View Full Version : Slugging a barrel

07-19-2006, 11:44 AM
Hi there...I have been lurking behind the firing line here for a couple of weeks, and I am finding quite a bit of helpful information. I have a question here that someone may have have had experience with .
I have a muzzle loading over/under that was my Great Granddad's. It was build back about 1875. My Dad and my brother and I have all killed game with it, from ducks to deer. It hasn't been shot in years and I'd like to use it again this hunting season, while I am still able. I want to cast some bullets, but I am not sure of the exact bore of the Rifle barrel. It is close to a .38, and the shotgun bbl is close to a 16 Ga. I'd like to slug the bbl, but the breech plug cannot be removed. We tried back in the late '50's when we "Restored" the gun, and we were all afraid of ruining the gun because the plug was frozen. Yeah I know...no one ever restores a old gun because it loses value. Well I hope this gun is never sold, and just keeps being handed down. We restored it it to keep it functional and keep the appearance looking good.
Anyway, I have thought about slugging it only a few inches and removing the slug with a long drywall screw, and then mikeing the slug. Up until now we shot balls in it, but I'd like to try a cast bullet to see if I could improve the accuracy. Any thoughts on this?

07-19-2006, 10:57 PM
One thing you could try is a Cerrosafe casting (Cerrosafe is available from Brownells). I think you could do this in the same fashion as a LBT lapping skag. The instructions for the skag are as follows (just use Cerrosafe instead of pure lead). Cerrosafe is commonly used to check bore, chamber, and throat measurements.

"Form a dam inside the bore about 1 1/2" from the muzzle with paper towel, tamped smooth as practical. Insert a roughened rod end, centered as well as possible. Pour in molten pure lead. Remove skag from bore. ... I place a small charge of powder before installing the paper casting dam, then when done casting the lap, ram the dam down to the powder and shoot it out. "

Make sure you follow the Cerrosafe instructions closely. The time at which you check the diameter (1 hour after solidification if memory serves) is crucial.


07-19-2006, 11:40 PM
Thanks Rugerfan for the hint...I had thought of the cerro safe, actually I was thinking of Woods metal, but cerro safe should do better. I got brave this evening and drove a slug down in the muzzle end of the bbl and used a long drywall screw to retreive it. It miked to .410. If this is fairly close, I was thinking of a sized CB between .406, and .409.....Does this sound about right? If so I need to beg, borrow, or steal a few pills from a caster before investing in moulds.
Does all this sound logical.....

07-20-2006, 12:35 AM
Now you're getting a little outside of my personal experience. Hopefully someone with knowledge on the subject will chime in. I'm guessing you need some sort of hollow-base minie.

Sounds like a very interested smokepole. Can you post a pic?

07-20-2006, 09:47 AM
You can also do it just as you originally posted. Tap an oversize slug down the bore and put the screw (or ball puller, which you should have) in and bring it out. I find this works even better than pushing the slug all the way through with the plug removed. It expands the slug to closer to true groove diameter. I find the mesurements to run @ .0005 over the full length reading with this method. I'd go on down a ways on an origianl as the bore is often worn from loading, but it's usually the rifling lands and not so much the grooves. Better to cast a ball slightly oversize anyway IME, for accuracy. Get a mold @ .010 under groove dia. & start with .020" patching.

07-20-2006, 11:42 AM
To slug a m/l barrel, I use an oversize slug with a hole through the center and put it 2-3" down a well-lubed barrel. The hole makes it much easier to get the screw (or ball puller) to bite. Years ago, the first time I tried it, I made the mistake of driving an undrilled slug way down and the ball puller pulled out of the fully obturated slug. (They work great for a normally sized ball or slug, but they are not designed with the the added friction of the bore slug in mind. Live and learn.) I had to have a friend weld a screw onto a metal rod to get it out of there, and I do not recommend going that route. [smilie=1: The idea of putting a little powder in first just in case is a brilliant one - wish I'd have thought of it back then. You can get a good idea of the size needed by slugging up near the muzzle.

If when seating a patch and ball it gets suddenly easier as it goes in, then you know that it's tighter near the muzzle. This won't cause any problems with soft lead as they bump up and fill the grooves on firing. If the opposite is true, you should think about a hollow based boolit like a minnie with a skirt that can expand. Just try every combination of patch/ball, boolit/lube that comes near to fitting and see what shoots best. .41mag boolits cast of pure lead may work well lubed with liquid alox unpatched, certainly cheaper as an experiment than having a custom mould made.

07-20-2006, 11:53 AM
My bet is that a round ball is going to be the most accurate. The only way to tell for sure is to measure the rate of twist. Anything 60/1 or greater is going to do best with a RB.

To choose the correct RB size, you need to start with your patching. Mic it loose, i.e., don't tighten the mic down so hard that you can't pull the material out. It should feel draggy but it should come out without a great deal of tugging. If it is something thick like pillow ticking this will be just about perfect when wrapped around a ball. Then subtract this value from the bore dia. This is the size ball that you will need.

As to that shotgun bore, I'll bet dollars to doughnuts that it's a 16 GA. Most of the combination guns were from my experience. For that, you will need 14 GA wads and cards.

I hope this and what others have written helps you to get started. Good luck!

07-20-2006, 02:02 PM
Thanks, Guy's for all the good info...I'm gonna try to get some pics of the rifle to put on here. I have been in my machine shop today making a slug puller, that is going to let me go about half way down the bbl.

My Dad kept a log on this, and all his other guns, and both my brother and I inherited his record keeping habit, and have logs on all of our shooters. After my Dad passed away, the log on this gun never surfaced. I have had it in my Gun safe for about 15 years now, and it's time for me to gather some data, and get it shooting again....I'll keep you posted..

07-20-2006, 05:30 PM
You know, I all most forgot, the value of the patching thinkness needs to be doubled. You take the thinkness times two since at any given pont on the ball you will be in contct with two opposing surfaces.