Early trials with a Snider

[afmelo]

Yes, the numbers for that powder also look good but as the speed of the powder goes up, so does the potential for small errors in loading and small increases of powder causing geometric, thus unexpected spikes in pressure. Both N110 and N105 are in the burn speed zone that may work in the Snider. One thing I do when looking at this type data is to construct a simple pressure curve. Then at the point of interest of the intercept between charge and pressure on the curve, draw a tangent line at that point. The slope of the tangent line at that point instantly gives an intuitive, visual feedback of the geometric relationship between the charge and pressure. IMO and in my thought process, the steeper that slope, the greater the potential for an "unplanned" excursion into a zone of extreme pressure.

Another thing that may play a role in powder suitability for any particular application is the chemical nature the powder. I think generally, no matter the burn speed, double base powders inherently carry greater stored chemical energy than single base powders.

Pic is of a chart by Vihtavuori showing relative burn speeds of various powders. More data is always better. This copy is dog-eared for a reason

View attachment 535525

Yes, single and double base powders really have a different behavior - I use a lot N140 and N540 in my 6Norma BR benchrest loads. They are very different in reaction to weather conditions, namely heat and humidity. After a few years I prefer single base powders - more stability and less barrel heating!

I assume the same should happen with these old guns loads, although my experience is limited here.

I have been learning a lot with you on the Snider. But my most recent "baby" is a Westley Richards monkey tail... One of 8.000 carbines ordered by Portugal in 1866, delivered in 1867. It is in superb shape and ready to dance... But in this last case nobody seems to risk a smokeless load! In your opinion is there a way to use a lite load of smokeless in this gun?

 

[Tubby’s Canteen]

Interesting thread! I’d like to get a Snider sometime soon. I’m only a few minutes outside of Halifax, so if I can I’d like to get one like yours from the Halifax garrison.

A fellow bluenoser!!

 

[fourfive8]

Yes, single and double base powders really have a different behavior - I use a lot N140 and N540 in my 6Norma BR benchrest loads. They are very different in reaction to weather conditions, namely heat and humidity. After a few years I prefer single base powders - more stability and less barrel heating!

I assume the same should happen with these old guns loads, although my experience is limited here.

I have been learning a lot with you on the Snider. But my most recent "baby" is a Westley Richards monkey tail... One of 8.000 carbines ordered by Portugal in 1866, delivered in 1867. It is in superb shape and ready to dance... But in this last case nobody seems to risk a smokeless load! In your opinion is there a way to use a lite load of smokeless in this gun?

I just glanced through the 2020 thread on the British Forum and didn't see nor search very hard for current load data- but it may be there. The 2020 thread on the Monkey Tail looks like they were putting together a design for a mould by LEM.

IMO, The Monkey Tail falls into the same category as all such transition designs between the muzzleloading musket and the breechloading cartridge rifle. It is similar to but not the same as other such designs. Seems like a combination of unique parallel engineering features similar to the trapdoor, paper cartridge Sharps carbine, Snider and even the Maynard... It utilizes a breeching seal system instead of a metallic cartridge.

I would still classify the WR version as a musket conversion even though the WR is described as the latest and best of the various iterations of the Monkey Tail. I don't know the metallurgy in the construction but assume the early ones were iron, the same as the muskets. The later model by WR is still from the 1860s so have to assume it's also iron... to error on the safe side. If using a conical, I think something in the 400gr range would be proper in the carbine. Also a roundball of approximate groove diameter up to .002" larger than groove diameter may also work. I would recommend black powder and not smokeless. I've never shot nor inspected one closely so really can't say much about its overall design strength. Interesting project and looking forward to reports on progress!

 

[fourfive8]

@afmelo
Also, another consideration for loading/shooting this type arm, IMO, is the gas seal. Could be that the chamber and the breech block are fully capable of handling a MAP of 10k psi or so but the “weak link” may be the design of the gas seal. ?? Wish I could be of more help

Here’s something to study for consideration when crossing over into smokeless loads in firearms originally designed for BP. The reason I always approach this with extreme caution.

 

[gizmo]

@gizmo, Here's the crude little cutoff tool I made for trimming the 24 ga brass. Seems to work and makes consistent, clean cuts without damage to thin case walls
pic series for basic tool and procedure

before and after lengths, I cut my Snider brass to 1.98"
labeled "tool" with Dremel clamped and stationary ready for cutting
close up just at beginning of trim
close up just after trim
Shallow U shaped vee with stop to hold case during cut

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Thank you. That is a great idea

 

[afmelo]

@afmelo
Also, another consideration for loading/shooting this type arm, IMO, is the gas seal. Could be that the chamber and the breech block are fully capable of handling a MAP of 10k psi or so but the “weak link” may be the design of the gas seal. ?? Wish I could be of more help

Here’s something to study for consideration when crossing over into smokeless loads in firearms originally designed for BP. The reason I always approach this with extreme caution.

View attachment 535564

Many thanks for the prudent advice on the WR... Point taken!

I was impressed with your graphic - will look closer to the pressure building timing for the future and compare the various similar loads on such particular point.

 

[fourfive8]

As a non-scientific aside. After shooting so many rounds of experimental black powder ammo out of the Snider the past few years, the four smokeless shots the other day re-enforced that feeling of- "use caution". No smoke, no low frequency booooom report, no big recoil push... all so common and recognizable with black powder loads. BUT with the smokeless loads, the unmistakable "crack" sound of a large bullet that is sonic and the fast acceleration of the recoil impulse even though it was very mild- are both reminders of what is going on with the smokeless load vs a black powder load. Try to visualize and correlate the shape of the pressure curve during the firing process to the sound and feel of the shot.

A long time ago I did some destructive testing on a handful of firearms. And recorded the results with a high speed camera. It was done for production of safety and training material.... during a previous life. The testing was outdoors, using large dirt berms for isolation of the tests. I was surprised by the sound of tests. I had expected a big "booooom" sound. Actually the sound of a grossly overloaded firearm structurally failing is more of a muffled high frequency "crack". I later concluded the "crack" was diagnostic of both the escaping gas and pieces of the firearm being sonic.

 

[fourfive8]

@almelo
Here's some background and basic load info for the Snider as found in the reference: Cartridges of the World, 8th Ed. Here too, I would approach this data with caution. The editor of this edition is a friend of mine but I do not believe he did the testing of the 577 Snider for this publication. Being the editor, he is the chief proof reader and checks for accuracy of the data and the reliability of the sources of the data. That assurance helps but does not take the place of the reloader's own due diligence.

Can't have too much data COTW is a very handy reference to have in the library.

 

[afmelo]

I have the 13th edition, same loads!
Also, although restricted to 30gr of 4198, in "The Handloader's Manual of Cartridge Conversions", one of my mail tools for old guns...

​

 

[afmelo]

I have the 13th edition, same loads!
Also, although restricted to 30gr of 4198, in "The Handloader's Manual of Cartridge Conversions", one of my main tools for old guns...

​

Here photos of the HMCC and Snider cartridge page. Notice that the proposed donor cartridge to convert to Snider .577 was the .577 NE (BELL) - an expensive rarity nowadays!

 

[afmelo]

These are the bullets I have ready available here, made by ARES, a company from Slovakia (https://www.ares-gun.sk/perkusne-ares.html ) . They produce lubricated lead bullets and powder coated. I am trying the powder coated for the time being for as long as I do not have an appropriate bullet mold.
This is a minie .575 weighting 510gr.

 

[fourfive8]

That Minie' needs a name!- either "The Incredible Hulk" or the "Green Hornet"

Seriously, it looks like a classic, old design Minie'. It will be intersting to see how it does out of a Snider. It was designed for a slow twist musket. I shoot quite a few Minies' out of original muskets loaded with BP. How the base reacts to smokeless will also be interesting. If the charge doesn't blow out the skirt and it gets a good, straight start out the muzzle, it should do fine. Minies' depend on two types of stabilization functioning in concert during flight- gyroscopic and aerodynamic. And when they are ballistically happy, they can be surprisingly accurate.

I've generally had the best luck using black powder in both rifle muskets and the Snider with a Minie' that some call the Hodgdon N-S or RCBS N-S This one is pre-lubed. The only thing I noticed in the Snider was an occasional flier with this Minie". I never could figure out the cause ??

 

[fourfive8]

577 Bell... thank goodness for the 24 ga Magtech!

 

[afmelo]

Found a software for black powder calculation. Input Snider data for your 520gr bullet and 70 gr black powder.
Here is the result!
Noticed that the pressure curve is faster growing than with your test with 30gr of 5744 !

 

[afmelo]

The site for the BP calculations is:

P-Max black powder internal ballistics

 

[fourfive8]

Hmmm? Something is not right. I looked at some published pressure data recorded from firing tests of transducer mounted guns. It shows peak pressures of approximately 4800 psi in a 58 caliber 530 gr Minie load with 70 gr black powder. I don’t see 10k+psi pressures in any BP test data until the powder stack height gets sizable per caliber under standard weight/design bullets. So it seems odd the predictive program to show approx 10.4k psi peak pressure with the relatively short stack height of a normal service load load of 70-73gr BP under a normal style bullet of 520 gr in 58 caliber.

 

[afmelo]

Many thanks, I was surprised as well!
Found this. Do you know?

Internal Ballistics

observations on modern Internal Ballistics software

kwk.us

 

[afmelo]

As previously mentioned, I am by no means educated on BP rifle loads! I am just starting with older BP rifles and trying to learn as much as possible. This is why I am abusing your knowledge, trying to understand the main differences of the game!
Being a competition benchrest shooter where we try to extract the maximum “juice” from our preferred powders that still accurately hit the target where we “dream”, this black powder game seems to be very different!
The Snider and Westley Richards monkey tail are my current BP projects.
But I have used smokeless in my 8mm Steyr Kropatshchek from 1886, (a couple of years later the army factories adopting officially smokeless without any issues). Evidently the construction with excellent steel of these rifles cannot be compared with the iron barrels of the converted Sniders!
But my curiosity was driving me to investigate whether we could compute the pressure curves of either powders, to understand where the problem stands.
For modern powders I have QuickLoad, which seems to be excellent and predicts my chamber pressure and bullet velocity within very close differences to the actual measurement with LabRadar.
As soon as possible I will measure the Snider speed as well, using your receipt of BP behind that green bullet that called your humoristic reply!
But, at the end of the day, what I mean is that I do apologize if my constant questions and research for answers is in any way a burden for you, wasting your patience!

 

[fourfive8]

I guess the way to look at it is realizing BP and smokeless are completely different in burn characteristics. BP is very forgiving because of the nature of its low efficiency. Contrasted with progressive smokeless which by comparison is very efficient. That efficiency and stored chemical energy can easily and quickly run past predicted pressure and get into the zone of dangerous pressure in the closed, expandable cell of a firearm's chamber and bore.

Here's is a hypothetical pressure versus powder charge curve showing that relationship and the idea of the slope of tangent lines at intercept points to visualize the potential for geometric increase in pressure for linear increase in charge, especially apparent when comparing smokeless to BP. The slope becomes very steep very quickly with smokeless pressure curves relative to BP curves. At some point in most chamber pressure curves very small increases in smokeless powder charges can mean huge, unpredictable increases in pressure. BP burn, conversely, is inefficient and only slightly progressive so run-away pressures are much smaller, more predictable and less likely to reach firearm failure limits because of small errors in charge amounts.

 

[fourfive8]

That critique of ballistic modeling software programs seems fairly complete and well written. Thanks for sharing! It seems to confirm my thoughts on the subject- use them with caution and understand the limitations of predictive software.

As another aside, the one modeling software I use a lot is the trajectory program by JBM Ballistics. I use it in conjunction with my own chronograph results. I’ve found it to be very accurate if good input data is used. Again, it has limitations and requires an understanding of those including the BC estimates published for various bullets.

I don’t have the equipment, desire or time to calculate my own BCs as some do. After all the errors will instantly show on paper. And errors won’t be any more catastrophic that a missed target. My friend who edited a couple of the COTW editions does do that type work. But he makes a living at it, while it’s only a hobby for me.