First gun... Day one... question.

[Jeff Durnell]

I won't have any real time to dedicate to gun making until after the new year, but wanted to get the barrel into my Chambers precarve because it seems like it would be easy enough and a safer way to keep it. And after looking at my buddy's guns Saturday, I just kind of wanted to get started. Lol. So this morning I got the breech area of the stock squared up and finessed the stock until the barrel drops in with just a little thumb pressure.

As is, it appears the pan and touch hole would be lined up just in front of the end of the breech plug, but when viewed from the other side, it looks like, according to the bolt location in the brass side plate, that the rear lock bolt won't go through the breech plug 'lug' or whatever it's called. It'll be about a half hole into it... drilled or filed into its edge. My question is, am I right to think I should move the barrel rearward in this case by continuing to remove wood from the stock in the breech area? I think if I do, if I remove 1/8" to 3/16" of wood, the bolt hole will be better housed within the plug and the touch hole center would be about 1/4" in front of the face of the breech plug. Complete virgin on day one here. Any thoughts or ideas are appreciated.

[Jeff Durnell]

[Jeff Durnell]

[smart dog]

Hi,
This is no big deal.  If the bolster of the plug has not been inlet, you can file down the back of it to allow clearance for the bolt.  If it is already inlet as is, then simply file a notch for the bolt in the back of the bolster. The most important thing is to make sure your vent hole has plenty of clearance in front of the plug.  Ideally, the rear lock bolt should be located completely behind the bolster but that is often not the case.  A word of caution, file the notch deeper than the bolt so the bolt actually clears the notch without touching. Do not make the bolt fit tightly behind the plug because during recoil, the bolt may act as a jackhammer on your stock at a very weak point. A couple thousands of an inch clearance will prevent that.  One downside of having to notching the bolster is that the bolt likely needs to be removed to remove the barrel from the stock.  No big deal but I must confess that I have a gun with that feature and I routinely forget to remove the bolt and then wonder for a few minutes why the barrel does not come out.  Then I remember the hole or notch in the bolster and I remove the bolt. No matter how many times I remove that barrel, I still forget about half the time.

dave   

[galudwig]

There is no advantage to having the rear lock bolt set entirely within the breech plug lug. If the bolt wants to fall half on/ half off the lug, that is no problem. Just mark the spot and file a notch to allow the bolt to pass through. The rear lock bolt is designed to hold the lock in place, not prevent the barrel from moving backwards.  Ideally, the bolt hole that passes through the lug should be larger than the bolt itself so that there is no binding. It is vitally important to make sure that the breech end of the barrel is firmly contacting the shoulder, or the back end of the barrel channel. A tight barrel inlet at that spot will improve accuracy and prevent the barrel from moving backwards under recoil.



Regarding the touch hole placement, general rule of thumb is to have the actual hole as close to the breech face as possible. Some guys simply drill a 1/16" hole into the barrel up against the breech face and get good results. If them miss by a bit, they simply notch the breech face to allow the heat from the prime to reach the main charge. If you are going to use touch hole liner (e.g. Chambers White Lightning; highly recommended), you will want have the actual hole fall approximately 3/16" to 1/8" in front of the breech face (for 1/4" and 5/16" liners). That will allow you room to install the liner without drilling into the breech plug and threads. I routinely set my touch holes 1/8" in front of the breech face. Regardless of what you do, lay out where you want the touch hole to be before you start your lock inlet. Where the pan lays in relation to the touch hole is important and it is easier plan for the right place up front than having to "fix" it later.

As a beginner, I recommend you buy and reference three books: "Recreating the American Longrifle" by Wm. Buchele/Geo. Shumway, "the Art of Building the Pennsylvania Longrifle" by Chuck Dixon, and "The Gunsmith of Greenville County" by Pete Alexander.  Tons of good info and all three and they make great Christmas presents!

[Jeff Durnell]

Exactly the info I was looking for. Thanks guys. I still need to get some marking ink and seat the barrel really well against the stock in the breech area, but I'm close... and glad I don't have to move it backwards any real distance. I understand what you said about the bolt - lug clearance,  touch hole, breech plug face, and pan orientation and will pay especially close attention to them.

So much to consider simultaneously, but fun!

[oldtravler61]

  galudwig looking at your breech plug picture. How strong is that bolt hole in the plug with only 3/4 contact for the bolt?  Just curious about it's strength.
Of the few guns I have made I have always had solid metal around the bolt hole. .   Oldtravler

[galudwig]

  galudwig looking at your breech plug picture. How strong is that bolt hole in the plug with only 3/4 contact for the bolt?  Just curious about it's strength.
Of the few guns I have made I have always had solid metal around the bolt hole. .   Oldtravler

I'm guessing the integrity of the bolster hasn't been compromised in any way. The only purpose for the hole is to allow the lock bolt to pass through the bolster anyway and since the hole isn't supporting anything, I'd say strength is not an issue. The bolster itself sits tight in its notch and the back of the barrel is tight against the shoulder, and that is what is most important to me.

I don't see the notch as an issue when the hole falls close to the back side of the bolster. On the other hand, I wouldn't use a notch on a bolster for a hole that fell real close to the back of the barrel. I think that could weaken the bolster. I have a couple rifles with bolsters drilled that have metal all around the hole just like yours. However, this one and another rifle had the holes line up right near the back of the bolster. I too thought you had to have metal all around the hole until my instructor at the time (JK) recommended the notch as something used on original guns. The bolster on my Allen Martin Schimmel is notched in a similar manner as well.   

I also have never had any issue removing notched bolsters from any of my barrels.  They come out just as slick as an intact one using one of Rice's plug removal tools. 

[elkhorne]

Jeff,
Suggest you purchase the DVD of Jim Turpin assembling one of Jim Chamber's rifles and he discusses moving the barrel back. Did one of these rifles in a class and was not instructed to move the barrel back. This resulted in having to drill into the breechplug to install the touchhole liner and then cone the face of the breechplug to accommodate the liner. Hope this helps and remember don't just rush ahead. Study and do all the steps intentionally and you will come out with a rifle you can be proud of.
Good luck.
elkhorne

[Jeff Durnell]

Thanks Elkhorne. I do have the Turpin DVD on building a Chambers gun and will watch it again.

I was looking at an original barrel last week and it had almost a half of a hole filed into the back edge of the plug for lock bolt clearance.

You're right, I need to go slow, study, and really think things through before I make any drastic moves.

[Lucky R A]

         If you haven't already you should determine the exact style of gun and builder you are emulating.  Then find out the breech plug length and how it is terminated.   Breech plug tangs as received are usually over length to allow them to be styled.   Tang terminations can be anything from straight to a point.  Most were some form of a thumbnail termination.   It is better to get it right now than to wish you had later...go slow, study and enjoy the ride....Ron

[Eric Krewson]

Locate the position of the face of your breech plug and mock up where the touch hole should be and see how that fits with your precarve. I got into the breech plug on my first build and was determined not to do that again, especially after I spent a long time fitting the breechplug to have a very tight seal. Having to notch the breech plug did away with all that plug fitting.

I use a circle template for a 5/16 hole for my future White Lightning liner and draw the circle centered on the flat to be slightly ahead of my breech plug.



I usually end up with something like this on my lock bolt hole through the tang, plenty of bolt clearance, nothing touching.

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Of course you want a perfect fit on the back of your barrel to inlet before you do any mock-up.

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