slugging a barrel

[Tippet]

I understand I need to drive a slug of lead into the end of the barrel, then get it out and measure it. But how do you guys get the slug out of a revolver's barrel? The frame gets in the way of running a rod through the barrel from the rear.

[RayinNH]

Tippet try the other end of the barrel :). The throats on the cylinder are probably more important...Ray

[mroliver77]

I usually just do throats also but sometimes push one all the way down the barrel. Brett had an ingenious way of pushing them back out and I filed it my "need to know" file in my brain. I cannot remember it now so hopefully brett chimes in.
Jay

[Edubya]

When slugging the cylinder, make dern sure that you've got the cylinder well supported.
You can slug a revolver from breach to muzzle using short pieces of dowel. It does take some time and patience. After I did one, I realized that the cone works as a sizer and if the boolit fit the cylinder it would be automatically sized to the barrel. I make my boolits a snug fit for the cylinder throat and let 'er fly.
EW

[Fugowii]

Dumb questions from me coming!

Why do you have to slug the cylinder throat? Can't you just measure it with a caliper?

[MT Gianni]

A Caliper may not be able to confirm they are round and I am able to use a micrometer on a slug. I trust my mike a lot more than my caliper.

[randyrat]

It's very tough to measure throats with any device i have. I tried i got every measurment under the sun.

[canyon-ghost]

No, they aren't dumb, Fugowi! I just bought a new revolver and don't know enough about them myself. I glad you're asking these questions! Ron

[Tippet]

so wait a minute...you guys are saying I should slug one of the holes in the cylinder instead of the barrel?

[MtGun44]

No, you need to slug ALL the holes in the cylinder AND the barrel.

Read the sticky on Revolver accuracy under the handgun section for more details.

DO NOT use wood dowels, they break and can wedge so tight you won't believe
it. DO lubricate the bore and cyl throat (front) and use soft lead.

Bill

[swheeler]

so wait a minute...you guys are saying I should slug one of the holes in the cylinder instead of the barrel?

You want to slug the barrel and slug all cyl throats. Hopefully you will find that the smallest throat is at groove diameter or just over, what you hope NOT to find is throats that are smaller than groove diameter. That can be fixed too, but adds another step(reaming or lapping) to getting your revolver shooting right.

[swheeler]

MtGun44 you quicker on the draw than me!

[MtGun44]

Two great minds working on the same problem at the same time.


;-)

Bill

[Bass Ackward]

To slug a barrel requires three slugs to be done properly.

1. First into the muzzle and back out. This gives you the bore diameter at the muzzle. Important for older military guns, levers and handguns especially as they are or were cleaned from the muzzle. But you can find new guns that the button was removed poorly during manufacture that will also display a bell shaped bore.

2. Next slug should be of the throat area that can also be expanded to include the throat / forcing cone so that you know what it looks like and what diameter you will need to fill the throat if you can't touch the lands. This can help you determine what bullet designs will perform best in your outfit. The slug goes in from the back and then is driven out from the front so that it accurately displays only that rear area. Handguns often have constrictions in the fame area that must be understood if not corrected.

3. You need a slug pushed clear through the bore as it will identify the smallest diameter of the bore along with any imperfections along the way. You may have constrictions in thin barrels where dove tails were cut into the barrel, or you may have a twist rate variance caused from the barrel stretching when a button was pulled through and it met a hard spot. Often you will have rough spots as the button .... skipped in the bore. You will be able to .... " feel " the smoothness of the bore as a slug glides. If the slug and bore were lubricated, then the push should be smooth and uniform from stem to stern if there are no problems.

Once you have this, you need to construct a picture of your bore. The back should be larger than the muzzle with no constrictions in between or some action will need to be taken to correct the situation. Some very .... poor quality barrels will show descent accuracy at normal cast velocities, but dump on you when you begin to push velocity. You will always need much harder or way soft slugs just to achieve tolerable accuracy than others and you will grasp at theories as to why you are limited until the bore cleans up.

[Tippet]

OK then back to my original question: how to push the slug out the muzzle.

The frame is in the way of using a rod or getting enough pressure onto a series of shorter rods. Hate to use the frame as a fulcrum to lever the the slug through.

[chuckbuster]

I use"Gage Pins" to check cylinder throats. $2.00 each from local industrial tool supply. They have them in .001" increments.

[Bass Ackward]

OK then back to my original question: how to push the slug out the muzzle.

The frame is in the way of using a rod or getting enough pressure onto a series of shorter rods. Hate to use the frame as a fulcrum to lever the the slug through.

Drop a dowl rod in the bore that allows for about 2" of barrel space left after it contacts the back of the frame window. Pound your slug in. Turn your gun upside down and the dowl will drop until it makes contact. Hopefully you left enough to stick out the barrel that will be longer than the bullet. I use a round ball that has enough surface area to measure, but not enough friction to make this difficult. Pushes out with my thumb.


If it doesn't, then you put something through the window of the frame that can allow you to suspend the gun between to points like your knees or the soft jaws of a vise while making good contact with the stick. Then you tap on the block of wood if it simply doesn't push out.

I have a narrow piece of plywood cut for this purpose. Two people can make this less risky for damage. If it is to difficult to push by hand, you can use the vise padding it well with heavy cloth looking for potential problems before you start going with the muzzle up. When you get the hang of it, you can do it by yourself easily. The key is a lubed round ball for the muzzle slug.

[Edubya]

OK then back to my original question: how to push the slug out the muzzle.

The frame is in the way of using a rod or getting enough pressure onto a series of shorter rods. Hate to use the frame as a fulcrum to lever the the slug through.
I'll tell you how I did mine, but some of these fellas have warned you not to use wood dowels.
I did use wooden dowels. I cut the first one just long enough for a piece of bronze scrap, about 0.25 thick and 8-10" long, perpendicular to the barrel fit in behind and held it on one side in my gloved hand. I tapped the shorter side with my mallet. Each following dowel was just a little longer and each piece was cut with my limb shears.
The gun was supported by the padded vise and a block of 2X4 that I had drilled to fit the barrel.
The slug was a cast tape on WW. I cast about 15 of these and used eight for one pistol. It worked so well that I cast 10 of each caliber that I had to do. After the first one, I felt that I really only needed to cast one for each cylinder hole. My pistols are all S&W and I had very near perfectly sized cylinder throats on every one.
Good luck,
EW

[chris in va]

I will add a big +1 to lubing the barrel first. Mine got stuck halfway in, took forever to get it going again even with liberal amounts of PB Blaster. Once it got past that section, three whacks and it was out.

[44man]

To measure near the muzzle of a revolver I use a strong oak board or thick micarta across the recoil plate. It is long enough to allow a grip on each side. Then I drop a brass rod close to bore size down to the wood with the end near where I want to measure. The bore is clean and oiled.
Then I tap in the slug to the brass and with another piece of brass rod from the muzzle, I upset the slug a little with a hammer blow.
The board in the back protects the gun and by putting the muzzle on a padded board on the floor I can push the slug out by gripping both sides of the board and pushing. Sometimes I need to tap on one end as I hold the other to get the slug moving.
It helps to have some help holding things.
I also use two brass rods to upset the slug in the throats, it gives me better measurements. Pure lead round balls work best for me as the area rubbing the bore is smaller and they move easier. They just take a little tap to upset too.
Never upset anything in a revolver without a good tough piece of wood against the recoil plate.
On a double action, take the cylinder and crane out first.
A dowel works pretty good too and if you get stuck, the dowel can be broken off in pieces and removed from the rear so the slug can just be pounded all the way through. So far I have not been stuck.
If you don't upset, the short pieces of dowel work fine. Anyway you do it from the posts here will be fine.
Calipers do not work even for the slug, you need a good mic that reads to .0001".
A small hole ball gage and mic will work for land to land or throat measurements.
Five groove bores can drive you nuts to measure. You can wrap thin shim stock around those slugs, measure and subtract twice the shim thickness to get close enough.
Too bad we all don't own air gauges!