Nock Testing Report

[Larry Pletcher]

Steve and I spent the day timing the Nock Breech that Dan Phariss recently sent us.  Actually we first finished up a test that was held over from the series on cupped breeches.  We had timed the Chambers liner and cupped breech cleaning carefully between shots, but had not finished the dirty trial run.  At the top of the spreadsheet is that test.  We noted that the cupped breech was slower when compared to the flat breech in this trial.  We reported this last time too.  We have no explanation for this and report only that it was our finding.  We do not know why this is true.

We saw that the numbers we were getting were slower and wondered if there was something about our work that caused it.  So when the test was finished, we went back and tried the Chambers liner with the flat breech just to check ourselves.  These are shown just below the cupped breech results, and confirm that the difference is real.

------------------------------------

With the Nock Breech testing, we chose to start with the Chambers liner and the Phariss liner with the large diameter hole (.090) and exterior cone.  These distinctions are noted in the spread sheet, but from here on I’ll just call it the Phariss liner.

You will note that the barrel charge has been increased.  We discussed this change with Dan and decided to find the volume of the chamber and antechamber and use that amount for the Nock’s barrel charge.  We realize this changes a variable, but we wanted to test the Nock to its best advantage.  Also we did not want a void between the powder and the sabot – which seated on the chamber lip.

We added a step to the loading process with the Nock.  We wrapped the breech with a screw driver 4 times to settle powder into the antechamber.  We could see a difference in the powder level in the chamber before and after doing this.

Cleaning after was done the same way as before. Using compressed air was the only unconventional step.  Again we tested both cleaning carefully and doing no cleaning at all.  The results for these tests are in the lower part of the spreadsheet. (Showing the spreadsheet as a JPG may be a mistake.  Hope it's readable.  Not satisfied - redid it.)

                     
We were pleased with the way the Nock performed.  We were concerned that it would be a headache to manage.  However it handled both conditions quite well.  The difference between clean and dirty trials was small. And NONE of these trials were slow to human senses.  Even the slowest trials sounded the same.

Now a few quick comments:
There was much less smoke in the garage with the Nock even though we were using 50% more powder.

Ear plugs were necessary.

Please note trial 7 * on the Chambers clean trial.  When cleaning after Trial 7, a large chunk of fouling was blown out of the barrel.  So, after 2 slow trials and the chunk was gone the times returned to normal.

We got some interesting photos of the Nock in action.

This is a cone of fouling left when we carefully removed a WL liner.


Just fired - lights on.


Just fired - lights off


We have a couple more tests we want to run.  We want to do a small diameter liner sent by Dan and a TC liner donated by Roundball here on ALR.  The TC liner has a cavity in back and a exterior allen wrench-shaped cone.

We will wait to draw conclusions, but so far we like large diameter holes, large internal cavities (a la Chambers), and CLEAN vents.     We hope to finish the remaining liners with the Nock next week.

Regards,
Pletch

[Roger Fisher]

I for one thank you for your work on this.

[chapmans]

I was surprised and pleased by the way the Nock breech performed, and it was fast, clean or  dirty.
 I do wonder how it will perform in high humidity? Another thing we noticed was unburned powder scattered about, there were a few grains on a sheet of paper approx. 10 ft away that we put in a pile and it ignited ! Larry sweep the floor and we'll get a few more charges.  I have enjoyed these tests and look forward to the next project, after I get that bench gun chopped out.
   Steve C.

[Dphariss]

I have found the Nock in actual use to be VERY reliable.
It does not like low grade powder though.
I have not tried it with GOEX but I had some dirty Schuetzen (fouled more than the norm) and it would stop working in 3 shots due to fouling flakes plugging passages. Never does this with Swiss.
Humidity I cannot say. Never go out at 90-100% with a flint since here its raining. Have 60% right now cloudy and its supposed to snow, is snowing a few miles up the river. So the humidity I used to see in Iowa does not often occur here.
I would think it would be OK though being developed in England for fowling guns??

More great stuff.
Again a tip of the hat for our testers.
Dan

[Acer Saccharum]

Wow, cool info, guys.

Dan, I think you're right on the money with having the right powder.

I am impressed with the fact that the Nock is pretty darn consistent, dirty or clean.

Thanks so much for this hard work, all of you.

I have a Nock breech gun in my near future. My idea is to have a flint Schuetzen offhand bullet gun to shoot against the cartridge boys. I am a fair shot off hand, and I know this would bother them so bad, they might actually lose to me.

[Daryl]

Hmmm- might have to be a good shot offhand, Tom?  I'm a fair shot while Taylor is a good shot - so if you want to beat the bullet guys, maybe Taylor'll have to shoot your Scheutzen bullet rifle for you?

[northmn]

Look closely at the variability in times of the nock breech and you see that it is more consistant thatn the cupped breech.  May be even more so that the flat?  One of the results had a high of .078 whcih when thrown out () still showed a very consistant set of times in addition to which I can see not significant difference between the data for the Pharsis line either clean or dirty. Consistancy may be as much of a critical factor as timing?  The nocks were very consistant when you throw out one high.  As  a matter of fact the variability was less using the Chambers liner dirty than clean. The most important variable, to me, might be the total variance from the mean to the fastest as you cannot get a 000 time. When doing so, one sees a difference of about .012 across the boards. 

DP

[Daryl]

Good observation, DP.

[Larry Pletcher]

Look closely at the variability in times of the nock breech and you see that it is more consistant thatn the cupped breech.  May be even more so that the flat?  One of the results had a high of .078 whcih when thrown out () still showed a very consistant set of times in addition to which I can see not significant difference between the data for the Pharsis line either clean or dirty. Consistancy may be as much of a critical factor as timing?  The nocks were very consistant when you throw out one high.  As  a matter of fact the variability was less using the Chambers liner dirty than clean. The most important variable, to me, might be the total variance from the mean to the fastest as you cannot get a 000 time. When doing so, one sees a difference of about .012 across the boards. 

DP

DP,
I appreciate your thoughts.  We pretty much agree.  By the time we finish (probably Monday) I expect what we'll see is trends and not black and white results.   

We did like the consistency we found in the Nock when comparing clean vs dirty.  When we talked testing over with Dan, he mentioned that it was designed for fffg powder and that his experience was that Swiss would work better than other brands.  Knowing that we followed his advice and used Swiss fffg, wanting to get the best we could from the Nock.   I didn't ask Dan but I think if we would have wanted to use ffg, he would have suggested increasing the diameter of the hole leading back to the antechamber.  All this makes me speculate that when Nock, Manton, and others built a breech, they designed it specifically for the components (especially powder) that would be used in it.

The only flaw we saw was that at least once it appeared that a chunk of fouling increased the time.  In the trial noted, the compressed air blew it out the muzzle.  The next trial was back down to normal.

Monday we plan to do a couple more liners that we haven't checked yet.  I don't expect great differences, but who knows?  I will try to get all the averages on the same chart so it's easier to check through. 

Regards,
Pletch

[rich pierce]

Looking back at your flat breech data, it seems the Nock breech was not faster than a flat breech.  I'm not knocking it-  - am I correct?

[Larry Pletcher]

Looking back at your flat breech data, it seems the Nock breech was not faster than a flat breech.  I'm not knocking it-  - am I correct?

Rich,
Yes, you're right.  The flat breech was fast and consistent in the tests we ran.  The Nock was next, with the cupped breech  third.  I am working on getting all the averages on the same page so it is easier to digest.  Also we have two more liners to do on Monday.  I'll post a better chart this evening.  I want to look at clean vs dirty when I set up the chart. 
Regards,
Pletch

[Larry Pletcher]

Rich,
Here is a chart that contains everything to date.  The tests for MOnday are marked too.  I have been struggling to find a way to show data in columns and so far scanning a spreadsheet to a jpg is my best idea.  If someone has a better way, I'd appreciate your ideas.



One thing to note is that the outstanding time of the Pharris liner (.0309).  That liner used a huge diameter hole - larger than we would consider on a gun.  It passed a .09" drill bit.  If you excluded that test and looked at the remaining numbers in that column, you see a set of very consistent scores for a flat breech, clean or dirty.

And the Nock breech is not as fast over all, but is frighteningly consistent in its 4 scores.  We haven't done the small Pharris liner yet, but it still looks good.  BTW "frighteningly" probably isn't a good scientific term.

Regards,
Pletch

[chapmans]

I think it should be noted that, on the cupped breech, the touch hole is in front of the cup. I think the cup held around 5 grs. I don't know if this has an impact on the numbers or not. I'm still curious about why it is slower. By the way we would never know it was slower if it wasn't for these experiments,  I am certain that knowbody would be able to tell the difference between .035 and say .065 under field conditions.
  Steve C. 

[Dphariss]

I made the 3/32" liner (.093) to simulate the large diameter "plain" vent.
When I was a kid this was the typical unlined vent size.
When I made the breech for the 16 bore rifle I enlarged the passage to the antechamber until the powder, FFG, would flow into it ended at .177"  or #16. I think the hole in the test breech is about .150. I should have written this down. But I made what i thought would work with FFFG powder, I figured this was right since its basically a 45 caliber breech, then put everything in the mail.
My experience is that in use the 16 bore is very consistent. On rare occasion it will throw a slow shot and it REALLY messes me up since it IS so danged consistent. The other rifles do not seem to effect me like this.
Hopefully on April 4 I can get another flint shooter or two to shoot it. My son and I are the only ones to shoot it to date.

Dan

[northmn]

The Brown Bess replica I owned had about a 3/32 plain drilled unlined breech.  As stated it was very consistant.  It was an 11 bore so I did not mess up and fix it.  I still think there is some relation between bore size and touch hole diameter as far as utility.  I have a 25 Rayl coming and I really question if using a vent 1/3 the diameter of the bore would be wise.  As far as that goes a 1/16 is about 1/4 diameter. 

DP

[docwhite]

i HAVE BEEN READING THIS DETAILED STUFF WITH GREAT INTEREST. THERE'S LOTS OF HARD WORK HERE IN JUST A FEW NUMBERS. LET ME COMMENT THAT MANY LATE FLINT ERA ENGLISH DOUBLE FOWLERS HAD NOCK STYLE BREECHES AND WERE ALSO SELF PRIMING. THIS MEANS THAT THERE WAS A BIG HOLE THROUGH THE FRIZZEN COMMUNICATING WITH THE PAN. THROWING A CHARGE OF 3FG WOULD FILLTHE PAN. THE TOUCH-HOLES THAT I MEASURED ON THE SEVERAL ORIGINALS THAT I ONCE OWNED WERE 90-100 THOU IN DIAMETER ALL WITH PLATINUM LINED VENTS. ALL FIRED TERRIFICALLY FAST, RELOADED FAST AND WERE VERY EFFECTIVE GAME GUNS. I TOOK A LESSON FROM THIS EXPERIENCE AND HAVE FAVORED NOCK BREECHES WITH BIG LINERS AND BIG TOUCH-HOLES FOR MY ML BIG GAME RIFLES AS WELL. I HAVE NO EXPERIENCE WITH SMALL CALIBERS, LESS THAN 50, BUT STOPPING RIFLES FUNCTION TERRIFICALY WELL WITH 70-90 THOU TOUCH-HOLRS. OF COURSE, FINE ACCURARACY WAS NOT THE ISSUE, CLOSE RANGE POWER AND A FAST RELAOD WERE. THANKS FOR THE GREAT EFFORT. DOC

[Daryl]

DP- with a good lock, the 'issue' Chambers liner, about .051" or so, is just fine.  Pricking the vent before priming and firing will help ensure ignition.  The Bailes lock on my flint pistol, if carrying a good, sharp flint, gave almost instant ignition before drilling it out to .070", about the same speed, but was more reliable after drilling. I'd get the odd missfire (with small vent) due to not taking the time to prick the vent or making sure the flint's edge was in good shape.
  I don't think a vent smaller than Jim's vent will give very satisfying results.

Doc- good to see a response from you, but would you please not use 'caps'.  For some reason they are difficult to read.  This is a personal request only.

[Larry Pletcher]

Steve and I will start working with the Nock breech this morning and I have a couple of questions that have been batting around for the past few days.  My questions are based on this topic and the one on vent diameters and accuracy.

First I'm assuming that the late flint period "high Tech" English breeches were built for specific shooting needs.  I speculate that the majority of the Nocks went into large bores - foulers and perhaps big bore stalking rifles for dangerous game in Africa and India.  Further that there may have been little call for a small round ball target rifles or rifled small game guns.  (This is all based on my ignorance of the number of surviving English rifles from this period.  Please correct me if this isn't right.)

If this makes sense, then the Nock may be been designed with large touch holes.  Doc White's report of measuring originals points this way.  In these big bore foulers and stalking guns the high priority would have been reliability and speed and not tack-driving accuracy.

Jim Chambers' report about chunk guns shooters replacing liners  that exceeded 1/16"  would be an example of just the opposite.  Accuracy is EVERYTHING.   The shooter has plenty of time between shots to carefully maintain his piece - no regard here for charging tigers or doves flying out of range. 

Perhaps we are as unlikely to find a .32 cal. English ball rifle with a Nock breech as we are a .60 cal. chunk gun with a 3/32" vent.

This is all speculation and I need somebody to educate me here. 

Regards,
Pletch

[Daryl]

Makes sense to me, Larry.  Good extrapolation.

[Larry Pletcher]

Here is the spread sheet that includes todays testing and concludes the testing as well.



There are a number of ways to look at this data.  Undoubtedly there are more than I will think of.  Here are a few thoughts to get going:

First the flat breech was the fastest of the three.  Over all it was somewhat affected by lack of cleaning, but most of that was with the small vent.  All three of the tested vents were slower when not cleaned with the smallest affected the most. 

The Nock was second in speed, but was less affected by lack of cleaning, except with the small vent diameter.  The other vents were largely unaffected with the TC vent doing very well. 

The cupped breech was the slowest.  It was also the most affected by lack of cleaning.  This varied with the liner.  I have no theory about the reason.

Trying to compare vents is comparing apples to oranges.  All have a characteristic that makes it unique when looking at the group.   Certain groups of characteristics made  differences however.  Generally large vents combined with internal cavities lead to higher speeds.    The large diameter Pharris vent was very quick and consistent.  The Chambers had the disadvantage of a small diameter but did well.  The TC liner had a large vent and the internal cavity and was fast in the Nock breech.

If asked to list preferences, one needs to decide on priorities.  If speed is the only consideration, I would use the flat breech and a large diameter liner, an internal cavity or both.  With speed in mind I wished we would have timed the Chambers liner with a larger diameter hole.  The TC had a .073" hole, and did very well on the Nock breech.   I suspect the Chambers liner would have liked an equal sized hole.   

If the priority was accuracy, the large diameter holes may not have done well.  While we did not try to judge the accuracy potential, the work of others my show that diameters larger than 1/16" may be at an accuracy disadvantage.  I'll reserve judgement on this until I have a chance to do more work. 

I suspect than my ideal rifle would have a flat breech with a Chambers liner drilled to .067-.070 (at least until I'm convinced that a smaller diameter is more accurate.)  This range of vent size allows me the use of a pipe cleaner.  If the caliber was small I might be convinced to use a smaller vent.

I'm sure others will have differing opinions.  I hope something here will bring someone up for air ah, er, constructive comments.

Regards,
Pletch

[chapmans]

Larry,
  I really enjoyed participating in this experiment but I am also glad that it is finished, by looking at the spreadsheet it's hard to tell there were 200 shots fired in two different barrels, that's a lot of smoke and fire. I'm not sure what the outcome of this experiment is because there are no definite winners or losers. I was very suprised by the way the Nock breech performed, very consistant throughout, although I don't think I will ever have one because of the way the flat breech performed. I do know that I learned a lot about breeches and touch hole liners and I will  be a better flintlock shooter because of these experiments, along with the earlier ones. I really never gave much thought to the liners before I just put them in and shot the gun. I'm ready for the next experiment to begin!!
   Steve C.

[Dphariss]

Great data.
I am not really surprised at the outcome. Perhaps more so with the cupped breech than the Nock.
But this is testing and results are often not what is expected.
I wonder if the somewhat "front ignition" that takes place with the cupped breech is a factor.
The next thing of course would be to test a 10-20" piece of barrel with a service charge to see if this changes any thing. We could keep the testers in a lather if they covered every possible change.
In 20-20 hind sight I should have made a recessed breech with a flat bottom similar to the flat breech in the barrel stub.
This would have added a little to the knowledge since Manton developed the recessed breech specifically  to speed ignition.
The Nock was too for that matter.
But its been very infomative.
In real use I have found the 3/32" with no external cone to be less reliable.
I have found the small counterbored vent and the WL style to both be fast and reliable in use.
By far the best has been the recessed Nock type. Very reliable and consistent. However, I have not used the WL in  a "plain" breech either. For the "human timing machine" they are equal, the lock is being. Electronics show some difference.
It bed time.
But a big thank you to the testers is in order.

Dan

[roundball]

Here is the spread sheet that includes todays testing and concludes the testing as well.


The TC had a .073" hole, and did very well on the Nock breech.   I suspect the Chambers liner would have liked an equal sized hole.   

Pletch, I appreciate the fact that you included the redesigned T/C liner I sent you in your tests...I'm sure its not a liner anyone here would be interested in, but I knew from day one it was a vast improvement over, and very fast compared to, T/C's old style liner...nice to see the test results bore that out...thanks.
(PS: I thought the new liner hole size was supposed to be .070", but I'll defer to your measurement)

[Roger Fisher]

Well now just last night I installed one of Jim's WL liners in my 28 gauge smoothy in progress. After installation and interior trimming was complete, I pondered on should I or should I not open her up.   I worried on the subject for abt 30 seconds and opened her a tad more than `1/16th. She has a flat breech so I feel I did the 'right thingee (for a change)

[Larry Pletcher]

Well now just last night I installed one of Jim's WL liners in my 28 gauge smoothy in progress. After installation and interior trimming was complete, I pondered on should I or should I not open her up.   I worried on the subject for abt 30 seconds and opened her a tad more than `1/16th. She has a flat breech so I feel I did the 'right thingee (for a change)

Roger,
You likely noticed that our WL was drilled to .064"  We used a #52 bit.  Had we decided to go larger, a # 51 gives .067" and a #50 gives .070". I suspect that you will like the ignition your liner gives.  In a smooth bore I feel you have more options available than with a match rifle.  I like to use a pipe cleaner to clean the vent; I think you can with .064".  You can with a .067" hole.

Please report back your opinions as you fire the gun.   I'm always ready to learn.
Regards,
Pletch