Breeching a barrel

[KY Shinner]

I think I have died and gone to heaven.  I am a new member and have read a lot of the posts on here the last couple of days.  Must have answered a dozen or more questions that I had.  Looking forward to pestering you guys.  Thank You

My question:
      I inherited two Colerain barrels both of which have no breech plugs. (45cal b weight and 50cal c weight both 44"long)   I have seen breech plugs at different events that I have attended but I would think this fit is down to a thousandth of a inch.  Is it possible to breech a barrel without a full blown machine shop,or should they be sent back to Colerain.

[rich pierce]

Many a barrel has been well breeched using simple tools and approaches.  Find out the diameter and pitch of the breech threads and the depth of the threaded portion of the barrel and get a plug that is long enough. It helps to have a nut that fits the threads of the plug.  To get a great fit you can work the plug, the barrel, or both but most folks choose to accept the depth of the threads in the barrel and focus on the plug.

You know what you want- the tang snug against the barrel on the flat opposite the maker's mark and the face of the plug tight against the breech face at the same instant.  Getting there is just a matter of doing a little figuring and going slowly and carefully.

Measure the depth of breech and plug one more time, then color the face and threads of the plug with a felt marker.  Turn it in by hand, then snug it in with a wrench with little force, and see how much gap you have between barrel and tang. Knowing the pitch tells you how much each complete turn moves the plug inward.  So a pitch of 16 would draw it in 1/16" with a complete turn, and 1/8th of that per single flat on an octagonal barrel.  More or less 0.004 per flat.

By examining how the marker wore off the breech plug threads, you can see what's up with the fit of plug to breech.  You'll have to decide whether you need to get and use a bottoming tap to get fuller threads near the breech face.

Now it's a matter of deciding where  and how much to remove.  Generally you want to keep the barrel maker marks on the bottom flat.  But if they are not deep or important to you, don't hesitate to draw file them off.  If you have a nut that fits the breechplug, this helps keep things square as you cut or file the breech plug face to get it to turn in further.  Take off about 0.010 less than what you need from the face of the plug and then fit by hand, marking the plug face each time, looking for where it gets rubbed off, and looking for marker transferred to the breech face.

Generally it's necessary to file down the front thread of the plug a tad because getting a fill thread all the way to the face of the breech is not readily accomplished.

[northmn]

The barrels sold by Coleraine that I see listed that do not come with breech plugs are the Oct to Round that have 3/4 X16 by .55 plug requirements.  As I have been making my own plugs for years but have little to add to Rich's Advice for a premade plug.  TOW used to sell the Coleraine plugs.  If you use a bolt you square the face as Rich suggested.  I use a inletting black or Prussion blue to make sure it bottoms.  Mark the bolt with a marker and remove it. I then start cutting the bolt off leaving about 1/2 inch or so sticking out the breech.  Cut to form a flat that is a little smaller than the width of the flats for a wrench to fit on.  A nut helps hold things.  File off the threads where the tang fits and cut a couple of Vs in the top to hold weld.  I keep a length of 1/4X1/2 flat stock for tangs and cut off what is needed for length and weld the flat stock to the bolt.  To do so I put the bolt back in the breech after it has been cut with flats to fit the wrench.  You can then butt the flat stock up against the breech (it does not hurt to slightly bevel the face of the tang that fits against the breech)  Weld the back part, remove the plug, put on the nut and weld the sides.  I have done this with a little 115 V buzz box and 7014 rod.  I prefer my 220 stick welder, but really like the smoother 7014.  Most use wire feed now days but I learned on a stick welder and have one in my shop and have no need to buy another welder.  6011 splatter a bit but also give a good deep penetration.  I does not hurt to clamp the welded part when bending to fit the wrist profile or prebending the flat.  File and grind things to profile.  I can do this pretty quickly.   We did this in the old Douglas barrel days as you HAD to put the makers name up or down.  It seemed easier than fitting a prebought plug.
Almost all barrels use NF thread in 9/16 for small bores, 5/8 for medium bores and 3/4 X16 for large bores.  12 ga shotguns and really big bore use 7/8X14.  Most use a "square" breech of equal depth to diameter.  Older original ML's used a shorter plug like Coleraines .55.  Makes for better geometry on a finished gun.

DP

[Roger Fisher]

If you do not trust yourself to do it - don't!

If the barrel maker can and would do it ship 'em back - you will sleep bettter!

There is a  good reason why Getz breeches his barrels!

[rich pierce]

I have never seen a Getz barrel poorly breeched and don't even bother to check anymore.  I don't trust breeching by other barrel makers and always remove the plug, inspect and make changes as needed.  I'd prefer to do it myself to getting one that does not butt up against the face, necessitating a full turn of the threads sometimes to get it indexed right and a good seal.  The last thing you want is fouling and erosion getting into your breech threads.

I have a rifle I breeched by hand in 1978 and though I don't shoot near as much as Roger, I unbreeched it last year for a look-see and the threads were as shiny and perfect as the day it got breeched.

[KY Shinner]

Thanks guys for the input.  I think the nut to keep the plug square is a great idea.  While I do not work for a machine shop, in my business I deal a lot with them and measure down to very small tolerances.  Roger...trust me if it doesn't look right I will send them to the manufacture to have them do it.

Thanks Again
Ed

[Dphariss]

I think I have died and gone to heaven.  I am a new member and have read a lot of the posts on here the last couple of days.  Must have answered a dozen or more questions that I had.  Looking forward to pestering you guys.  Thank You

My question:
      I inherited two Colerain barrels both of which have no breech plugs. (45cal b weight and 50cal c weight both 44"long)   I have seen breech plugs at different events that I have attended but I would think this fit is down to a thousandth of a inch.  Is it possible to breech a barrel without a full blown machine shop,or should they be sent back to Colerain.

I suspect there will be some protests over the following but this is how I was told it needs to be done to be RIGHT. Many guns out there are not breeched in this manner and give good service. But I like it "perfect". If people disagree with anything stated here so be it. I am not forcing anyone to do things properly just giving MY OPINION.
Modern thread "tolerance" requires a seal on a shoulder to prevent the threads from becoming fouling traps. When used with some of the perchlorate "replica" powders fouling traps can lead to serious corrosion issues that can effect safety.

Barrels can be perfectly breeched with a magic marker, a small 90 degree square, vernier, dial or electronic caliper, a 12" adjustable wrench and a couple of files. A 10-12" mill and a 4-6" of some sort.
Since you have a 45 and 50 I will assume (hope for) a 5/8" x 18 or larger plug.

NOTE.
Many store bought plugs have a significant rebate at the tang end of the threads. Make sure that in fixing the thread depth at 5/8" that the beech plug will have 1/2" of threads when shortened to 5/8". If not adjust the barrel depth accordingly or get a better plug.

If 5/8" you will have a shoulder, significant in the 45 and less in the 50, that the face of the plug must seat against if the threads are to be sealed.
This seals the threads and eliminates any fouling/oil traps that can cause problems. While its possible to use a 9/16 plug in a 50 its not a good idea IMO.
You need to measure the depth of the threaded hole in the barrel. It need not be greater than 5/8" deep and should not be less than 1/2". If over 5/8" carefully file the breech till you have 5/8" (.625")or slightly less.  Check to see how deep the hole is threaded.


Make sure you file the breech flat. Best if you can walk around it as you file and check it with the square. Tapered or swamped barrels take a little thinking when using the square. Basically when the square is flat on the beech the blade of the square should have the same gap at each flat. Straight barrels are not a problem.
Once the depth is correct shorten the plug till its about .010"-.015" longer from the face of the tang that contacts the end of the barrel to the face of the threaded portion that seals the bore.
Paint the face of the plug and the first 2 threads with a black or blue magic marker and try the plug in the barrel to see how deep it will turn in. Chances are it stops about .09-.1" from where you want it. This is the threads of the plug running into the unthreaded portion of the hole. This is *finger tight* or very light wrench pressure to mark the "ink". If you damage the threads by turning the plug in too tight at this stage it will enlarge/deform ALL the barrel threads as it is removed. So make sure you have clearance for the front thread to prevent this.
If you have one you may grind a tap to a near absolute bottoming tap and thread the hole another thread or 2 closer to the bore. DO NOT TAP TOO DEEP just another turn usually. Too deep will have the tap cutting notches in the "shoulder" if there is one.

Now the fitting starts. You will have to file the first thread of the plug back about 1/2 turn. Hit with the magic marker again and re-try. It should go in a 1/2 turn farther than it did. As you continue the face of the plug will contact the bottom of the hole before the tang seats on the barrel. Assuming good measurements.
Now carefully shorten the  face of the plug using the magic marker to tell where to file.
This is a plug being made for a 50 caliber smooth barrel. In a rifled barrel you will see some lands at the face as you come to the end of the bore.


Keep fitting the face of the breech and the end of the barrel until the face seals the bore and the tang is tight on the breech.
Final polish on the breech face should be 320-400 grit.
When tight and the tang aligned with the top flat the plug should be moderately tight.
But you need to work into this. Oil the threads and tang with something like STP and work the plug back and forth as it will tend to turn a little farther each time as everything "crush" fits. If done right the breech can be installed and removed without fear of turning it a little too far on reinstallation and its being loose.  It should be reasonably tight with the 12" wrench but not a strain to install or remove when done. Ideally it will turn up to the top flat with moderate force and then stop as everything mates and the torque to move it farther greatly increases.

Hopefully this is fairly complete. Something came up and I was away for a couple of hours after starting and my train of thought kinda jumped the tracks.

Dan

[David Rase]

Before I acquired my lathe I fit many a breech plug with only a square, a flat file and a Marks a Lot black marker.  Cut and crowned quite a few barrels by hand also.  I just helped a friend breech a barrel a few weeks ago that he brought over.  I was going to chuck it into my lathe but the plug and barrel fit were so close it was faster to do it by hand.
DMR

[Dphariss]

Forgot...
Proof the barrel before putting it into service.
Dan

[Steve Bookout]

Hi Northman!  Your description is exactly what I am doing to two old Dixie octagon to round, .410 trade gun barrels at the instant.  Glad you shared the method with the craft.  Cheers, Bookie

[Dale Halterman]

Generally you want to keep the barrel maker marks on the bottom flat.  But if they are not deep or important to you, don't hesitate to draw file them off.

If you do decide to remove the maker's stamps, remember that they are stamps and metal was displaced, not removed when they were stamped. I did a Green Mountain barrel and used a small ball pein hammer to level out the area where the stamps were. This displaced metal back into the vallies and required less filing to get a good surface.

Dale H

[RobertS]

I'm a newbie, too, and about to make my first attempt at breeching a barrel.  I think this is much more informative that what I've read in any of the popular gunbuilding books, and my opinion is that this would be a great thread to move to the tutorial section.  This site is the best around, and I appreciate that so many knowledgable people are willing to freely share this information with the rest of us.  THANKS!