Magnum C&B loads, Air Gap?

[Classanr]

=== question ===
Is NAA encouraging the employment of an air gap in the BP Magnums?

=== reference ===
The following paragraph of loading instruction is found in the current NAA Cap&Ball manual:
"Using the furnished powder measure (which holds 2.5 grains black powder FFFFH or Pyrodex, for the NAA Companion LR, and 4 grains for the NAA Companion Magnum), pour into each chamber 1 (one) level measure full. CAUTION - do not overload or use other than the recommended powder."

=== observations ===
1. We note that 4.0 grains 4fg Black, when placed into a BP Magnum cylinder, leaves an air gap between powder and projectile.  Error in measurement equipment.  See postings below.

2. We note that the "powder chamber" (from internal "step" to nipple) can hold up to 6 grains 4fg Black.
Thus the recommended max load is only 2/3rds of the charge space, and the air gap is 50% of the powder space.    Error in measurement equipment.  See postings below.

3. In a posting about #4 buck, TwoGunJayne reiterates the "leave no air gap" general rule
http://naaminis.com/smf/index.php?PHPSESSID=bb9bd18dbb0e232b4c0df3af3688c74b&topic=3261.msg63916#msg63916

Thank you TwoGunJayne for prodding us to review our work.
Now the question revolves around a difference between .3ml scoop (which is 4.5gr vol) and the 4.0gr vol owner manual "max".  See postings below.

[TwoGunJayne]

Strange, when using the .3cc dipper, I note no real air gap in my 4" BP Earl?

[Classanr]

Strange, when using the .3cc dipper, I note no real air gap in my 4" BP Earl?

Yes, that's what I've seen you report in the past, which is why I brought the subject up here.  The "We" in this case are in separate states, so it is hard to look over each other's shoulder when trials are being made.  I will persue this matter on "our" end for further details.
This "surprise" arose in our efforts to convert a flash-pan flask to "quick-load" NAA cylinders.  Maybe the narrow drop is "fluffing up" the powder?  Maybe different brands of BP are making a difference?  Maybe somebody on "Our" team is making an error in measurements?  Maybe the moons are not aligned?  The C&B cylinder is for a Magnum Companion, if that might make a difference?

Will be back with further observations after we go into a huddle.

[TwoGunJayne]

Try throwing a charge from your flask into the stock yellow dipper?

I think you're right in that it may be fluffing up the powder. I really like the idea of what you're talking about. I want one too, if you get it ironed out.

[Classanr]

More information to cogitate:

By definition, a 0.3 ml dipper yields 4.5gr vol
The Lee Dipper table states that by weight, a 0.3 ml dipper yields:

BLACK FFFFG 4.50
BLACK FFFG 4.80
BLACK FFG 4.40
BLACK FG 4.20

Could there be a typo in that table, when corrected would state the weight of 4Fg at 5.40?
Disregarding weight, a 0.3 dipper would be throwing 4.5gr vol, not the "max" called for by the NAA user manual of 4.0gr vol.
Thus one-dipper-full would (by NAA's manual) be an over-charge?

I received this note from the other team member:
"...scale was acting up the other night. Today I went down to see about consistently throwing charges and the weights were 4.4->5 grains and powder was at or slightly above the powder chamber."

OK, so he was not throwing by vol but by weight.  Which means the experimental version of the automatic dispenser seems to be doing a reasonable job.

More on this subject to come, but there still seems to be a question of "is it 4gr max, or 4.5gr max?"

[Classanr]

We are still working on this.
Naturally, it is not the only project.
But our personal interest is high, so it won't fall between the cracks.

[TwoGunJayne]

Keep us posted, I want one.

[scbuxton]

Hello classanr i didn't realize that you had been bitten by the mini bug. Welcome to the forum I'm sure that we'll all benefit from your postings.
I have three NAA c&b's -companion,  super companion and four inch earl . I have shot each quite a bit and have loaded each to the point of compressing powder to get the lead  flush with the cylinder face.  Never a problem with overloads. Just not enough powder to break anything.   Same with light loads, air gap. Not recomended but not disastrous either.  Tiny little chamber will only generate so much pressure with black powder.
If you load per NAA instructions and even come close to getting it right , you will be ok.
You are experienced with black powder shooting and you realize that measurements are not as critical as with smokeless.

[Classanr]

We are still working on how to throw a .3cc charge from a single hand-held device directly into the chamber.  In the mean time, my 4" Earl came in.  After a cleaning, I loaded it up with digital calipers.

First, a large thank you to TwoGunJayne for the reference months back to tannenberg gonne.  Truly, these NAA C&B's do not burn inside like straight-walled BP chambers burn.  A repro .44 C&B is like a gasoline engine.  A NAA .22mag C&B is like a diesel engine.  They both produce power, but they do it differently.  Thus, the rules are somewhat different in how best to fuel them.

The result of my measurements is the following chamber cutaway and initial discussion on how this gun is designed to work.  We hope it will be a useful reference for C&B mag users.

trac-r.com/c&b/pdf/CutawayChamberView.pdf

Testing of powders will be done some time in May.  Those already shooting these mag C&Bs pretty much know what works and what does not base on emperical trial and error.  They suffer the slings and arrows of gasoline-engine safety-meisters.

Possibly our efforts will catalog where all the foul lines are in the NAA BP ballpark, and the game can go on without rancor.

I welcome all naysayers to speak up if they wish, especially if you have already blowed up yer gun trying X-Y-or-Z.

Classanr

[TwoGunJayne]

Five star post sir, http://trac-r.com/c&b/pdf/CutawayChamberView.pdf

Pressing #4 buck roundball into the chamber DOES give a touch of powder compression, since it's basically the opposite of a hollow base. I've had pretty good roundball (small game) results with Triple 7 3f, though 4f straight black is suggested by the maker. I wonder if the compression balances out a coarser powder? Haven't gotten my hands on a can of true black since Obama... the local shops within a reasonable drive only carry BP subs and BP shipping is outrageous or there are hefty minimum orders. I'm just saying that there's hope with 777 and Pyrodex, not the end of the world even shooting 3f instead of 4f.

At least we have some food for thought.

I absolutely love, love, love my 4" BP Earl. If NAA ever makes a 6", I'm getting one.

Getting top performance is one thing, but noticing that "moderate performance" still works is good too. The NAA bullet at even 800 fps can still kill things. I've used those ballistics for trapping and small game.

I'd love to know how to get 1500 fps without fragging the caps and tying up the cylinder. Please keep up the good work, Classanr.

[Classanr]

Thank you for the stars.

I note that the NAA nipples have a wider flame hole than do my Piettas.
It might be necessary to "abbreviate" the holes in the NAA.

Working only on theory and drawing from decades of mistakes, I will bring myself up to speed by learning the behavior of the NAA cylinder.

I will start low power, of course.
I will start with Win #11 mag caps.
The objective is to get the entire powder load to ignite before the bullet unseats itself.

I have considerable experience with #4 in .223 - I would be remiss to not try those as well.  I have BlackMZ which *loves* compression and is very easy to ignite.  But I don't expect it to behave well in the NAA except as a "900fps" load, and that only with the #4.  Not that that is bad, but today I ordered 2500 NAA 30gr because they clearly are designed for this chamber, and breaking the 1.2k barrier will require using the best-suited smokeless and the best-suited bullet.

Towards that end, I am taking the direction of using the fastest shotgun powder that will reliably ignite at low pressures, with the expectation of developing over 12,000psi in a very steep time curve - a spike if I can do it.  I don't want 24,000psi over a long time.  The barrel is too short for that, and as you point out, the caps will push out.

I believe these cylinders are capable of 24,000 psi.  Certainly the same cylinder bored with larger chambers for the .22WMR can stand the 24kpsi.  These C&B have more metal aorund the powder chamber.  I think the limit will be the containment at the caps.  I might just glue the suckers on.

Please, tell me your experiences with fragged caps.  Maybe I can learn the easy way?

What, pray tell, have you determined to be the cause that "ties up the cylinder"?  Does the pin flex?  Does the cylinder rotate counter to the hand?  Is the off-center bolt an issue?

[TwoGunJayne]

I'll share what I've learned. Hope I'm right!

Sometimes when shooting the C&B, the caps "blow up" and shred. Bits of metal stick out from where they're supposed to be and the more caps that do it, the less likely to be able to get all 5 shots without wiggling and finessing the cylinder.

I suspect that during the loading process, I'm shaking powder through the flash hole into the cap area. I also always carry the thing in the NAA leather flap holster, muzzle down. I noticed that seems to reduce my problems. Perhaps it's my imagination, but holding the piece muzzle-down and shaking it a bit after loading may help... or maybe it's all in my head. If I actually DID use 4F, I wonder if a "duplex" load would be more reliable... that is... 3f near the flash hole and top with 4f to prevent powder migration.

CCI caps have always been really stubborn to light and usually frag. I think they're too hard and hot for this pistol. Haven't tried the Winchesters, but always used the recommended Remington pistol caps. They have always worked for me and I'm a bit loathe to mess with success.

The C&B is a strange balancing act, with loss of velocity when the cap fragments. This shows up on chronograph tests.

Caps backing out or blowing up seems to be the only tie-up situation with me and my equipment.

If you don't mind me asking sir, do you have any measurement equipment to try to determine actual chamber pressure or are you using "best guess" references such as "Quick Load?"

http://www.neconos.com/details3.htm

Unfortunately, the advanced chamber design of the NAA C&B guns would throw references like QuickLoad out of the window, I think. From everything I've read, it makes the powder act totally differently than a straight wall chamber.

[I]

I had an idea. A super-thin disk of flash paper in the chamber might stop powder migration with no downsides. Nitrocellulose paper, perhaps. A bag of 1000 would be tiny.

[Classanr]

I had an idea. A super-thin disk of flash paper in the chamber might stop powder migration with no downsides. Nitrocellulose paper, perhaps. A bag of 1000 would be tiny.

I was going to carefully place one grain of BlackMZ over the hole.  Lights really easy.  The paper idea is vastly superior to mine.  Another option is to put in a light layer of TrailBoss.  Those are donut-like flat discs "flakes" and would not mess up a BP 4F ignition.

Because I am working towards 22MAG velocities, I will be using smokeless in these tests.  Each smokeless will be evaluated for "fitness" in the flash hole.  Come to think of it, a light layer of BlackMZ or TrailBoss as the underside of a duplex load might be just the ticket for quickly bringing the charge to adiabatic pressures (which is what is *supposed* to light off the rest of the charge in one detonation).

[Classanr]

... The C&B is a strange balancing act... If you don't mind me asking sir, do you have any measurement equipment to try to determine actual chamber pressure or are you using "best guess" references such as "Quick Load?"

http://www.neconos.com/details3.htm

Unfortunately, the advanced chamber design of the NAA C&B guns would throw references like QuickLoad out of the window, I think. From everything I've read, it makes the powder act totally differently than a straight wall chamber.

I have an excellent chronograph.  I was going to use RSI's pressure equipment with Pressure Trace software, but when I asked the owner where I should put the strain gauge, he flatly stated that the strain gauge would not work on a revolver.  Bummer.  He explained that first, it has to fit on the chamber perpendicular to the axis of the chamber, between the cylinder and the strap.  Can't do that.  Second, the strap stretches longitudinally, so measurements there would be meaningless.  Third, affixing the gauge on the barrel is too far away from the point of ignition.

I have always been suspect of QuickExplode.  It is great within known limits.  Up to now, I have focused on cat sneeze loads, wherein the issue is using too little of the wrong powder and making shrapnel.

What I will be doing is to carefully evaluate the history of each powder and calculate for myself what the probable max loads will be.  I would love to peek at Dick Casull's lab notes.  He has blowed up a few of these to find the limits, but I suspect he cannot publish that data without causing BATFE alarm as to the commercial use of a BP pistol.

You nailed it when you say the powder acts totally differently when the NAA 22MAG C&B is loaded as designed.  Basically, the tannenberg gonne depends on a controlled secondary explosion effect.  With underloads I studiously avoided same.  Now I will strive to make 'em happen.

As an aside, were you aware that Diesel's first engine ran on coal dust?  It was too abrasive, so he started experimenting in the liquid fuels area.  We are just going back to the dust power source here.

[I]

These posts make me glad that I am here. This thread is the 1% of gun forums.

[Classanr]

...Pressing #4 buck roundball into the chamber DOES give a touch of powder compression, since it's basically the opposite of a hollow base. I've had pretty good roundball (small game) results with Triple 7 3f, though 4f straight black is suggested by the maker. I wonder if the compression balances out a coarser powder?...

777, BlackMZ, Pyrodex are powders designed to be ignited by plasma flame travel.  In other words, they are designed to be compressed to keep the particles as close as possible together for faster rate of ignition.

Let me step tangentally here to explain the problem of unusually slow ignition of an intentionally slow powder that is loosely distributed and thus not able to ignite fast enough as designed.  What happens in a bottle-necked case, and sometimes in straight-walled cases, is that the powder gasses off without ignition and the chamber pressure (and thus temperature) reaches a critical point, then the entire lot goes off in a detonation.  Simply put, there was not enough fuel to cool a too-rapid temperature rise.  KaBOOM!.  The proper solution is to *add more powder* to slow down the gassification and encourage the plasma flame travel.  I bet you never thought of powder that way, eh?  Have you ever put too much gasoline in your car's engine?  That is known as "flooding the engine" and it prevents it from starting.  "Over-choking" (too much fuel for the air) will also kill an engine.  In NAA C&B guns, too much BP will choke the fire.

It seems counter-intuitive, but what we don't want happening in most guns (just a tad too little fuel) is exactly what the tannenberg principle counts on.  We want a little bit of the powder to ignite, but the rest of the powder to "wait just a bit".  We don't want plasma flame travel throughout the powder.  We want the rest of the powder to gassify, *then to detonate* when lit by the suddenly-high pressure.  This is, by the way, the principle of the fuel-air bomb.  Much more energy can be released in a shorter time from less fuel if converted to a gas before ignition.

Back to TGJ's question about compression.  Some powders are engineered to ignite better when compressed.  The compression presses the granules closer together to promote granule-to-granule flame travel.  Pyrodex pills are the best example of how some powders burn faster when pressed together.  Although harder to start, a 30gr Pyrodex pill will release much more energy than will 30gr Pyrodex loose.  Not that there are 22cal Pyrodex pills, but the 44 and 50 pills serve as examples for how some powders are engineered to work better when compressed.

In all commercial powders, the rate of gassification (and thus the rate of gas expansion) is intentionally retarded by coatings and granule shape/size.  The "black" in black powder granules is graphite, a flame retardant.  The larger the granules, the harder to ignite, and the more space there is between granules to dissuade flame travel.

Consequently, compressing some powders will indeed cause them to exude more energy than if filled loosely into the NAA powder chamber.  This is because the powder is engineered to burn slower when less packed, faster when packed.

4F black works well in the NAA guns, but BP does not carry as much energy per grain weight than does smokeless.  They are of totally different chemistry.  Therefore, once the optimal granule size and dispersion is reached for BP in the NAA powder chamber, there will be no improvement by either "filling up" or by "packing in" more powder.  Paradoxically, the excess powder will cool down the ignition and retard the time of release of the energy.  In other words, velocity will be lost when "more than the right amount" of 4F BP is packed in.

BP substitutes, on the other hand, usually require compression to burn fast.  They will be poor energy producers in the NAAs unless they *are* compressed.  This is why some success is achieved by cramming in as much powder as possible - these powders improve their burn via compression.

However, compression forces the smaller NAA powder chamber to under-perform compared to what it *can* do.  Unfortunately, it is not possible in these NAA guns to bring *compressed* powder to a state of gassification before ignition.  As an empirical result, larger amounts of these powders (that require compression to burn well) will perform not much better (if at any better at all) than the appropriate smaller amount of loose 4F BP.  You will note that NAA does not recommend any other powder or BP substitute (none, zilch, zero).

TGJ and others will grind a BP substitute to dust.  If not compressed when loaded, I would expect these home-brewed fluffies to perform on par with 4F BP, and maybe a bit better, but not by much.

Until a high-energy powder is loaded loosely into the NAA 22MAG powder chamber, one can only expect 22LR performance (with a 30gr bullet or 21gr ball).

Here is my take on pressure in these guns:
If 12,000 psi is the max achievable with BP, and the cylinder/barrel/frame is capable of 24,000 psi, then smokeless powder becomes a necessity to raise the velocity in a meaningful manner.  If 12,000 psi with BP will push a 30gr slug 900fps+, then 24,000 psi with smokeless gives rise to the possibility of 1,500fps.

[I]

I have another suggestion. When you work out your paper falsh cartridge, send me a few cases. Antique design, eh friend?

[Classanr]

I am of the opinion that a full paper cart will get in the way of how the powder needs to work.  A single layer of flash paper across the flash hole, however, was a good idea.  Instead, we are working on a filling device to accurately dispense the correct amount.  The gentleman making them uses hollow silver antique knife handles.  They are rather cool in looks.

[I]

Sounds most epic, friend.

[scbuxton]

Classanr when you get much past the 900fps mark, leading will start to become an issue. Alox helps reduce the leading .

[Classanr]

Classanr when you get much past the 900fps mark, leading will start to become an issue. Alox helps reduce the leading .

Excellent point, one that I factored in but I did not insert into the already epic text.  Shooting smokeless also allows me to moly-coat the barrel, which I find is useful to reduce the effects of leading and (somewhat) increase the velocity.

In addition, after pre-treating the bullets with Alox, then waiting 24 hours for the Alox to glaze, I will dip each bullet into a shallow pan of Gunslinger's 50/50 beeswax/olive oil, wetting the bullet from concave base to the bottom of the .224 driving band.  When seated into the powder chamber, a small wax sealing ring will be created by the seating process, eliminating the need for over-bullet "lube".

[Classanr]

The only #11 caps I could find were Winchester #11 magnums.  I wanted to see how they would push an airgun pellet.

The good news is that these spit copious sparks three feet out the 4" Earl when shot without powder, but behind a .22 lead airgun pellet.

The bad news is that most of the Winchester #11 mag caps had so much primer that they stood proud over the nipple.  I had to put about 20lbs of pressure (slooooowly) on each the cap, one at a time, to get them to sit flush with the cylinder surface.

The good news was that pressing hard on the caps to seat them stopped the caps from falling off.  Otherwise, #11 Winchesters tend to slide on/off with a simple tilt of the cylinder.

These Winchester #11 caps, on firing, split but did not fragment.  Further testing with powder and ball/bullet will uncover how these caps perform under pressure.

I would discourage purchasing Winchester #11 caps for the NAA C&B.  Unfortunately, I have 695 more to go, and they do go bang reliably.

[jaxenro]

How did the testing go? Would like to see the loaders made from silver handles