Newbie with Mortimer

[EdsPlace]

Hi all.  I just purchased my first flinter, a Pedersoli Mortimer new from Dixie Gunworks.  I haven't shot it yet.  Upon inspection, it has some surprises.  It has what is called a "patent breech"; measurement shows 1.25" from face of breech plug to vent hole.  Some further research says this may, or may not, be a reliability problem.  I have not dissassembled yet, but have been told the hole in the breech face is approx. 0.020 inches.  How long is this pipe?  I don't know.  In any case, I have read a recommendation that the "pipe" be opened to 5/16", and the liner be coned.  I have the equipment and expertise to do this, but have some reservations.  What if I do one operation and not the other?  Does this even make sense?  I would like to hear from the voice of experience.  Any takers?

[D. Taylor Sapergia]

Edsplace:  First, welcome to this site!  You'll like it here.

I have only seen one Mortimer, and it was a shotgun barreled version.  Ignition is very reliable as far as the breech and vent are concerned, although I was commissioned to do some tuning of the lock.
I do not understand your description.  Would you post a picture of the breech, and it's relationship to the pan of the lock?
Are you describing the internal machining of the breech plug?  what 'pipe' do you refer to?

[SCLoyalist]

No experience, and I didn't even stay at a Holiday Inn Express last night, but I'd wait until I knew something was broke before I went trying to fix it.   A trip to the range to assess the reliability of ignition might be worthwhile.

That said, here's a discussion that might answer some of your questions:
http://muzzleloadermag.infopop.cc/eve/forums/a/tpc/f/20610091/m/5054000928          If I'm reading it and your questions right, you'd be opening up the "pipe" for a length of approximately 1/2".

Good luck with it.  SCL

[Hungry Horse]

It sounds like you are describing a problem similar to the problem with the lower barrel on the O/U Berreta shotguns. The flash channel was so long, and small diameter, and far away from the ignition source, that they rarely fired, or fired slow. Opening up the channel was the answer in that case. Just remember this is a part of the gun, that if done wrong, can easily turn it into a wall hanger.

                     Hungry Horse

[galamb]

I believe I "get" what you are talking about since I only build with Patent breeches.

There can be an issue with powder/fouling bridging over the channel that leads from the face of the plug back to your flash channel if it is too small resulting in "fail to fire" situations or minimally, a long hang fire.

The debate becomes "what is too small" and "in comparison to what".

I always open the channel to the next major "sub-caliber" below the barrel caliber. What I mean is, if the barrel is a 50 cal, I bore out the channel to .45" (.40 for a 45 cal etc).

.20", or twenty cal is pretty tiny for a channel - most builders plugs come with (minimally) a .26" channel which I (personally) find super tiny, but sufficient for a 32 cal which is probably why they are cut as such.

Anyhow, here's a diagram that illustrates what I'm referring to (if I understood you correctly).

[Bob Roller]

On another forum,several years ago I read about one of these "Mortimers"and the breech plug had what that writer described as a flue of about .100. This is/was an attempt to recreate the Nock Patent breech.My fix was to bore this breech out with a .358 drill like I used on the scratch built 58 caliber rifle I built.I also recommend
changing the vent to a Chambers or a similar one.My 58 went off like a center fire and if the lock on yours is working right,it should as well but ONLY after modifying it.

Bob Roller

[EdsPlace]

OK, what is good about the patent breech, and what is bad?  I can't for the life of me understand why two ignition chambers are better than one?  When the cock falls, we should go bang, n'est pas?  Doesn't all this extra just add  ignition time?

[galamb]

I consider the patent breech "safer".

It may have been initially designed to speed ignition (by some accounts) but I personally don't care if rifle A has an ignition time 3 milliseconds faster than rifle B.

I consider it a "must" (patent breech) particularly in thinner walled barrels. The liner or drum is installed into the plug, not through the barrel wall which may be quite thin.

Even on a heavier walled barrel, because the plug channel/chamber is "less than bore size" there is still "more meat" for the liner or the drum to fasten in to. And when it comes to safety, MORE is ALWAYS better, particularly with a caplock where you are essentially setting off a pipe bomb about 4" in front of your right eye.

For that reason alone I will live with the "greater chance of fouling" and all that goes along with that.

There is a number of styles of patent breeches out there, some may be better than others.

Here's some that you may come across:

PERCUSSION TYPES (compared to the "typical" drum style)



FLINT TYPES (compared to the liner through the barrel wall)




Of course, if we all agreed about everything there would be but a single rifle available  

All my rifles, flint or cap, have a "chambered" patent breech and I personally do not see any disadvantage, difficulty in cleaning, fail to fire, channel/chamber bridging or any of the other (noted) issues with a patent breech. And not to be confused with "hooked" breeches which allow easy removal for barrel cleaning. With one exception (a Hawken Plains/Mountain rifle), I use "fixed" breeches.

[smylee grouch]

Do as the others have said, shoot it first, you might find it works just fine the way it is. My sons 58 flinter with the same style breech has an antichamber of around .2 in dia. and it works great.

[Standing Bear]

Yep, shoot it first. Even then if there is a problem with ignition after the priming flashes first step would be to open the touch hole to 5/64 or so. I say after pan flash as a friend has a Mortimer that wasn't sparking reliably. He was convinced the frizzen was mid shaped. Installed a longer flint. Problem solved.

I have a similar breech plug in my .54 flint and not having any problems. Also don't have a problem with my Beretta O/U shot gun -either barrel.
TC

[Vomitus]

On another forum,several years ago I read about one of these "Mortimers"and the breech plug had what that writer described as a flue of about .100. This is/was an attempt to recreate the Nock Patent breech.My fix was to bore this breech out with a .358 drill like I used on the scratch built 58 caliber rifle I built.I also recommend
changing the vent to a Chambers or a similar one.My 58 went off like a center fire and if the lock on yours is working right,it should as well but ONLY after modifying it.

Bob Roller

Bob, excuse my ignorance, but wouldn't it be even better to drill that antichamber out to .58 so it would be easier to clean? One jag, one diameter, with no place for fouling build up?
Maybe I'm missing something?

[Bob Roller]

Be CAREFUL with drilling out a chambered breech plug.IF you drill a 3/4x16 thread to 58 caliber you just might weaken the threads. Let's assume the plug OD is .750 and you bore it out to .580.THAT leaves .170 and a wall thickness of .085.If your lucky,the plug might snap off when tightened.I am NOT taking into the equation the DEPTH of the threads.
Back in the late 1960's.the late Tom Dawson and I did a bit of experimenting with the "Nock"chambered breech.The original idea was supposed to speed up ignition and increase velocity by blasting a jet of fire thru the center of the main charge.This idea may have had some merit back when powder varied a lot in quality of performance but our experiments showed no merit with the powders we had which were DuPont and Curtis&Harvey.I made the breech on my 58 like that probably because I could and I enjoy making weird things.
"galamb"is right IMHO.I wouldn't think of using a thin walled barrel without the re-enforcement of the Nock type breech or a bolstered breech on a caplock.
As far as cleaning is concerned,I made a small jag with a screw to twist into the .358 diameter  and it worked fine. I hope this helps.

Bob Roller

[Kermit]

All those percussion breeches seem to point to the sensibility of the eminently sensible and simple underhammer we don't talk about here. The sideslapping muley is similarly smart, but IMcompletelyHO is one of the ugliest things on God's green Earth.

[EdsPlace]

Again, I haven't pulled the breech plug yet, however, my understanding is the breech face has a hole in it 0.195" diameter.  This hole, or "pipe" is between 1/2" and 1.25" long and leads to a chamber wherein the flash hole liner resides.  If true, this appears very strange to me.  On another board, I came across a recommendation to open this 0.195" hole up to 5/16" and cone the vent liner.  The later, I understand.  I do not understand the existence of such a small "pipe" in the breech face.  The primary objection is it gets cloged when swabing the bore.  Thoughts anyone?

[servicerifle]

Hi,I've got a Mortimer.  Ignition was unreliable because of the small diameter of the breech. I bought a section of steel brake line, 3/8" dia. and a 5/16" dia. drill bit. The drill bit has 3 flats milled on it, to fit a 3 jaw chuck. It was a snug slip fit in the brake line, after removing the flare on the line.
I placed the line with the bit in it on a V block and used a1/8"" pin punch to crimp the drill in the line on each of the drill flats.

I removed the barrel and vent.  Chucked the brake line in a variable speed drill and slowly drilled out the breech till just past the vent. Then trimmed off the liner to match the new dia. of the breech.

Since the I've had reliable ignition.

[EdsPlace]

Thank you servicerifle!  This is the information I was looking for.  I'm wondering why you had to put the bit in a brake line;  maybe you don't have a drill press?  Anyhow, was it difficult to remove the breech plug/s?  I have several breech plug wrenches so I'm not particularly worried, however, the Mortimer breech plug appears to be in two pieces on my rifle.  I have not seen anything like this.  There is the first part than has the tang, a center section that has the vent liner, and then the barrel.  My breech plug wrenches will grab the tang, but where will this assembly come apart?  Am I describing what your Mortimer looks like?  Does it come apart easily?  One reason I'm asking all this is because it seems to me it will be easier to fix these issues before shooting the rifle.

[servicerifle]

I didn't remove the breech plug, that's the reason for the brake line. Drilled it out in place.

[EdsPlace]

Wow!  That took some faith!

I'm going to take mine apart and see what I have...

[ranger76]

Take it to the range and shoot it 20 times or more, and then you will know if you need to make any changes. Lorne

[Standing Bear]

First rule of hot rodding, if it ain't broke, don't fix it.

[Steve-In]

I agree with the shooting it first and fix it if there is a problem.  Most production guns have a VERY tight fitting breechplug.  They can be a challenge to get out without buggering up something.    Service method of coming in from the muzzle is probably better until a drill grabs and breaks.  When you look at better English rifles with patent breeches you will see most of the breeches are recessed to allow a slimmer profile.