So, how exactly do I "slug" a barrel?

As far as I know it involves jamming a piece of lead through the barrel and measuring the diameter.

I don't want to buy a Ronco Slug- o- Matic.

I have soft lead, hard lead bullets. Fishing weights. The softest lead is probably 22lr. So I could pull several of those and make a large blob (melt them?)

So exactly how do I this? Slugging for Dummies please

You literally push, or drive, a slightly larger than groove diameter soft lead "slug" through the lightly lubricated barrel. You then measure across the widest portion of the slug to determine the groove diameter, and the grooves of the slug to determine bore diameter.

This works if the barrel has an even number of grooves only. If it has an odd number, like Smith & Wessons, you need a special guage block to accurately measure them. For 5 grooves the block needs a 108 degree included angle between the legs of the block.

Is there any other revolver than SW? Well I guess Ruger.

Yes, it would be SW. But how soft is soft for the lead? Do you just hammer it in and then use a dowel to drive it through the forcing cone like a squib?( I saw that done once)

That is pretty much it. Use pure lead if you can get it. I use Hornady swaged round balls. If I were slugging a .32 or some such, I would use a .315 round ball. Old .32s are really .30s and measure about .308, newer ones about .311 so this size ball is good. Take out the cylinder and put the barrel frame in a vice (with lead or plastic guards), plop a ball in the cone, then gently tap it through using a 5-inch hardwood dowel (Or longer, if needed). You will have to work from the other end if it is a solid frame. After the ball is started, it will usually continue fairly easily. Go slow so you can detect rough spots. I measure by rotating the slugged ball in my dial caliper, measuring at several places, and taking the largest value. There may be a better way. I don't use a mike because a dial caliper will measure to .001, which is generally all you need. The .375 ball is the most common size in the .38 ball park, and it is a bit large for .358 bores, but will work. If you want to slug .44s and .45s you can find RBs of appropriate size. Good to have a buddy who is into black powder shooting so you don't have to buy a box of 100.

McShooty said:

plop a ball in the cone.

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Cone? As in forcing cone? or are you dropping it in the muzzle end?

I can not see how it would be possible to push or hammer a slug from the cylinder area as in the way the bullet normally would shoot out the barrel.

I think my fishing weights (egg sinkers are pure lead)

Thanks

Yes, forcing cone, in a top break or tipup. With a solid frame gun you would need to hold the barrel in the vise and work from the muzzle end. If you have a slug of reasonable size and tap gently the slug should move easily as you near the muzzle end. Then you can tap with one hand and catch the slug with your other as it comes out.

Rule3 said:

Cone? As in forcing cone? or are you dropping it in the muzzle end?

I can not see how it would be possible to push or hammer a slug from the cylinder area as in the way the bullet normally would shoot out the barrel.

I think my fishing weights (egg sinkers are pure lead)

Thanks

Click to expand...

Rule 3,

Just like cleaning, if you can do it from the breech then do it, if not then from the muzzle. Once started in the bore a slug can usually be pushed through the bore, doesn't have to be driven all the way.

Soft? The softer the better, pure Lead if possible. Many fishing weights are now Zinc or other "non-toxic" metals. Round ball for muzzle loaders are ideal.

Now, the practical end of all this. If you are wanting to measure a S&W barrel, you can't do it without the proper guage block, so save your time. Instead of trying to measure the slug, see if it will pass freely through the throats of the cylinder, you don't have to know how big it is. If it passes through the throats then they are big enough.

More important for accuracy is bullet fit to the throats, not the bore, that is what the forcing cone does. If the slugs pass through the throats with little or no resistance then slug the throats. The round slug from the throat you cam measure! Once you know the throat diameter you order your bullets from a company which will size to the requested dimension. If you are casting yourself, size your bullets to either the diameter of the throats (or largest one) or .001 larger.

The only real reason to slug your bore is to be sure the throats are at lease that large so the throat doesn't size your bullet under groove diameter. If you want good accuracy, and the slug takes too much pressure to pass through the throats you need to open the throats until the bore slug does pass with only a few ounces pressure. Then go back and slug the throats, etc.

Notice, that while it may be of interest to know the groove diameter of your barrel it is absolutely unnecessary to know this dimension, only that the cylinder throats are as large or larger.

All my revolvers I have to clean from the muzzle end. There is no way to pass a patch let alone a lead slug from the forcing cone through to the muzzle.

I checked some of my sinkers, they are old and soft lead. But as you say it will not do me much good as they are all Smiths.

I'll just check them in the cylinders.

Thanks.

You can get groove diameter in a barrel with odd numbers of grooves/lands by wrapping a thin (0.001"), flexible feeler gauge a little over half way around your measuring slug and subtracting twice the shim thickness from the measurement. It's also possible to accurately measure groove depth with a caliper or comparison to a stack of shims. I agree that the most important measurement is cylinder throat diameter, but there are some occasions where even a good guestimate of bore/groove diameters is useful, especially if the bore turns out to be somewhat nonstandard.

Buck

You can purchase soft lead balls made for the blackpowder shooters. That's what my local gunsmith uses.

Nice!

Alk8944 said:

Rule 3,

Now, the practical end of all this. If you are wanting to measure a S&W barrel, you can't do it without the proper guage block, so save your time. Instead of trying to measure the slug, see if it will pass freely through the throats of the cylinder, you don't have to know how big it is. If it passes through the throats then they are big enough.

More important for accuracy is bullet fit to the throats, not the bore, that is what the forcing cone does. If the slugs pass through the throats with little or no resistance then slug the throats. The round slug from the throat you cam measure! Once you know the throat diameter you order your bullets from a company which will size to the requested dimension. If you are casting yourself, size your bullets to either the diameter of the throats (or largest one) or .001 larger.

The only real reason to slug your bore is to be sure the throats are at lease that large so the throat doesn't size your bullet under groove diameter. If you want good accuracy, and the slug takes too much pressure to pass through the throats you need to open the throats until the bore slug does pass with only a few ounces pressure. Then go back and slug the throats, etc.

Notice, that while it may be of interest to know the groove diameter of your barrel it is absolutely unnecessary to know this dimension, only that the cylinder throats are as large or larger.

Click to expand...

This is the first time I saw someone post that info. Perfect!! It makes total sense.

I thought knowing the barrels groove dia. was a bit much... sort of too much information.

Thanks for posting.

Ss

Rule3 said:

All my revolvers I have to clean from the muzzle end. There is no way to pass a patch let alone a lead slug from the forcing cone through to the muzzle.I checked some of my sinkers, they are old and soft lead. But as you say it will not do me much good as they are all Smiths.

I'll just check them in the cylinders.

Thanks.

Click to expand...

Otis to your rescue!!!

Otis Technology

And I took the more lazy approach to all this. I cast my lead bullets. I then checked the revolver but dropping the bullet into each chamber of the cylinder using a fresh bullet for each one. If I only had to tap them through then they were fine for me. None of mine got stuck enough to need to use the hammer with any serious force. All of my revolvers were .001 over what the bore is "supposed" to be rated for. So I size all my .38 and .357 to .359 and they all work just fine. If by some crazy chance your bullets will drop right through the chamber then your chamber may be over sized. I'm not sure how much the barrel can take in an over sized bullet to match up with too big of a chamber. I look at all this as a step to dive into only if you are getting leading and you have checked for everything else.

I, too, measure the slug after pushing through the chamber.
You would get serious leading if the chamber is undersized. A thousandth or two over wouldn't hurt at all.
I have also used the revolver cylinder to size bullets. Just an experiment. It was slow, but it worked fine.

Maximumbob54 said:

Otis to your rescue!!!

Otis Technology

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Well sure you can clean your (revolvers)guns with the Otis or Bore Snake. They both are useless. No thanks I prefer a cleaning rod and no need to buy proprietary brushes.

Another option is cerrosafe, it's a bismuth alloy and melts at very low temps. like 150deg F. I bought some but haven't gotten around to using it, it's a lot like lead. You can search for more specifics.

Titegroups said:

Another option is cerrosafe, it's a bismuth alloy and melts at very low temps. like 150deg F. I bought some but haven't gotten around to using it, it's a lot like lead. You can search for more specifics.

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Yes, I found that in searching. These lead fishing sinkers I have will work, I can squeeze them easily with a pliers. They are good old deadly lead.
I also have a few rolls of true lead solder I could mash into a ball.

Rule3 said:

Well sure you can clean your (revolvers)guns with the Otis or Bore Snake. They both are useless. No thanks I prefer a cleaning rod and no need to buy proprietary brushes.

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The cleaning patches are proprietary in that they come precut with the holes in them. You can still use any old patch though. I didn't notice a difference in the brush. I thought they were the same old screw in bottoms. I think Rotometals has the chamber casting alloy but not a specific bore slugging alloy.

Casting Bullet Alloys from Rotometals

South Bend brand sinkers were pure lead and may still be.
Use a light oil and a large hammer, 4 lbs or so. I like to put a smaller size of gas check between the sinker and the drive rod.

Maximumbob54 said:

The cleaning patches are proprietary in that they come precut with the holes in them. You can still use any old patch though. I didn't notice a difference in the brush. I thought they were the same old screw in bottoms. I think Rotometals has the chamber casting alloy but not a specific bore slugging alloy.

Casting Bullet Alloys from Rotometals

Click to expand...

RE: Otis
They may well be. Maybe it works great To be honest I have about every cleaning solution and gadget (not the Otis) around. I need to simplify my life. Heck I made my own out of weed eater line. Melted a blob on the end. Great for taking to the range for a quick rifle clean.