February 2011 Experiments

[Larry Pletcher]

February 2011 Experiments

On Feb. 4, Steve and I timed a couple of locks and did a test to study the effect vent conditions have on ignition speeds. We wanted to compare ignition speeds of an empty, clean vent to a vent filled with priming powder. Tradition says that a filled vent is slower. We want to find out if the difference is measurable.

Lock Tests:

The first lock we timed was Ketland lock from Tip Curtis. Steve has a southern gun that this lock will go into. We waited to time it until it had the lock retaining hole drilled and tapped.
We installed a new flint and timed 20 trials using Swiss Null B for priming. The average for those trials was .037 seconds. This places it in the top 10 of reproduction locks I have timed if memory serves. In one trial we recorded an exceptionally fast time. It was either a computer glitch or the spark production was strong enough to trip the photo cell before the priming powder ignited. At this point we don’t know. One always worries that a previously unknown variable shows up, however these usually show as slow times rather than fast times. In either case the lock was very quick.

Next we went to the Sam Everly ball bearing lock. We are timing this lock with two different main spring weights. Today’s test uses the milder of two main springs. An earlier session recorded an average .042 seconds with a normal spring and Null B. Today we averaged .047 with the milder spring and Null B. The .042 (with Null B) places it among the faster locks. Coupled with great smoothness and easy on flints, it will go into a Lancaster I have in progress.

We also used the Sam Everly lock and the Tip Curtis lock to test a couple of other powders we had laying around. Steve had a can of Curtis and Harvey priming powder, and I had a can of Goex 1fg. We wanted to add these two powders to our time line of priming powder times.

The Curtis and Harvey can gave us an average of .057 (Everly) and .056 (Curtis Ketland). These times would rank Curtis and Harvey slower than Goex and Swiss. I can’t speculate as to the reason. It is an old can and the granules are larger than any of today’s priming powders.
We used the Everly lock to time the 1fg and got an average of .088. No surprises - here the slower times are not the fault of the lock.


Vent test

The purpose of this test was to see if there was a measurable delay in ignition when a straight cylinder vent was filled with priming powder. For the purpose of this experiment I will define this "fuse effect" as an ignition delay caused by the priming powder having to burn its way through the vent to ignite the main charge instead of "flashing" through the vent. I'm personally not fond of the term because it implies that we know what caused the delay. I like the term "hang fire" because it does not suggest a cause.

The test was set up using a fixture we used earlier to time lock ignition speeds. We used a “pistol” with a barrel stub, small Siler lock, and my computer with photo cells “looking” at the pan and barrel muzzle. The barrel is loaded with 30 gr 3fg and a sabot to hold powder in place. The pan is primed, and ignited with a red hot wire to eliminate lock variables. Between firings, the barrel is wiped with two patches and compressed air is blown through the vent to insure that the vent is clean. The pan is primed with Null B close to the barrel. The only difference between the two test phases was that the vent was completely empty in one, while in the other, we picked priming powder into the vent until no more would go in.

The barrel used was octagon 7/8” across the flats and was .45 caliber. It had a flat flint-type breech. The vent was a straight cylinder with a 1/16” diameter approximately .21 inches in length. Time starts when the pan photo cell is triggered and stops when the barrel photo cell is triggered. Thus barrel time is included in this test, however this obviously the same for both vent conditions.

We recorded 5 trials for each vent condition. The average time for the clean, empty vent was .028 seconds. The filled vent average was .031 seconds. As you would expect, the slowest time we recorded was in the filled vent phase (.0363). However the fastest time of the day was also in the filled vent phase (.0233). (We also did a single clean vent trial where we banked the prime away from the vent and recorded at time of .067 ”“ more than two times slower than the clean vent average.)

These averages are quite close together. We expected a larger difference because our ears tell us a hang fire has taken place. And, here is the most unusual finding. The fastest time (.0233) we recorded sounded as if it was a hang fire. The slowest time (.0363) recorded sounded like a sharp crack ”“ no hang fire - sounded like a .22 rim fire. This reinforces a belief I have long held that our eyes and ears are terrible tools for judging flint events.

This all makes me wonder what we are really hearing. Maybe our ears send us false information. Consider this: You are three shots into a target and have 3 tens. You shoot the 4th shot and it’s a nine. Sounded fast, but you think it was just you. You shoot the 5th shot, and it has an audible hang. You look through the scope, and no. 5 is back in the 10 ring. Maybe the fourth shot was slow, the fifth shot was fast, and your ears are at fault. With what we learned here, it could be possible. I truly don’t know the answer. Sometimes experiments leave you with more questions than answers. I do know that I trust my ears less than the numbers.

There are so many variables that can cause delays that in most cases it can be impossible to rule out all but one. That was the purpose in our experiment. We wanted to put a number on the amount of delay, if any, caused by packing a cylinder vent with priming powder.

The delays we found were measurable but not large enough to account for the delays we have measured in pan ignition - where the variables were flint edges, priming, particle size, and location of the prime in the pan. The other big factor is the delay caused by fouling in the vent. A vent full of priming is one thing, but a vent filled with fouling is quite another.

If I were to list three areas for delays based on my testing they would be:
1. Lack of good spark production from good flint edge
2. Improper priming location in the pan with good priming powder
3. Vent not absolutely clear of fouling

Regards,
Pletch

 

[Jim Evans]

Thanks for the info.

 

[Tom Compton]

As always, interesting and enlightening. Thank you.

 

[David W.]

Darn Pletch! I sure wish I could join you in some of your experiments. Being a mechanical engineer, I find your work very intriguing.

 

[CoyoteJoe]

I can't thank you enough Pletch for the excellent work you do to enlighten us all. I know you love doing it but thanks never the less.
As to eyes and ears being deceived, I think when I fire my own gun there is more to it than eyes and ears. In fact the eyes don't even enter into it since all I see is the sights and the target. Nor do ears have much to do with it, it is more the feel of the gun. I feel when the trigger breaks, I feel the flint strike and the frizzen flip and I feel the recoil. I'm not proposing more work for you but perhaps that is something that could be tested somehow.
The Army taught us budding wannabe spys that Morse code could not be sent by signal light faster than about five works per minute because the human eye could not discern shorter flashes. By ear however, even I passed 18 words per minute. With enough practice most people can do 40 wpm and some people can double that. The persons typing speed is the limitation, one can generally "hear" the code faster than their fingers can keep up. When you consider that a word is five letters and each letter may contain up to four dots or dashes plus a discernible space between each dot or dash and a longer interval between each letter a person copying code at 60 wpm is discerning very small intervals of time.

 

[Bearbait2]

Mr. Pletch,
Fascinating!
Thank you for sharing.
Best Wishes

 

[mazo kid]

Larry, thanks .....again!.....for all the work you do and share with us. Very fascinating stuff!

 

[BEP]

As always - interesting and well done. Thank you.

:hatsoff:

 

[Larry Pletcher]

Thank you all for your comments. It is fun to experiment with BP topics. When I first worked with this interface, it was for school applications, but when I found out I could time events to the nearest 1/10,000 of a second, it didn't take long to think of flintlocks.

Flintlock62 -- It is great fun to work with shooters on this. I lost a good friend to cancer a few years ago who first helped me. Ed was the guy who fired the shots when we got the photos of a patch separating from a round ball. In those days, we hashed out our plans at his barber shop. I haunted the place while we had a project going.

Steve Chapman is my partner in crime now days. Besides being a close friend, his great shooting skills have been a real plus. Whether it's offhand or bench he eliminates the human variables when we do range work. It's a plus to have such shooting experience to bounce ideas off of.

Your engineering skills would be welcome in our experiments. Developing the methods and controlling variables is so important that an engineers talent would be a key addition.

CoyoteJoe,
Your comments into the ear's response to Morse code gives me a different perspective on this problem. One thing that makes a difference is that holding the rifle and feeling the trigger and recoil gives one more intimate contact with the rifle and probably a better idea of ignition speed than pushing a space bar on a computer. I fire a plain, unset trigger while Steve fires a double set. Both of us feel that we're a better judge of ignition when our firing our guns. It would probably screw us up to fire each others.

Regards,
Pletch

 

[larry wv]

Thanks again Pletch. Good info as usual. :thumbsup: Larry

 

[hanshi]

Thanks for posting the test results, Pletch. I already had serious doubts concerning the "fuse effect". IMHO the distance through the vent to the main charge is simply too short for that sort of occurrence. And as I've mentioned before, I too, do not use that term and consider any hesitation a "hang fire". I know a hangfire when it happens with my gun; it's obvious to me. But my ears are not nearly sensitive enough to tell any difference in simple variable speeds of ignition.

 

[Zonie]

Many Thanks Pletch.

As I'm sure you know, your findings surprised me greatly.

After reading about your test results I guess I've been wrong in my assumptions.
Perhaps the hang fires I've seen and experienced over the years were caused by a delayed pan flash or one of the many different other things that can happen when a Flintlock fires? I'm sure we will never really know.

Again, my thanks. :thumbsup:

 

[ebiggs1]

This really interesting. I, too, wish I were there and could help with the tests. But I am glad you are willing to share your findings which I, for one, believe is right on, from my own shooting experience.
I don't have your electronic equipment to use but I do have a couple willing sons to use as test instruments. If you can't tell it on the firing line is it real?
Thanx again.

 

[paulvallandigham]

Great report, Larry. Thank you and your friend for all that work. Certainly the difference in the relative speeds of the various loads is so small as to be inaudible to the human ear. I also agree that our ears are very fallible.

I watched a TV show about amazing humans, and the first one showed Bob Munden, of Montana, shooting a SA revolver where all 6 shots are shot( fanning) and you see 6 puffs of smoke, but the sound of just one SHOT. His time for the 6 shots was less than a quarter of a second, but I didn't write it down. It was, however, "slow" enough that we should have been able to hear some different report. But, even on replay, all you hear" is the one shot.

So, don't trust your ears. And, if our eyes were so wonderful, no magician would ever be able to do tricks that fool us. :hatsoff: :hatsoff:

 

[joed1223]

Well done....thanks for sharing! :bow:

 

[hoochiepapa]

Thanks, Pletch! Takes a lot of the guesswork and believing "old wives tales" out of the mix. :hatsoff: