Breech timing starts tomorrow.

[Larry Pletcher]

Tomorrow morning Steve Chapman and I will begin the opening phases of the breech timing.  We will begin with the flat flint breech.  My thought is to use it as the control. 

Dan Pharris supplied us with a number of vent liners.  Jim Chambers is sending a couple of his liners, but they aren't here yet.  So tomorrow is probably more to develop a methodology for testing so we can minimize ourselves as a variable. 

I tried out the system tonight and found that we will need to work in dim lighting to keep the photo cells from triggering on room light.  I remember playing with ambient light before.  Tomorrow we will have the garage windows blocked, ceiling lights off, and a small desk lamp aimed to one side of the photo cells.

Tonight I used a plastic sabot on top of the powder to help hold the barrel charge in place - remember we're inside a garage.    It produced a nice pop on ignition.

Regards,
Pletch

[Greg Field]

Some of us stand in rapt attention . .. .

[Dphariss]

The sabot is a great idea.

Dan

[Larry Pletcher]

The first day of testing accomplished our main goals but also provided some unexpected results.  First we wanted some time to sort out the equipment.  There is usually some part that requires extra time.  This time it was a photo cell that had to be reset manually.   While it was a pain as we started, some adjustments made it easier as the day went on.  We did have ceiling lights off and windows blocked.  (This could not be done outside unless done at night.)

Conditions for the test seemed ideal.  Air temperature was 65 degrees and humidity was 52%.  The barrel charge was 20 gr Swiss fffg.  The priming was ¾ gr of Swiss NullB.  The barrel stub was rotated to vertical and powder and sabot were loaded.  After rotating it back down we primed the pan and pushed the primer as close to the vent as possible.  (Previous timing proved that the closer the prime was to the vent the faster it was.)  With computer reset, we heated a copper wire and ignited the pan.  After the shot we wiped the barrel with one wet patch 2 sides and a dry patch also 2 sides.  A whisk was used on the pan, followed by compressed air shot through the vent.  The barrel was reloaded for the next trial.

Steve Chapman worked with me today, and we shared the various jobs.  He worked on one side of the bench loading and cleaning the barrel, while I cleaned the vent, primed, fired, and handled the computer.  We got pretty efficient as the day went on.  We ended up firing somewhere between 50 and 60 shots.

The flat breech was used for all trials.  We did try three different vent liners, all made by Dan Pharris.  The first liner had an inside cavity.  Dan described it as “kinda like a White Lightning but with thicker walls.” The opening to the pan is 1/16”.  The second liner had a large vent hole (.09”) and an exterior cone.  The third was 1/16” at the surface and a larger counter bored inside. 

We timed two of the liners under different conditions.  The normal procedure was to do the cleaning as described above.  We also ran the same test over where we ignored any cleaning at all.  We wanted to see if one liner was superior to others when it was dirty or mismanaged.

Dan’s Chambers-like liner produced the following:
Clean: -------.0405 second average
Dirty:  -------.0433

The small counter-bored liner tested as follows:
Clean: ------.0398
Dirty:  ------.0474

The liner with the large hole and an exterior cone produced the following:
Clean: -------.0309

From earlier experience, ALL these times are quite good.  A shooter firing a rifle behaving this way would hear NO DIFFERENCE in these shots.  The human ear is simply not capable of hearing these differences.  All ignitions sounded like one sound.  The sound volume of the barrel did vary as fouling built during the “dirty” trials.  The volume increased as the fouling built up.

During the dirty trials we noted that the ignition generally slowed as fouling increased with the faster times more likely to be in the first help of the test and slower times in the later trials.  We likened this to a shooter on a woods walk and not wiping between shots.  While his ignition slowed during the walk, he would be unable to perceive the difference.  If his times were like ours he would think his rifle was performing normally.  (I am ignoring hang fires or pan flashes occurring because he mis-managed his lock.)

A couple of further observations might be that:
A liner with an inside cavity like the Chambers (or the Pharris one tested) is more forgiving in a rifle not wiped between shots.  The small hole in the counter-bored liner plugged completely on one occasion.

The large hole and exterior cone was an exceptions performer.  The “huge”.090 hole and the exterior cone was quite fast.

And last, we primed one shot with cannon powder – looked like chunks of coal in the pan. The time was .052  - not bad considering.

I hope Steve will add his impressions.  And Dan, please add any comments on the liners or any other impressions for that manner.

Regards,
Pletch

[chapmans]

    I think Larry coverd the days activities pretty well. So far everything tested "clean" was very close together timewise, but what we found out is maybe the coned liners were designed to help as the touchhole gets fouled, there was a good bit of difference between an almost straight thru hole and a coned one, as they got fouled. I am anxious to continue these experiments with the other breech types, I really don't see how the times could get much better, I would love to have my flint guns to go off with this speed and consistancy, but who knows maybe they do and I just can't percieve the difference. Also this experiment makes me want to redo the compression test we perfofmed because we have learned so much, about ignition, since it was done.
   Steve C.

[Dphariss]

I am not surprised the exterior coned vent was fast. My problem with them has always been that they get unreliable when they get fouled and will require the "cone" to be cleaned. Granted the exterior coned vents I have used had smaller diameter vents but were counter bored internally as well. I made this one just because I thought it was something that needed doing. I know that some use 3/32" plain drilled vents. I never really thought about its speed. But it does show that the 3/32 vent can be fast as well. I think there is a .078 "plain" vent as well.

A large vent will unload a considerable portion of the load (found in the gun cover) over just a few miles if the gun is in an "Easy Rider" rifle rack. This makes it impractical for me.

I consider this very important testing.
Everything we think about flintlock speed is based on "feel". By testing vents and locks and breech designs we can have something a little more factual.
The smaller counter bored liner is identical in its functional parts to the vents I make in 10x32 to reduce the hole diameter at the breech. They have always proven to be very reliable and fast as any for me, the testing seems to bear this out.
The WL design is identical to some drawings of English vent liners circa 1800 perhaps before. I have found it to be very reliable.

Dan

[Larry Pletcher]

I am not surprised the exterior coned vent was fast. My problem with them has always been that they get unreliable when they get fouled and will require the "cone" to be cleaned. Granted the exterior coned vents I have used had smaller diameter vents but were counter bored internally as well. I made this one just because I thought it was something that needed doing. I know that some use 3/32" plain drilled vents. I never really thought about its speed. But it does show that the 3/32 vent can be fast as well. I think there is a .078 "plain" vent as well.

A large vent will unload a considerable portion of the load (found in the gun cover) over just a few miles if the gun is in an "Easy Rider" rifle rack. This makes it impractical for me.

I consider this very important testing.
Everything we think about flintlock speed is based on "feel". By testing vents and locks and breech designs we can have something a little more factual.
The smaller counter bored liner is identical in its functional parts to the vents I make in 10x32 to reduce the hole diameter at the breech. They have always proven to be very reliable and fast as any for me, the testing seems to bear this out.
The WL design is identical to some drawings of English vent liners circa 1800 perhaps before. I have found it to be very reliable.
Dan

Good evening,
Sorry it took so long to reply.  I appreciate your comment about our perceptions based on "feel".   I hope these experiments will give us definitive answers where our human senses fall so far short.  In the testing on Tuesday I remember that Steve and I listened to a trial and commented that the trial sounded fast.  By the number, it was one of the slower trials.  Our ears are such poor measuring instruments.  Even the way your head is turned could effect your perception.

I thought some comments about trial stats would be in order.  The term statistical significance should be considered here.  Most of these averages are fairly close to each other.  There is a measurable difference between "clean" and  "dirty"  averages.  Statistically, the difference may be insignificant.  More important, might be "Real World Significance"  (my term).  Our senses simply can't tell the difference.

In 1990 I wrote the following in a MuzzleBlasts article timing L&R Durs Egg and Manton locks:

The point of all this is that if a shooter analyzes a shot and thinks to himself, "That sure was slow," it must have been VERY slow, probably three or four times as slow as usual.  Anything less than this, the shooter would not have noticed.  It is also possible that a slow shot was not caused by the lock at all.  Touch holes may cause more "slow" shots than poor lock ignition.

I still believe that.  Whether the cause of poor ignition was the flint, the lock, or the vent hole,  the shooter will only notice times substantially slower than normal.  In our test, ignition times of .022 sec. and .062 sec. sounded the same.

Regards,
Pletch

[Jim Chambers]

Larry,
My apologies for not sending the WL liners for the test.  I could swear that I gave those to you earlier.  Anyway,  we will send one of each size out tomorrow along with the drill and taps for installing them.  Many thanks for all the wonderful research you are doing.

[Larry Pletcher]

Larry,
My apologies for not sending the WL liners for the test.  I could swear that I gave those to you earlier.  Anyway,  we will send one of each size out tomorrow along with the drill and taps for installing them.  Many thanks for all the wonderful research you are doing.

Jim,
Thank you very much for your support with our experiments.  It's great to have vendor support, but it's even better when it comes from friends.  Thank you again.

In our current work we are only using the 5/16x32 size, so we will not need other sizes.  We  will likely modify the liner to use Dan Pharris' spanner wrench.  This will allow us to remove your liner from one breech set-up and move it to another.

Again, thank you for all you have done in support of experimentation.

Regards,
Pletch

[Dphariss]

In proving the Manton/Nock barrel I also proved a "plain breech" with a lined vent.
Now the plain breech 42" barrel produced pronounced touch hole "pop" when it fired.
This was with both the first shot with a nominal service load first shot and the proof load.
The Nock breech produced no "pop".
I assume this is a supersonic pop at the vent brought about by the gas jet.
I had thought that the "pop" of the Nock breech was obscured by the muzzle blast thinking the Nock produced more velocity but this is not possible.
But I now think, based on a post the Nock may have a reduced pressure at the vent.
More questions.

Dan

[Scott Bumpus]

Man o Man this is like watching a cliff hanger movie. i just can't wait to see what happens next!  As some have said already, THANKS  to yall for sharing this with us.  This information may well be the most advancement ever in flintlock performance.    Thanks again  Scott Bumpus

[Acer Saccharum]

Larry, and Dan, thanks for all the hard work.

There must be a pressure drop at the Nock vent, when compared to the flat breech.

I am sitting here, waiting to hear which one is the fastest breech. I have a bet with Dancey.

Acer

[Benedict]

Larry, and Dan, thanks for all the hard work.

There must be a pressure drop at the Nock vent, when compared to the flat breech.

I am sitting here, waiting to hear which one is the fastest breech. I have a bet with Dancey.

Acer

I just gotta ask, who bet on the flat breech?

Bruce

[Larry Pletcher]

Man o Man this is like watching a cliff hanger movie. i just can't wait to see what happens next!  As some have said already, THANKS  to yall for sharing this with us.  This information may well be the most advancement ever in flintlock performance.    Thanks again  Scott Bumpus

Our next step is to finish up the testing with the flat breech.  We have one more of Dan's liners to time, and we want to time a Chambers liner with this breech.  We will probably also time the liner sent to me by Bill (Roundball) This is a 1/4x28 liner so it will be necessary to drill and tap on the opposite flat from where we're working now.  Dan has already done that to the Nock Breech. 

With all liners timed we will likely go to the dished (cupped) flint breech and repeat the timing with the various liners.  At this point we may choose the most promising liners to continue.   Following that we'll move to the Nock Breech.

I thought you might be interested in the "lab??" we're using for this experiment.  It is one side of a garage normally housing antique cars.  Our space is 2 bays end to end. 


I weighed all priming in my basement and placed them in empty cartridge cases.


Here is what 3/4 grain of Swiss Null B looks like.

The next three pics show the overall setup from a couple of angles.







A close up of the barrel, photo cells and shield.


The computer and fixture from my side.


I worked on the far side with priming and firing.  Steve worked this near side - loading and cleaning.


This is how we caught the sabots after firing.  We used them over and over.


That gives you the rough idea.  Because the garage can be heated, we have a pretty good working environment and reasonable control over temp and humidity.

Regards,
Pletch

[Larry Pletcher]

Larry, and Dan, thanks for all the hard work.
There must be a pressure drop at the Nock vent, when compared to the flat breech.

I am sitting here, waiting to hear which one is the fastest breech. I have a bet with Dancey.
Acer

Let me give credit also to Steve Chapman who did machining to fit the lock plate to the barrels and Nock breech.  He also helped with the cleaning and loading during the first timing session.





Steve has been a partner in crime and shares my interest in what makes a flintlock tick.
Regards,
Pletch 

[Dphariss]

Larry, and Dan, thanks for all the hard work.

There must be a pressure drop at the Nock vent, when compared to the flat breech.

I am sitting here, waiting to hear which one is the fastest breech. I have a bet with Dancey.

Acer

Thats the only thing I can think of that would cause what I heard, or didn't, in proving the barrels.
One of the objectives of Nock, or so it was written by Greener I think, was to reduce the amount of powder blown out the vent???
 The next logical step would be to test velocities is a 12-18" barrel and see if the Nock does better than a plain breech in the same barrel. Greener in the 1830s stated it did but was not as good (based on distance a ball would travel with a given load) as his design...
To my way of thinking it should be the fastest but we will see...
Dan

[Robert Wolfe]

Love that computer! I am sure it does just fine but it looks like it has some years behind it. The Smithsonian may be calling soon..............

Great stuff.

[Larry Pletcher]

Love that computer! I am sure it does just fine but it looks like it has some years behind it. The Smithsonian may be calling soon..............
Great stuff.

This is the computer I hauled to the Seminar at W. Kentucky in '88 to time locks with Gary Brumfield.    The physics interface will work with an Apple IIe only, so when it dies, I'm done. You can see the interface in the 3rd and 7th photos between the computer and the fixture.

[David Price]

Larry,
Those pictures cannot be the lab where you are doing the testing.  WHERE IS THE SMOKE.

Seriously,  how do you get rid of all the smoke.  I expected you guys to look like a couple of coal miners.

[Eric Kettenburg]

Whewee!  It must be getting pretty stinky in there!

[Larry Pletcher]

Larry,
Those pictures cannot be the lab where you are doing the testing.  WHERE IS THE SMOKE.
Seriously,  how do you get rid of all the smoke.  I expected you guys to look like a couple of coal miners.

Hi David,
It is the same place, but I cheated and took the photos two days later.  During a run of trials it does get pretty cloudy in there.   To solve that we run a series of trials and while we're averaging and preparing for the next set, we open the garage doors for a few minutes.   Even 5 minutes makes a big difference.   The outside temp was nearly 50 so we heated more to keep humidity the same than controling temp.
The temp might drop briefly but nothing major.  The humidity stayed within 5% if I remember correctly.

Eric,
It smelled a bit, but what with all the stuff that oooozes from three old cars, the BP smoke was rather pleasant.

Regards,
Pletch

[chapmans]

David,
  When the smoke got too thick we just opened up the overhead door and it cleared out pretty fast, luckily the temp outside was around 50 so it didn't take long to warm the shop back up. I don't know when we will have another warm spell so we can continue the fun.
   Steve C.

Larry,
 You type faster than me.    Smell what smell?
 

[Dphariss]

Love that computer! I am sure it does just fine but it looks like it has some years behind it. The Smithsonian may be calling soon..............
Great stuff.

This is the computer I hauled to the Seminar at W. Kentucky in '88 to time locks with Gary Brumfield.    The physics interface will work with an Apple IIe only, so when it dies, I'm done. You can see the interface in the 3rd and 7th photos between the computer and the fixture.

I have a II GS out in the shop. IIe are not that hard to find. Try ebay for a spare. I had one for awhile, think I finally scrapped it. Working they go for 10-20 bucks IIRC.
But they are pretty simple and durable.


Dan

[Larry Pletcher]

I have a II GS out in the shop. IIe are not that hard to find. Try ebay for a spare. I had one for awhile, think I finally scrapped it. Working they go for 10-20 bucks IIRC.
But they are pretty simple and durable.
Dan

Dan,
When my school system changed over I scrounged some components.  I have a couple of extra drives, etc.  Have to check to see what I really do have.  As you say simple, durable, and fine for doing this kind of crunch work. 

My concern is the interface.  It was custom made in a local college summer class for physics teachers.  That will be hard to replace. 

Regards,
Pletch