be in the reach of XIX century metallurgy.

I always thought the main reason for the 'black powder only' inscrption was mainly design where you have weaknesses like the nipple and thin walls in the cylinder and the fact that you can easily load these big chambers with 30-40 grains of smokeless that would possibly blow many modern guns. But for the steel...I believed they used some kind of a gun steel, maybe not heat treated that well.

The machinist says he believes this barrel was made of some common mild steel.

As I stated, I don't plan on shooting anything other than black powder through any of my 'black powder only' guns but given the results I will probably reconsider loading it even possibly too hot too often with strong powders like swiss and heavy bullets like kaido 250 grain.

I mainly share this to get your feedback guys and give some data to consider for guys who handload & shoot smokeless with conversion cylinder.

 

[Cowhide Cliff]

RC35 maybe. 3-5 makes no sense. I haven't tried but I think soft mild steel would read higher than that.

 

[SomebodyMakeRiderRepro]

RC35 maybe. 3-5 makes no sense. I haven't tried but I think soft mild steel would read higher than that.

Most mild steels don't even read on RC scale.

Here is the specification of a common 1018 steel, as you can see it has nominal hardness of 71RB ( 82 RB is 1 RC).


From my experience and the results I can confidently say that the screw was made of unhardened mild steel as it didn't register at all, at the RC scale.

The barrel registered RC 3-5 or RB 84-86. Some mild steels have enough carbon content that they can be hardened to that level.
That being said I can't really tell what the barrel is really made of but modern alloy gun steels have hardness between 22-35RC after hardening.
I suspected the steel used for black powder would be softer as in the range 10-20 RC but not as soft as RC 3-5.

Cheers,
Mike.

 

[Driftwood Johnson]

Howdy

Barrel hardness is irrelevant.

The cylinder is the pressure vessel in any revolver, whether it is a modern revolver or a reproduction of a Cap & Ball revolver.

Back sometime in the 1920s or so, IIRC, Smith and Wesson began heat treating cylinders to improve their tensile strength. As far as I know they never heat treated barrels.

If you want an accurate comparison, test the hardness of a Black Powder cylinder.

Frankly, many of my revolvers, both antique and modern, never see anything but Black Powder cartridges, so I do not concern myself with the hardness of the cylinders.

 

[Cowhide Cliff]

Most mild steels don't even read on RC scale.

Here is the specification of a common 1018 steel, as you can see it has nominal hardness of 71RB ( 82 RB is 1 RC).
View attachment 1039971

From my experience and the results I can confidently say that the screw was made of unhardened mild steel as it didn't register at all, at the RC scale.

The barrel registered RC 3-5 or RB 84-86. Some mild steels have enough carbon content that they can be hardened to that level.
That being said I can't really tell what the barrel is really made of but modern alloy gun steels have hardness between 22-35RC after hardening.
I suspected the steel used for black powder would be softer as in the range 10-20 RC but not as soft as RC 3-5.

Cheers,
Mike.

I would have thought the same thing. Honestly I never bothered checking mild steel. I'm a knifemaker and check my knife blades. They range from 56-62RC depending on the steel and how I temper it. I guess I could check but I assumed even annealed good carbon steel would be more than the 3-5 you are saying those tested. I know it's a more difficult to saw and drill my blade steels than mild steel even when in its annealed state. It may be the other alloys present that cause that. I might check just for the heck of it.

 

[grter]

"The machinist says he believes this barrel was made of some common mild steel."





The machinist is most likely right. That seems to be the common consensus among people who have researched this. I have read it many times in different web articles (sorry no links were saved) concerning the matter.

This type of steel can not be heat treated to any significant hardness from what I read. The best way to harden these type of steels is to color case harden the surface using the best color case hardening process that you can. This is a slow tedious expensive dated but effective process that will only harden the surface. If it's done right it does make a very hard surface though.

Color case hardening is used for both iron as well as mild steel and 19th century steels that do not contain enough carbon in them to heat treat.

For the time and cost of a good color case hardening job I would rather invest the money in a modern heat treated ordinance grade gun steel with a phony (yes it does not look exactly the same) color case coating or no coating at all. Case hardening in high wear parts made sense when mild steel and iron was all that was available but to me not so much in modern times unless one is a purist looking for a close to original clone.

I have read Iron can be pretty hard and does not machine easily but I imagine it's not as strong as steel and will blow to bits and pieces when pushed past it's limits. Using Iron in firearms pressure bearing parts must have been a blacksmithing art to make it just right (with little margin for error ???) Maybe someone who knows can elaborate.

Oh I did once try to use a tiny drill bit on a small press to try to mill (drill and connect the dots) a detent ball slot around the pivot in a CRKT deadbolt lock knife for smoother opening in Krup 4116 steel. No way all I could do was scratch the surface with a high quality drill bit. This is not even the hardest knife steel out there.

In contrast both the Ubertis and Piettas drill like butter and I mean real easy. One old Uberti was extremely hard and tough to drill ( a tiny drill press) but at a certain point the drill bit broke through and man it just glided through about 1/4 inch of the steel (arbor front) like it was the softest thing on earth. I can only attribute this to a well done color cased, or some sort of thin very hard surface coating on the steel.

My conclusions are that tool life, speed, and ease of manufacturing is greatly increased when using mild steel. Because the intended black powder pressures and soft lead projectiles are not strong enough to cause failure or excessive wear manufactures are content with using mild steel. This allows greater profits and lower prices to the consumer.

My understanding is Ruger (Old Army,) Santa Barbara (New Model Army .44) and the Belgium made Centaur brands (Various cap and ball revolvers) Were made to higher quality standards with better steels but people were not willing to pay the extra money and the competitors who at the time used crap steel with lousy fit, finish, and quality control were the ones that outsold the quality ones.

Currently with the introduction of CNS machines lousy fit and finish has been fixed but the lower quality steels (maybe better now but still on the low end of quality) seem to still be used and they apparently do work fine for the purpose (black powder pressures.) It's going to be even harder for high quality guns to compete. The last Ruger Old Army sprint run was over $1000.00 each which is in line with the cost to make in fact even less expensive then the older one made for $350.00 considering how much $350.00 was worth at that time.

 

[TTv2]

It's the bore's hardness that matters and that's the part where work hardening occurs.

 

[Driftwood Johnson]

I have read Iron can be pretty hard and does not machine easily but I imagine it's not as strong as steel and will blow to bits and pieces when pushed past it's limits. Using Iron in firearms pressure bearing parts must have been a blacksmithing art to make it just right (with little margin for error ???) Maybe someone who knows can elaborate.

Howdy Again

Blacksmiths used iron for barrels for rifles and muskets for hundreds of years.Cannon barrels were cast of iron too.

White iron, which is quite pure, is easily machined.

Cast iron, such as a cast iron frying pan, is full of impurities, mostly carbon, which make it brittle. The Bessemer process for making inexpensive steel in large quantities did not exist until 1856. The Bessemer process blew air through molten iron. This burned off the excess carbon. Then a controlled amount of carbon could be added to the molten iron to produce steel. In its simplest form, steel is nothing more than iron with a small amount of carbon added. Other processes for reducing the carbon content of iron existed prior to the Bessemer process, but steel could only be procured in small quantities with these processes.

Colt Single Action Army frames and cylinders were made of malleable iron up until mid 1883. Malleable iron is iron that has been annealed to reform the grain structure so it can be forged without shattering and can withstand the pressure of a cartridge firing. After 1883 Colt began using mid to low carbon steels. In 1900 Colt improved the heat treating process of the steel they were using so Colt revolvers made after 1900 were guaranteed by the factory for Smokeless powder.

Smith and Wesson 1st Model Schofield revolvers had iron frames, made from 1875 until 1877 if I recall correctly.

You are correct about Case Hardening. Case Hardening infuses extra carbon into the surface of iron or steel to produce a thin skin (or case) of harder material. When Colt was first making revolvers, modern heat treatment processes did not exist yet, so Case Hardening the frame produced a wear resistant outer skin on the metal while maintaining the ductility of the inside of the part. Case hardening does not appreciably increase the strength of the part though.

 

[Hasaf]

I had always understood that the reason for shooting pure lead only was the relatively poor quality steel used in reproductions and available historically.

 

[SomebodyMakeRiderRepro]

I understand that Pietta needs to use poor quality, soft steel to keep the price sub 300$ but what I don't understand is why they don't make premium runs of black powder guns made of good quality alloy steel for additional strength and toughness. Guys like me who like to load their guns hot with black powder would appreciate that a lot and pay extra for that.

They pretty much have both the soruce of good steel and technology to process it as they also make smokeless guns. Their premium 900$ "shooters" model asks for a price higher than some branded smokeless guns yet from what I've heard is made from the very same crappy steel they use for their standard revolvers. Extremely expensive 'Pedersoli" Pattern Target revolver is also made from crappy steel.

I've read that Santa Barbara made 1858s were made of good quality, alloy steel and they are something I actively hunt for but they are 50 or so years old and parts are scarce. That pretty much rules out abuse with hot loads as no replacements are readily available.

I know Rugers are just that but I don't like the looks and feel of them. I'd love to have a Remi or Colt made of same quality steel that I could safely abuse with hotter loads.

Sweet dreams.

 

[hawg]

I understand that Pietta needs to use poor quality, soft steel to keep the price sub 300$ but what I don't understand is why they don't make premium runs of black powder guns made of good quality alloy steel for additional strength and toughness. Guys like me who like to load their guns hot with black powder would appreciate that a lot and pay extra for that.

You're not going to hurt a steel frame revolver with bp loads. So load that puppy up and let her rip.

 

[Blackpowderwarrior]

I can only speak for myself here but I've never had issues running top end Sami spec smokeless loads in my guns with conversion cylinders.

My standard black load is 30-35 grains 3F OE in the percussion cylinders or 37-40 grains 3f in 45 colt .

That being said I've often wondered about the steel myself

 

[Driftwood Johnson]

Guys like me who like to load their guns hot with black powder would appreciate that a lot and pay extra for that.

You cannot put enough Black Powder into a modern reproduction to hurt it. Put all the powder you want into the chambers. With a steel frame of course. Don't load too much powder into a C&B revolver with a brass frame. Ask me how I know.

 

[nickshave]

I used case hardening compound on the screws and on the hammer and trigger.I intended to case harden them They all hardened all the way through which surprised me. It must be a high carbon steel just in a totally soft untreated state.

 

[mcb]

HRC 35 would be in the bottom end of the normal range for gun barrels. Even modern rifles rarely exceed the mid HRC 40's. You do not want a gun barrel to be hard 50+. The primary reason is in the case of an over pressure event a hard barrel does a wonderful grenade impersonation creating lots of lethal high velocity fragments. A barrel in the mid 30's to mid 40's if it ruptures in an over pressure event tends to split and peel open creating very few fragments in the process.

Softer barrels are also more tolerant to not propagating micro cracks and other minor flaws into major failures with high cycle counts.

Most modern gun barrels are made from 4140 and similar medium carbon steels and medium carbon stainless steels. The only gun barrels commonly made from mild/low carbon steel trends to be 22LR and in those cases hardness can be down into the twenties.

 

[SomebodyMakeRiderRepro]

HRC 35 would be in the bottom end of the normal range for gun barrels. Even modern rifles rarely exceed the mid HRC 40's. You do not want a gun barrel to be hard 50+. The primary reason is in the case of an over pressure event a hard barrel does a wonderful grenade impersonation creating lots of lethal high velocity fragments. A barrel in the mid 30's to mid 40's if it ruptures in an over pressure event tends to split and peel open creating very few fragments in there process.

Softer barrels are also more tolerant to not propagating micro cracks and other minor flaws into major failures with high cycle counts.

Most modern gun barrels are made from 4140 and similar medium carbon steels and medium carbon stainless steels. The only gun barrels commonly made from mild/low carbon steel trends to be 22LR and in those cases hardness can be down into the twenties.

I double checked my conversation with the guy who tested it for me and he clearly said RC 3-5. I was as surprised as you are. I expected at least 20 HRC for black powder though.

 

[SomebodyMakeRiderRepro]

You cannot put enough Black Powder into a modern reproduction to hurt it. Put all the powder you want into the chambers. With a steel frame of course. Don't load too much powder into a C&B revolver with a brass frame. Ask me how I know.

Using 3F, 100% agree.
I am a bit worried about FFFFg though. At some point I'd like to try it but I have my worries. Especially with THAT soft steel...

I myself go with 34 grains FFFg and a 220 grain bullet... Which you can see here for results:


However, I am not so sure if a hefty charge of FFFFg would be safe though and it is something I'd like to test at some point...
Now I wonder, if a stainless cylinder would be a tad more tough. Stainless steels generally have a somehow better tensile strength than mild steels which I believe were used to build my current two blued piettas.

 

[SomebodyMakeRiderRepro]

I used case hardening compound on the screws and on the hammer and trigger.I intended to case harden them They all hardened all the way through which surprised me. It must be a high carbon steel just in a totally soft untreated state.

I m pretty sure hammers and triggers are made of a very different steel. Possibly the same type they use for their smokeless guns. These parts must be hard because otherwise they can wear quickly and risk accidental discharge.

 

[Driftwood Johnson]

Why in the world do you want to use FFFFg?

FFFFg is for the pan of a flintlock rifle. That's all FFFFg should be used for.

I m pretty sure hammers and triggers are made of a very different steel. Possibly the same type they use for their smokeless guns. These parts must be hard because otherwise they can wear quickly and risk accidental discharge.

Years ago a gunsmith told me that the internal parts such as the trigger or hammer do have some Case Hardening. Perhaps a simple chemical treatment rather than true bone case hardening. He told me that in fitting a part, the outer surface was quite tough, until he filed enough to cut through the case hardening to the softer steel underneath.

 

[mcb]

I double checked my conversation with the guy who tested it for me and he clearly said RC 3-5. I was as surprised as you are. I expected at least 20 HRC for black powder though.

That seems really soft for a gun barrel. As in annealed low carbon steel. That said my experience is with modern current production smokeless firearms. For a black powder reproduction that might be sufficient but it's also not that much harder or costly to get into the 30's pretty easy.

Why in the world do you want to use FFFFg?

FFFFg is for the pan of a flintlock rifle. That's all FFFFg should be used for.





Years ago a gunsmith told me that the internal parts such as the trigger or hammer do have some Case Hardening. Perhaps a simple chemical treatment rather than true bone case hardening. He told me that in fitting a part, the outer surface was quite tough, until he filed enough to cut through the case hardening to the softer steel underneath.

Many are cast from low carbon steel (8620 is common especially AR fire controls) and then case hardened. The carburization is formed in high carbon atmosphere furnace rather than getting the carbon from bone char. Modern case hardening penetrates more and will typically be .008 -.012 deep into the part. It's also very hard on the surface 58+ but still soft in the core.

 

[hawg]

I don't understand why people want a bp gun to perform like a modern one. 30 grains of FF and a round ball is plenty good enough for me.