reaming a barrel

[whitebear]

I bought a new old stock shotgun barrel recently from Numrich Arms it is a .570 inside diameter but the bore is rough never having been reamed.  What would be the best way to ream this barrel at home.  I know that I can send it off to several people and get the job done but I am trying to do as much of my own stuff as possible.

[Metalshaper]

Square bit or "armory" reamer is what you are looking for ( or make yourself )
 you can do a fairly decent reaming job by hand, powering it with a brace drill..

mine was made with a long section of key stock welded to a rod.. and having a length of high carbon
bandsaw blade soldered onto one side..  grind and dress the cutting edge , back it with a slip of
 hardwood and use with plenty of good cutting oil < I used black thread cutting oil ? > increase the cuts
by adding slips of paper between the bit and the wooden slip..

Hope it helps?

Respect Always
Metalshaper/Jonathan

[Angus]

Metal shaper is right. If you check out the Toadhall rifleshop website, Steve has a boring and reaming page that shows a few pictures of the bit. I have helped with this method, and it works!

[James Wilson Everett]

Guys,

Here is one of the armory reamers I use.  It is made from W1 water hardening square stock, fully hardened, but with the connection to the lantern stock tempered.  The lantern stock is brass which attaches to the drive rod.  two corners of the square reamer are sharp and two are rounded.  The backing wood is made from a popsicle stick.  The backing wood and shim will follow with the reamer, you don't need any attachment.  I usually do the first pass with a new shim using a hand brace, but subsequent passes with a variable speed drill on slow (if the visitors are not watching).  Shimming is done with regular paper.  Often when you harden the reamer it will "banana" warp a bit, I lay a sheet of abrasive paper on the top platen surface of my table saw and straighten to "banana" out with a good bit of elbow grease.  Ream the barrel from breech to muzzle using lots of oil.

Jim

[rich pierce]

Jim, I have some questions as I’m getting ready to try to ream a barrel or two. One is 12 ga. What is the minimum and maximum size of the square reamer relative to the bore?

1) If the bore was .710 what is the smallest, wood-backed, lantern stock, square edged steel reamer you’d use? And the largest? Do you try for 3/4ths or so ratio of reamer across the diagonal to bore size?

2) Also what length of the square portion do you recommend?

3) What is the most you would try to ream an original barrel to restore it to decent loading shape without drilling it?

[James Wilson Everett]

Rich,

Great questions!

1.  I try to get as large a reamer as possible to fit in the bore, sometimes I have to round off the back two corners to fit the reamer into the bore, even without the backing strip of wood in place.  I have found that using a small reamer in a large bore that requires a big stack of the wood backing strip/paper shims is not a good idea.  The reamers I have used tend to be so close in the "across the square" measurement that they are difficult to tell apart without a dial caliper.  Really the reamer should almost fit tight in the bore so that the wood backing strip/paper shim stack will be not very thick.

2.  The reamers I use are rather short - about a 4 inch long cutting edge.  I have seen folks use reamers that are a lot longer.

3.  After boring the barrel I use the reamer to smooth the surface finish of the bore, so I only take out a very few thousandths of an inch with the reamer.  This is not a tool to use to remove a lot of metal.

Also, I find the most difficult thing is to harden/temper the reamer without a lot of "banana warping".  One way to control this is to plunge the red hot reamer straight down into the quench liquid without stirring or swirling the part.  When you stir the part as it is quenched the metal will cool one side faster than the opposite side - banana!  I always do seem to get a small bit of warp.  I lay a sheet of abrasive paper on the flat top surface platen and rub the hardened reamer over the abrasive until the warp of removed - this is not a quick job - be patient.

[jerrywh]

I have reamed several shotgun barrels by hand just a Wilson says. I made the square reamers and still have them. Don't matter what the exact size is as long as you can get them in the bore and have enough space to shim it up when it is needed.  It is a lot of work and should be done from the breach end.  Now days they call it back boring. You can buy most standard back bore reamers on line. Except for a 10ga. They are costly.  I made the reamers out of old square files ground smooth. It is almost impossible to find a 10 ga.   I'm going to sell mine soon

[rich pierce]

Jerry, I’m not needing standard sized spiral flute back bore reamers.  I’m refurbishing a ML barrel to whatever size it needs to be to come clean end to end. Hence the wood backed square reamer a la frontier gunsmith.

[Scota4570]

Depending on how rough is rough, you could polish it.  I have done it with a Lewis lead remover and sand paper and a split dowel with sand paper.   Brownells sells shotgun reamers of various sizes. 

[rich pierce]

Ruff

[jerrywh]

Jerry, I’m not needing standard sized spiral flute back bore reamers.  I’m refurbishing a ML barrel to whatever size it needs to be to come clean end to end. Hence the wood backed square reamer a la frontier gunsmith.

  I never used a modern back bore reamer before. All the ones I have are square type and I made them myself.  You know what's hard to find? A 3/4" round rasp or file. Or a square one even harder.
 At least around here.

[rich pierce]

Well if you want to sell soon, keep me in mind.

[jerrywh]

Rich. I will do that

[Carl Young]

"I’m refurbishing a ML barrel to whatever size it needs to be to come clean end to end. - Rich"    ** notes where I go further than just enough to clean up the bore. -Carl

Rich, for whatever it is worth, I use a square "armorer's bit" reamer made from a square file (like Jerry) with a wooden backing, shimmed with typing paper and in the final stages
thinner onion-skin paper (this gives me a mirror-smooth finish, with swarf that is face-powder fine). Reaming from breech to muzzle, once I get a uniformly smooth reamed finish in the entire bore, **I continue to ream but incrementally back down the bore so the end result is a choked bore (larger at breech than at the muzzle) with a mirror finish. Then I proceed to rifle and breech the barrel.

In my younger (strong back, weak mind) days I would do the whole job with a hand brace. Now in my dotage (weak back, weak mind) I switch to a very low speed hand drill when I think the bore is smooth enough that the reamer will not "grab" and scratch the bore. I run a drip of lube (thinned ATF) into the muzzle, which is elevated above the breech. Using a hand brace allows you to develop a feel for how the bit is cutting, whereas the drill is faster/easier but with much less feedback.

Jim Everett's design is much more elegant than my simple reamer, and I may switch to his design if I ever need another reamer.

Regards,
Carl

[shortbarrel]

  I have bored,reamed and rifled many barrels,but no shotgun barrels.The wall thickness ,when this above processes are done is a safety factor.Shot guns have thin walls.