breech plug fence frustration

[ddoyle]

I am trying to sort this issue for the second or third time. It gets put away and taken out every couple months(gun building must have been more fun before calipres  ) Two issues kind of intertwined I figure.

I want a large siler's fence to line up with the end of the barrel.

The 3/4 breech plug is .451 long with 5 threads. There is approx .05 barrel hanging out behind the end of the breech plug threads. (that distance at the end of the barrel has no engagement between plug and barrel i.e concave empty space (another aggravation))

If I line the fence up with the end of the barrel and drill for a vent liner and relieve the plug so the vent can see the powder I will end up with only 3 or maybe 4 engaged threads.  

Are three threads enough?

Just move the lock forward and be aggravated by it?  Add material to the back of the fence to make up the space?




 

[Mike Brooks]

How could it possibly make any difference where the fence is?

[Boompa]

I'm confused. How about a photo?

[Ron Scott]

Having the fence line up with the breech is not an issue if you do a reveiw of original flintlocks. This is particularly true if you examine Flintlocks of Germanic Origin. The handful of original Flintlocks that I own have an average space of 3/16 inch between the fence and breech. This typical lock placement gives latitude to drill the vent without interference with the breech face.

[Keb]

Shorten the breech end or don't use the Siler lock. Some of Chambers other locks have the pan far enough forward to line up with the end of the breech very nicely.
I've always tried to get the fence to line up with the end of the barrel but I was immediately told it wasn't necessary or typically done in the past. Maybe, maybe not but it sure looks a whole lot better than having that lock so far forward, in my and some other maker's opinions.

[jerrywh]

 Must see a photo.
 Relieving the lug for the liner or vent does not mean you have less threads except for the area of the vent relief. Do you really think the plug will turn sideways and come out? I don't think so.
 For the plug to turn sideways the barrel would have to fail. You cannot compress a solid. If the barrel were to fail that is the most unlikely spot with the least pressure on it.
  Shoe photo.

[smart dog]

Hi DDoyle,
I urge you not to worry about lining up the fence with the end of the barrel and don't notch the plug.  I have some experience with that during my early days and it led to frequent misfires and was difficult to keep clean while shooting and cleaning up afterwards. I eventually cupped the entire face of the plug and that helped with the misfires but I had to make a cleaning jag with a rounded face to get into the breech for cleaning.

dave

[ddoyle]

Thanks guys.  Appreciate the input.  Pretty cool how many centuries of experience are on tap at ALR.

I am trying to give up the fence lining up idea and getting the notched plug idea off the options list has really helped. 

 Mike,I just figured not having a cavity behind the fence looked better and would preclude stuff fetching up, thought it was what was aimed for when possible. Seems every interface of wood and metal on a long rifle/fowler is designed to direct water away from the lock/barrel channel so to my inexperienced eye having an unfeathered notch there just contrasts with the flow and shape of everything else. Just a notion I got about what I thought was ideal. (you know us post 1960 kids we like everything to fit together like lego/tinker toys  )

 jerry no I did not figure the plug would twist out or blow out catastrophically, just wondered if three threads would be considered acceptable for long term gas sealing. Myself I was guessing that three would be fine if there was a gas sealing shoulder ahead of them but in absence of that shoulder was concerned.

If I could be so bold, would anyone have an LR queen anne lock or a TOW catalog on their desk that they could measure from the center of the pan to the back of the fence. (left handed so options are bit more limited).

Now I am thinking this barrel might have been born to serve a right hander......

[jerrywh]

 I agree with smartdog 50%. I think it is a good idea to cup out the breech plug but I see nothing wrong with notching the side of the plug. In fact I think it's good if done correctly. I'm not saying Smartdog is wrong in his method. I just don't see any big disadvantage in one way or another.
   Question--- How do you clean a gun with a patent breech?  It is explained in the Manton book.
 Cleaning a flint breech with a notched plug is much easier than that although the patent breech is very popular with many who dislike the notched plug. Go figuer

[ddoyle]

50% agreement is pretty good

this one looks nice, wonder why any one would want the fence to line up?

[Jim Kibler]

In terms of effect on a gun's appearance, having the fence line up with the back of the barrel would be about 99th on the list.  There are so many more important aspects to consider.   

Sometimes, I've seen people concerned with aspects such as this when major aspects of stock design are completely off. 

So, my advice is not to worry about it.

Jim

[Dave R]

There have been many guns built back in the day as well as contemporary guns with notched breech plugs  however I have found out thru practical shooting experience  that powder residue builds up in the cupped area on the face of the breeechplug due to touch hole too far back requiring notching of the breach plug so powder can find it's way to the touch hole / liner and attributes to excessive residue buildup and increases misfires!Especially in high moisture conditions.

Don't worry where the fence is placed it looks nice at the back of the barrel  however there are many more things to consider.

I have just opened a can of WORMS!

[ddoyle]

Chisel in hand going to inlet this bolster so the pan centers forward enough of the plug to allow a vent  and pretend I never hear of fences or alignment.

Thanks again I appreciate you all humoring me on this.

Cheers

[EC121]

You could remove the threadless part of the breech and refit the plug.  A bit of extra work but no loss of threads, and it would allow you to move the lock a bit closer to breech end and remove the cupped area.. 

[Mike Brooks]

If my fence lines up with the back of the barrel it's purely by chance. I have never paid any attention to it.

[Herb]

The Queen Anne lock measures .700 from center of the pan to the back of the fence.  The large Siler measures about .45 inch, same as the Chambers Deluxe Siler.  For a tutorial on how to fit a breech plug, see Tutorials, Metal Shaping, my post "Fitting a Hawken Breech Plug By Hand" July 7, 2010.  Of course, it works for any breech plug.