Slugging a rifle barrel

[Highland Lofts]

A local guy bought an old 8mm mauser and wants to reload for it and was told it has a bore size of one size and then a bore size of another size.
So to be sure it will need to be slugged.

What's the easiest way to slug a barrel?

I watched a YouTube video and they took a over sized blackpowder round ball and forced it through the barrel with pieces of a wood dowel them measured it.
They measurd the grooves and the outside diameter and said to go I thousands of an inch over the outside diameter.

His rifle is suppose to be a 8mmJ.
.317 diameter.

So if it is the smaller .317 bore would the expander need to be different from the standard 8mm expander ball?

 

[mdi]

Use a brass rod. Wood may splinter and get jammed really tight in the bore. If you can't find a brass rod, wrap a steel rod with electrician's tape to protect the bore. When starting the slug do not use a steel hammer, use a plastic mallet (even a brass hammer may damage the barrel crown). Some commercial casters have slugging kits with appropriate sized slug. I have measured some egg sinkers and some bullet sinkers to use a slugs and they worked quite well. Lube the slug and the barrel, I use white grease on the slug and drizzle oil down the barrel. I have slugged probably every firearm I own (even a couple 22 lr guns). Good info to have...

 

[Blue68f100]

Make sure you use pure lead, NO ZINC. Oil the barrel and lead before you start driving it through the barrel. For hand gun I use shot/fired brass as a lead mold. This normally gives you a taper to get started easily. Fishing singers or buck shot near the same size works. Closer to the bore size the better. Wood is a bad idea since it can splinter and wedge the slug in place making a major chore to remove.

 

[NMexJim]

Casting the chamber might be a good idea as well. Brownell's sells Cerosafe 1/2 lb for $16. It's pretty easy to use and will give you chamber, throat condition, jump, and all that good stuff. Might give you a quick idea if the work is worth the effort. Mausers can be in pretty rough condition.

I still have a couple of bins of parts left over from messing with them years ago. I did get a couple of fairly good shooters though. Note that I said "fairly".

Another suggestion would be to check all the serial numbers to see if they match. If it's mix and match, then that's not a really good sign.

Anyway, good luck.

 

[AJC1]

Two good options pure lead or the chamber casting material. For God's sake never use wood. First choice would be brass second an aluminum rod. There are two distinct 8mm sizes and a I believe the larger size won and is the standard. Either way it's easy unless you use a wood dowel and it brakes, then you have a nightmare.

 

[film495]

never having done it before, I got my hands on round ball lead rounds, and jammed one through, well - I did it a few times, a barrel and measured it. I don't recall if I used a dowel or brass rod, not sure it matters really, after the initial shaping of the lead it isn't super hard to push it through the rest of the way. I don't reload that cartrdige any more, just not worth it to me, but - I recall based on the results I did end up sizing bullets smaller, and I got my hands on some dies that were a bit different from RCBS when I explained it to them, I think they just send me a different expander or something. slugging the bore is a good skill, expecially with older stuff or stuff that has questions about it. My guess is I really had no need to go through the effort I did, but - I'm risk averse and once the question came up for me, I had to have it answered and it is all a learning experience IMHO, just do it safely.

 

[DM~]

I NEVER use lead, here's another vote for Cerosafe!

DM

 

[BJung]

I use lead. One method I read of is to find a drill bit close to and just larger than your bore. Drill a shallow hole in a 2x4 and melt enough of a commercial fishing sinker to fill the hole. Dig out the lead with a knife, grease it and drive it through your bore. Using the same instructions above works. Be sure to find a micrometer to measure the slug. I don't think an outside caliper is good enough. I've read that you can do about the same thing using a lead slug and driving it into the chamber, far enough to get an imprint of the front chamber dimensions. I never did this nor have I used cerrosafe. However, I was able to determine my maximum case overall length. Note the attached photo. Unfortunately Sinclair does not make an 8mm guage. Maybe there are other options. My suggestion is cut the neck off a bad or useless and sized 8mm case of yours and tap the neck over the base of an 8mm bullet. Then, Trim the neck of an unsized bad case like you see in my photo. Teflon the bullet and insert into the case, then insert the cartridge into your chamber. Eject and measure your chamber OAL.

 

[Barbaroja]

Slugging a bore is simple and easy don’t let it intimidate. A black powder round ball works perfectly/pure lead egg sinker from the tackle box works too. Oil the bore, use a nylon type hammer to get the ball started into the bore. I’ve used hardwood dowels every time if done it. I’ve never had one break like people warn about. Use caution of course because it can happen, but it’s doable if you take your time.

 

[GeoDudeFlorida]

I’ve used Cerosafe and lead round ball and got good results from both. Cerosafe is easier - as long as you remember to measure before it’s room temperature because it shrinks a bit when it cools. Lead balls take more effort but they don’t shrink and once you have a good impression, you have it forever. But you can’t cast the chamber and neck with lead like you can with Cerosafe. As for dowels vs rods, I’ve always just used an old cleaning rod the handle broke off of and a brass jig. Your calipers are good enough to measure the lands and grooves at the muzzle so you know how close to get the lead ball - or sinker - before you start. Don’t use a .35” sinker to measure a ~.323” bore. Too much work.

 

[SingleActionAndrew]

Starting at the crown?

 

[Highland Lofts]

I'll probably use a piece of lead when he brings the rifle over.
I'll find a piece that is close to the barrel diameter.

 

[gwpercle]

I used a Lead Fishing Sinker ... called a Bank Sinker ... round shaped larger at the bottom and smaller at the top ... grease both bore and sinker (thats important) and start the small pointed end of the sinker in the muzzel with the larger fat end up ... I bought an assortment of weights to make sure I got an over sized sinker ... one too small wont work ... gently use a wood / plastic or rubber mallet to start the sinker into the barrel ... when flush .. I used an old cleaning rod to tap the slug through the barrel and out the chamber end .
Don't forget ... grease slig and barrel and wood rods can break and stick ...
Go slow and gentle .
Gary

 

[hdwhit]

If you use Cerrosafe (and that's what I use), the dimensions do change in the hours after the casting, so be prepared to make your measurements shortly after you do the casting.