Flash hole location

[Reactor]

I'm building a New England Fowler.  I have found that in order to get good contact with the barrel and the stock at the tang section I had to remove some wood, just enough to close the gap between the barrel and wood.  Seems logical, but there wasn't enough wood to start with and now my flash hole position is going to be .720 inches in front of the breech plug which is .500 inches long.  I moved the lock plate back as far as I could but with this build being a kit, the lock area was already cut out. 
Is this flash hole position too far forward which will lead to ignition problems?

The book I have tells me the flash hole should only be .125 inches in front of the breech plug.

The only solution i can think of is to glue a shim between the barrel and stock.  I have inlet the tang so I would have to put a shim at the end of the tang as well.  Two obvious places that will show the shim.
Any builders have any other solutions?

[RobD]

no matter what, the flash hole should be drilled as close to the breech face as possible.  some will drill the touch hole so close to the breech face that the face needs to be channeled ...

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this need for the touch hole to be close to the breech face is one reason why the patent breech was designed, although this arrangement presents its own set of separate issues.

i don't quite understand what you mean by "my flash hole position is going to be .720 inches in front of the breech plug which is .500 inches long".  all that matters is where the touch hole winds up with regards to the breech plug face.  if this means the touch hole will be about .220" in front of the breech face, that's not ideal and may create inconsistent ignition, but you can probably live with that.  however, if yer saying the touch hole will be .720" in front of the breech face, you've got a real problem that needs fixin'.

[Hank in WV]

Any chance you can post a picture?

[Ohio Joe]

On my last build I intentionally put my flash hole center at .250 (1/4 inch) ahead of the face of my breach plug. I read about this in one of my books (which I now can't find the reference to the reasoning), and on shooting this rifle I can tell no difference in ignition - though I kind'a think the idea is to allow more shots as fouling builds in the breech...

A .720 IMHO sounds rather excessive to me,,, and even my .250 is - in this day and age... However, perhaps back in the day where one may have to shoot a more course powder (like the 1fg / or cannon powder) maybe it's not?

I've shot 1fg with my vent .250 ahead of the breech plug face and have had positive ignition 100% of the time, but this has always been in nice weather conditions.

Are you working from a "kit" build? If so, perhaps you need to talk to the builder of the kit.     

[Winter Hawk]

A picture would help.  3/4" almost sounds like trouble to me, if that is in front of the face of the breach plug.  I am confused.  If the flash hole is too far forward, why would you move the lock back?  But then you talk about shimming and I believe you want to move the whole barrel assembly forward?  Yes, pictures would really help!

~Kees~

[rollingb]

I'm building a New England Fowler.  I have found that in order to get good contact with the barrel and the stock at the tang section I had to remove some wood, just enough to close the gap between the barrel and wood.  Seems logical, but there wasn't enough wood to start with and now my flash hole position is going to be .720 inches in front of the breech plug which is .500 inches long.  I moved the lock plate back as far as I could but with this build being a kit, the lock area was already cut out. 
Is this flash hole position too far forward which will lead to ignition problems?

The book I have tells me the flash hole should only be .125 inches in front of the breech plug.

The only solution i can think of is to glue a shim between the barrel and stock.  I have inlet the tang so I would have to put a shim at the end of the tang as well.  Two obvious places that will show the shim.
Any builders have any other solutions?

The 0.125" mentioned in your book works well with a 1/4" vent liner,.... however, I drill mine a bit further forward, simply because I prefer to use 5/16" liners.   

Welding an extension to the tang and carefully dressing the extension down with a file is a fairly simple fix if the tang isn't tapered. 

Adding a shim to the breech area of the stock in order to move the barrel forward can possibly be done with some careful fitting and staining,... if,... the only wood you have removed is directly behind the breech plug and not on the sides. 

Where did you get that pre-carved stock/kit?

[Reactor]

Sorry for the confusion.  That sentence was poorly written.
The center of the flash pan would put the flash hole .220 inches in front of the breech plug face.
So what I am hearing is that it is not ideal, which I agree, and that some others have this same situation and have no issues with ignition.

This is for a 10 gauge Jim Chambers kit, American walnut stock, octagon to round barrel. 

Being a kit, the lock location was already located in the stock.  I did my best to keep the lock toward the breech but I did not have enough wood to make the flash hole location ideal.

Do you think I can offset the flash hole a few thousands of an inch from the center of the lock pan, moving it toward the breech plug or am I playing with fire?

Do you think I should contact Mr. Chambers and ask his opinion?
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[Reactor]

The single scratched line is the ideal location of the flash hole.  The double scratched line is where the flash pan is telling me to drill the flash hole.

[rollingb]

Sorry for the confusion.  That sentence was poorly written.
The center of the flash pan would put the flash hole .220 inches in front of the breech plug face.
So what I am hearing is that it is not ideal, which I agree, and that some others have this same situation and have no issues with ignition.

This is for a 10 gauge Jim Chambers kit, American walnut stock, octagon to round barrel. 

Being a kit, the lock location was already located in the stock.  I did my best to keep the lock toward the breech but I did not have enough wood to make the flash hole location ideal.

Do you think I can offset the flash hole a few thousands of an inch from the center of the lock pan, moving it toward the breech plug or am I playing with fire?

Do you think I should contact Mr. Chambers and ask his opinion?
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Personally, I wouldn't worry about it,.... I've seen worse things. 
Jim is the expert though. 

[RobD]

.2" in front of the breech face is simply not ideal.  but yes, you should be able to live with it ... unless just idea that it's wrong bugs ya.

however, as rondo alluded to, check if you can push the barrel forward.  this might only mean cutting new barrel stock channel slots for the pipes, shimming the stock where it meets the back of the breech, filling in a bit of the stock's tang channel.  you'd need to insure that the tang bolt and cross lock bolt will all get lined up as well.

[Reactor]

I'm going to see if I can purchase a longer breech plug say .595 inches.  That will put the flash hole at the ideal length in front of the breech plug face.  It a Rice barrel so I'll try there.

[rollingb]

I'm going to see if I can purchase a longer breech plug say .595 inches.  That will put the flash hole at the ideal length in front of the breech plug face.  It a Rice barrel so I'll try there.

Do you have a way to tap the barrel's breech a bit deeper to properly seat a .595 breech plug?

[rollingb]

I just did a little figurin' and if you would go with a 3/8" Chambers WL liner, instead of the small 1/4" liner,..... you would reduce the distance to only 0.035" to the breech face with what you've got.   
(all of which may have been the original intent of the way your "kit" was designed)

Just don't mess up installing a 3/8" liner 'cause I don't think they make a bigger one. 

[RobD]

i don't see how a larger liner would change anything.  the pan would still be where it is, and so would the resulting touch hole.

[rollingb]

i don't see how a larger liner would change anything.  the pan would still be where it is, and so would the resulting touch hole.

You are right, the center of the pan, and the center of the touch hole, would remain (properly) where they are,.... but the outside "coned" edge of the larger vent liner would be moved closer to the breech face. (for best ignition)

All that aside,.... the design problems Reactor is having with the pre-carved "kit" kind'a leads me to believe the gun's design was laid out specifically to accommodate a 3/8" vent liner,..... especially since the kit is a large bore.