Conversion Cylinders ... Safe?

[Dino.]

I know you're only suppose to use "cowboy loads" in guns that have been converted with conversion cylinders from companies like R&D ...
But what about guns that are bought with the conversion cylinders, like the Richards-Mason? Is it safe to shoot modern loads out of these guns ... specifically .38sp?

[Onward Allusion]

I think most if not all conversion cylinder manufacturers will state that you should only shoot black powder cartridges out of them. When in doubt, call the mfr. Also, 38s are prone to tumbling/keyholing out of these revolvers.

[PetahW]

I would be much more concerned about the frames the conversion cylinders were fitted to, than the cylinders themselves.

The Ruger Old Army (ROA) uses the same frame as their centerfire revolvers - not so with many replica types, and doubly so with brass-framed guns.

A revolver with a top strap is inherently stronger than any open top, but the steel used in many replicas isn't as strong as the steel used for centerfire revolvers.

.

[mykeal]

A revolver with a top strap is inherently stronger than any open top

I'd have to disagree with that. Can you show me the loads and stress analysis that would prove it?

[sundance44s]

Just do a google search ..you can read all day why the Opentop is a weaker design than the top strap models like the Remingtons .
Some would still argue with a stump though ...

[Dino.]

Well, I know that these conversions aren't recommended for guns with brass frames.
But what about todays (steel frame) replica conversion pistols that currently come this way from the factory?
Though they are based on the original designs, I would think by todays standards, the material used would/should be good enough to withstand modern cartridges.

btw ... are the barrels on these modern replicas rifled?
Just curious.

[robhof]

If it's a b/p replica, even with a factory conversion; they aren't safe with modern high pressure rounds. Even the ROA uses cowboy loads in their conversion. All revolvers are rifled, single shots and Howdah's are a mixed batch.

[hickstick_10]

I'd have to disagree with that. Can you show me the loads and stress analysis that would prove it?

why do you disagree?

[Dino.]

Well, this is one of the conversion pistols I was looking at ...
http://www.gunbroker.com/Auction/Vie...Item=158793937

I emailed the seller and asked if it would handle modern loads and he replied that it would.

I also looked online and downloaded the owners manual and nowhere in there does it say that it will or will not handle modern loads.

I guess I need to write the manufacture.

[Wobble]

Here's a quote from the paper that came with the .45 R&D cylinder for my 1858 Remington:

".45 Long Colt "Cowboy Ammunition" is nationally available from a number of well known manufacturers. This ammunition is loaded for a maximum muzzle velocity of 750 to 850fps, and these are the specifications we recommend."

"Use of ammunition other than factory loaded "Cowboy Ammunition" by reputable manufacturers or black powder, black powder replicas voids any warranty ..... "

The warnings are there as a result of the relatively thin walls in the cylinders in order to cram in six chambers. Although I don't have one of the conversion guns, my guess is that the frame hasn't been enlarged to accommodate a larger cylinder with thicker cylinder walls. Therefore, cowboy ammo should be used.

[Gaucho Gringo]

From what I have read on the dealers and manufactures websites this gun is perfectly safe to shoot with normal .38 Special smokeless ammo. +P is a big no no in this gun but regular .38 Special smokeless would be fine.

[Fingers McGee]

But what about guns that are bought with the conversion cylinders, like the Richards-Mason? Is it safe to shoot modern loads out of these guns ... specifically .38sp?

To answer the question asked. An opentop, Richards, Richards -Mason, type II Richards, and Man With No Name Conversion cartridge revolvers in 38 special/38 colt are safe to use with standard velocity 38 special smokeless loads. Same goes for .44 special/colt. There have been reports of the .45 cal conversions exhibiting cracking of barrels where the arbor relief is milled into the forcing cone with standard loads.

Retrofitting a percussion revolver with a cartridge conversion cylinder is another matter altogether. Only Cowboy loads are recommended for these.

[Dino.]

To answer the question asked. An opentop, Richards, Richards -Mason, type II Richards, and Man With No Name Conversion cartridge revolvers in 38 special/38 colt are safe to use with standard velocity 38 special smokeless loads. Same goes for .44 special/colt. There have been reports of the .45 cal conversions exhibiting cracking of barrels where the arbor relief is milled into the forcing cone with standard loads.

Retrofitting a percussion revolver with a cartridge conversion cylinder is another matter altogether. Only Cowboy loads are recommended for these.

Makes perfect sense, thanks.

[madcratebuilder]

Just do a google search ..you can read all day why the Opentop is a weaker design than the top strap models like the Remingtons .
Some would still argue with a stump though ...

Just because it's on the net does not make it a fact, it's urban myth.

[mykeal]

Originally Posted by sundance44s

Just do a google search ..you can read all day why the Opentop is a weaker design than the top strap models like the Remingtons .
Some would still argue with a stump though .

I've done the Google search; all you get in favor of the 'Remington is stronger' argument are opinions based on the fact that the top of the barrel assembly is attached to the frame - no (correct) free body diagrams, no loads analysis, no stress analysis, just urban legends. Some even claim that it must be true because the government required Colt to change their design! Now there's a compelling argument: the government said so! I do have to agree, however, that those who still expouse this urban legend do closely resemble stumps, so perhaps you're right about that.

Originally Posted by hickstick10

why do you disagree?

Because I've done the free body diagrams and can see how the loads are distributed.

I did not intend to hijack the thread; I only wanted to disagree with one of PetahW's statements. Every time someone makes that claim and it goes unchallenged the myth tends to grow, so I just wanted to make it clear that not everyone believes it. The subject has been debated at length (as Google will attest), so let's just let this thread go back to it's original thesis, with my apologies for stating a truth and thus derailing it.

[sundance44s]

Hey don`t get me wrong Mykeal ...I love my Open top Colts they are by far the best pointing and sexyest looking revolvers by far .
The 1860 Colt feels like a long lost friend in my paws .
But in the real world ...I have also had more problems out of them as far as wear .
My Remingtons only got better with wear ......
Its a simple test ...buy both ..shoot often and it won`t take long to see which is stronger built .
Not good to beleive what ya read anyway ...it has only assisted me in dealing with the problems one might incounter with eaither model ..and I`ve had to work on my Remingtons much less .
doing a little rescearch and reading on the forums has kept me from buying a Colt Patterson ...and some will say' buy it you`ll like it '

[hickstick_10]

Because I've done the free body diagrams and can see how the loads are distributed.

I did not intend to hijack the thread; I only wanted to disagree with one of PetahW's statements. Every time someone makes that claim and it goes unchallenged the myth tends to grow, so I just wanted to make it clear that not everyone believes it. The subject has been debated at length (as Google will attest), so let's just let this thread go back to it's original thesis, with my apologies for stating a truth and thus derailing it.

If you could post these free body diagrams I would be very grateful, Im an engineering student and it would be very neat to see how you worked out the forces on the open top.

Id agree in some ways that open top is equal to the remington in cylinder strength and back thrust but Im curious as to how its stronger with the pressure working on the face of the barrel and the cylinder creating a moment about the axle, and its only counteracted by the shear strength of a little steel wedge. Compared to the solid steel supports of the remington.

pm me if you wish

[Hardcase]

Hickstick, I'm just thinking this in my head, so it's hardly an engineering proof, but bear with me.

Looking at the revolver, it seems to me that the force exerted on the wedge is more linear than axial, although since the wedge is below the barrel and the barrel assembly to arbor fit isn't perfect, there will be some axial force.

The force that is transmitted down the barrel from the exiting ball and gasses certainly act upon the wedge, but the axis for the torque that is generated is the shooter's wrist far more than the wedge.

Now, there is also the question of the barrel to arbor fit, since a loose fit could cause the barrel assembly to pivot about the barrel/frame interface which would, over time, cause wear in the wedge area. On my revolver, the arbor fits the barrel pretty well and the arbor itself is pretty doggone massive (relatively speaking).

The weak link, it seems to me, is not the wedge, but, rather, the person holding the gun. The force down the barrel is linear. The force on the shooter is axial about the wrist. Now, if the revolver was held in a rigid frame, then I think things would be different and you would start seeing accelerated wear in areas like the wedge and maybe the base of the arbor - the forces acting on the gun would be different.

It's also possible that I'm completely out to lunch. This is why they keep us electrical engineers across the hallway from the mechanical engineers.

[hickstick_10]

Hey Im just a student and I was a machinist before so i know a tad more about making guns then i do about the forces generated (which amounts to almost none)

My thoughts on this are there is a force generated between the face of the cylinder and the forcing cone face of the barrel.

You know how you have to bolt steam pipes together right? Well see pressure of the steam x cross sectional area of the pipe would create a thrust, that is overcome bolted connection of the flanges.

In the revolvers case you have 2 bores with roughly the same cross sectional area, along with a pressure generated by the explosion, and the only thing that is overcoming the thrust caused by the explosion is the shear strength of that little retaining wedge.

But like i says, im just a student, and I shoot a stainless Ruger Old Army so what I know about open tops amounts to knee high in jack [color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color].

[Hardcase]

OK, I see what you're saying. Yes, for sure the wedge is under stress from the impact of the ball on the forcing cone, but remember, that collision between the ball and forcing cone is elastic. I'm just guessing here, but my guess is that the result of that impact is that the vast majority of the energy will be dissipated in the deformation of the ball as it "squishes" (technical term, right?) into the lands and grooves of the barrel.

I'm not a metallurgist, so all I know about steel is that it's hard. But my assumption is that as long as the wedge is a solid, tight fit, with no movement between it, the barrel and the arbor, as long as it's made out of the proper steel, it should not be a failure point.

I would expect the cylinder walls to fail before the wedge fails - the force, specifically the impulse at ignition, acting on the cylinder has to be a whole lot greater than that on any other part of the gun.

And as a student and machinist, you're a whole lot closer to the physics behind this stuff than a 50 year old electrical engineer! I can't plug it in, so it's all a mystery to me!

[hickstick_10]

its not the impact of the ball im getting at. its the pressure BEHIND the ball, if there wasn't a few thousand psi behind the ball, it would never leave the barrel. And this creates a pressurized connection between the cylinder face and the barrel breech, like 2 steam pipes butted/joined together which when you take pressure multiplied by cross sectional area of the bore, gives you the force which is trying to push the barrel away from the cylinder.In the pressure behind the ball idea I would have thought the Remington would win hands down

So many firings, puts so many cyclic loads on the wedge, I'd rather rather have a solid frame of steel with a threaded barrel taking the loads, then glorified piece of sheet steel. The open tops win the looks category hands down though, I think the Remington style is damned hideous.

But like I said, im just a student, il keep tinkering with the free body diagram, at least until it points that im FOS (when im not swamped with godamned homework):barf:

[Dino.]

Okay, I emailed Cimarron Sales (Chiappa) and asked ...

"Can you please tell me if the 1872 "Open Top" pistols are built to handle modern loads? Or are they restricted to "cowboy loads" only?"

Their response ...

"They are made to take standard factory ammunition, not just cowboy loads, but not plus p either."

[Ben Towe]

A box is stronger than a U. There's your answer. I'll agree an open top is more pleasing to the eye though.

[Dino.]

A box is stronger than a U. There's your answer. I'll agree an open top is more pleasing to the eye though.

I would think this has more to do with the walls of the cylinder as opposed to the construction of the frame.

If the cylinder can't handle the load, it doesn't much matter how the frame is constructed, does it?

[w_houle]

Meh, I just shot whatever was commercially available through my R&D.. Usually this
https://www.budsgunshop.com/catalog/...ducts_id/66102
The only problem I have with .45 Colt is it has a standard OAL of 1.6" and the cylinder likes them at 1.58". So I usually spent the time waiting on those I go to the range with filing bullet noses down to make them fit.