FIRST THING TO KNOW: There's a barrel thread change in 1985 on the .22 and .32 Mag single sixes so that's the first thing to be aware of. OM .22 barrels will interchange with NM barrels up to 1984.
New Model Single Six barrel thread change 1986:
OM and pre 1986 NM Single Six .22 barrels, and 1st year 1984 and part of 1985 early.32 barrels are 20 tpi x .557”, shank at forcing cone .430” (earliest .32 I have is # 650-01300, 1st year, 1984 and latest is 650-06801, 1985 with this thread size).
Post 1985 .22 barrels are 24 tpi x .622”, with the old size shank of .430” (lowest I have is #261-18748 from 1986) and .32 barrels are also 24 tpi x .622”, but with shank .486” (lowest I have is 5 1/2”[cut to 4 ¾”] # 650-14117 from late 1985).
REMOVING AND REPLACING BARREL:
1. When removing the 1st time, Ruger barrels are very tight, don’t give up! Colts are not as tight. Make an index mark on top of the barrel and frame (with fine point black indelible ink pen) where the barrel meets the frame. Make your line about 1/32" wide, before removing if the same barrel is to be reinstalled. Soak barrel joint with penetrating oil.
2. You will not tweak/bend a Ruger SA or Colt SA frame with this method, so don't worry about that. Exception: Ruger and Colt .22 aluminum alloy frames!
3. You'll need a 3 ft piece of 2x4 with one end cut the size of the cylinder window.
4. If you don't have a barrel vise, you'll need a very big vise that you can really tighten to about 150 ft lbs. That means very tight!!
5. Take two blocks of oak or other hard wood about 3" x 3" x 3/4" , clamp in a vise and drill a hole a little larger than diameter of the barrel, thru the seam so you have 1/2 of a hole in each block when you separate them.
6. To absolutely guarantee that you don't mar the finish, spiral wrap your barrel in duct tape folded in half the long way so it's sticky on both sides. I DO NOT use rosin as some suggest, it will rub off the bluing when the barrel slips, and it will slip until you have it tight enough in the vise. And you don't find out if the barrel is clamped tight enough until you finally hear the "crack" when it breaks loose instead of slipping.
7.You will need two thick pieces of leather, 1/8" or 3/16", to pad the wood blocks.
8. Clamp the barrel w/blocks & leather making sure there is no pressure on the sight; you can pop it right off when the barrel slips in your blocks, and it will slip until you tighten the vise 3 or 4 more times.
9. Tighten vise until the barrel won't slip in the blocks when you apply pressure on the 2x4. You’ll hear a crack when the barrel finally lets go. I always pre-soak with a good penetrant. A 50/50 mix of acetone and ATF fluid is the absolute best for frozen and/or rusted parts.
10. Reinstalling original barrel:
tighten until both sides of the 1/32” index mark on top of the barrel and frame align. Release pressure and before removing barrel from vise, check to verify that marks still align and that there was no ‘spring back’.
11. Installing a different barrel:
Lubricate barrel threads. Turn in and hand tighten as far as you can, then reverse until the new barrel and sight are straight up and down. Make an index mark on top of the barrel and frame (with fine point black indelible ink pen) where the barrel meets the frame. Make your line about 1/32" wide. Now hand tighten until it won’t tighten any further and see how it 'clocks' (is the sight straight up, right or left of center?) If the barrel hand tightens about 1/8th of a turn short of the sight being at 12 o'clock, you’re good to go, it will turn enough to tighten in the vise so the sight is straight up.
Normally the shoulder of the barrel must be faced off in a lathe if it tightens up more than 1/8” turn before the sight is at 12 o'clock. But if it's close, just a little more than 1/8 turn short, the simplest way to fit it, is to draw file the front of the frame (unless the gun is new, of course, then go to Plan B). Polish and touch up w/OxPho Blue from Brownells or Nu Blue. Use a hair dryer to heat up frame too hot to touch, for each of four coats. The beauty of this method is you won't have to modify the Ejector rod housing length.
To determine how much metal to remove:
The following example is for mid size & most full size Rugers and 3rd gen Colt barrels with 24 TPI (1st and 2nd gen Colts are 20 TPI; you'll need to count the threads per inch of other barrels).
A barrel thread with 24 threads per inch is .0416" of barrel length per thread, one complete turn of the barrel.
PLAN A cont'd:
Let’s say it’s ¼ turn shy of straight up, you need to remove material to get it within 1/8 turn from straight up. A 1/8 turn is 1/8 of .0416" or .0052", it must be’ faced off’ from the barrel shoulder in a lathe.
Next measure how far the barrel sticks thru the frame and add the .0052" to it because once you cut the shoulder or draw file the frame the barrel still stick thru that much farther. Now compare that measurement to the new cyl-to-frame spacing and you'll know what the b/c gap will be. If the barrel is too long and B/C gap is too tight or no gap you'll know how much to take off of the barrel forcing cone shooting for about a .005" + or - B/C gap. If the barrel is not long enough to get that tight of a gap or something close to it, you have to go to PLAN B.
If the barrel throat is too short (barrel/cyl gap excessive) or the barrel doesn't hand tighten until the sight goes past 12 o'clock you'll need to ‘face off’ enough metal from the barrel shoulder to turn barrel almost another revolution. For example if the barrel doesn't tighten until it's 1/4 turn past 12 o'clock, the barrel will have to turn in another 3/4s of a turn for the sight to come around again and be straight up when barrel is tightened. So (.0416" divided by 4) x 3 = .0312" has to come off the barrel shoulder.
You’ll need a lathe to 'face off' .0312" of the barrel shoulder where it meets the frame. And you'll have to shorten the ERH the same amount. I make a brass or aluminum pilot of barrel groove diameter to drive in the muzzle to chuck up the barrel in the lathe.
(Note: if the barrel tightens up just a tiny amount past 12 o’clock, there’s a short cut; gently tap the sharp edges of the last two rows of the barrel thread. This will create a slight “interference fit” of the threads causing the barrel to tighten at 12 o’clock).
Install new barrel per #10 above.
12. Don't get in a hurry.
TWEAKING BARRELS TO ZERO:
I have tweaked many barrels to get them to shoot to point of aim and changed Colt and Ruger barrels. My experience: the hardest thing to do is to move a barrel just a slight amount, especially tighter! So turn the barrel out loose and then retighten it to the new position you want.
Before you attempt to 'tweak' the barrel, to change windage or straighten up a front sight, be sure that the sight isn’t just leaning to one side. If the front sight is crooked because the sight base wasn't soldered on square to the barrel, even after you straighten it by turning the barrel, it still won't look right! The blade may be straight up but the base could be off center on the barrel.
SWAPPING A CYL AND/OR BARREL:
I don't see the timing of the new cylinder as an issue, at least not in my experience. 1st thing to eliminate. Check the cyl timing in the new gun. Turn off the old barrel if the cyl won't fit because of the barrel extension thru the frame. Assuming the timing works out for the cyl measure the space between the front of the cyl and the inside of the frame surface and write it down. Remove cylinder. In the remote chance the cyl doesn't time, a few strokes on the cyl pawl or stretching it a bit is quite simple but we don't need to cross that bridge right now.
Turn in and tighten the new barrel and see how it 'clocks' (is the sight straight up and down?) If it tightens up before the sight is at 12 o'clock but it's close, the simplest way to fit it is too draw file the front of the frame. The beauty of this is you won't have to modify the Ejector rod housing length.
The barrel thread is 24 threads per inch or .0416" per thread or one complete turn of the barrel. So for example if the barrel is about 1/8th of a turn short of the sight being at 12 o'clock you need to remove 1/8 of .0416" or .0052" from the front of the frame which is not much.
Since .0416 is one turn, the most you'd have to remove is less than that, worst case scenario, so there's not a lot to remove. For those with a surface grinder or milling machine that's the professional way. A belt sander used with skill can work for the rough cut.
The rest of us use "draw filing" to get most of it off, followed by sanding with 400 grit paper until perfectly flat and square. Then finer grits until you match the rest of the guns surface, usually between 800 and 1000. Place frame in a vice perfectly leveled, sanding with a perfectly flat surfaced aluminum or steel sanding block. Then cold blue with Brownells OxPho Blue bluing cream. The front frame surface is protected well so wearing off the cold blue is near impossible.
Next measure how far the barrel sticks thru the frame and add .0052" to it because once you draw file the frame the barrel still stick thru that much farther. Now compare that measurement to the cyl spacing from above and you'll know what the b/c gap will be. If it's too long or too tight of a gap you'll know how much to take off of the barrel forcing cone shooting for about a .005" + or - b/c gap. If the barrel is not long enough to get that gap or something close to it, you have to go to Plan B.
If the barrel is too short or the barrel doesn't tighten until the sight goes past 12 o'clock you'll need to take more off the front of the frame. For example if the barrel doesn't tighten until it's 1/4 turn past 12 o'clock it'll have to turn in another 3/4s of a turn for the sight to come around and be straight up again. So (.0416" divided by 4) x 3 = .0312" has to come off the front of the frame. The beauty of this is you won't have to modify the Ejector rod housing length.
If you have a lathe you can 'turn off' .0312" of the barrel shoulder where it meets the frame. But again you'll have to shorten the ERH.
Bottom line is you need some measurements to see how the parts will fit together and what you need to do, simple as that.
If you’re going to cut the barrel off shorter than the ERH screw hole it becomes much simpler, but you'll have to drill and tap a blind hole for the ERH screw when all done and shorten the ERH. If you're shortening the barrel to the standard 4 5/8" you just order a new front sight blade and have someone mill and solder it in place and re-blue the gun.
I would not try to salvage the front blade from the old Vaquero or Colt barrel. They are only $6 from Brownell's and if you want to sell the original barrel most will pass on it because it'll need a new sight soldered in and the barrel re-blued.
It's a lot simpler to do than to write it up but I tried to cover all situations so you have the background.
Hope this helps,
Fabulous detail from Hondo44.... been meaning to post a "THANKS". I may never try a barrel change, but I printed and have read through it twice. Many thanks for taking all that time to give us all that info Hondo44.