"slugging the bore" question

[ProfessorX]

I'm still playing with my 7.65 Argentine Mauser (also called Belgian Mauser) and researching how to reload ammo for it. Because of it's age, I want to slug the bore instead of "guess" on bullet diameter. My basic question is how to best slug the bore:

Method #1: Someone I know has suggested the following method, using low-melting point lead. The first step is to block the bore using something tight fitting such as a disposable ear plug. This ear plug is inserted into the muzzle and then pushed down the barrel about 5 inches. Next, molten lead is then poured down the barrel and forms a "slug" on top of the inserted ear plug. Then this slug is then pushed thru the barrel using wooden dowels until it comes out the other end (chamber). - Will this method work? (I have never heard of this method before.)

I have further been advised to get BOTH measurements from the slug, the lands AND the grooves, and that the final bullet diameter should fall BETWEEN those two measurements. Any advice? Thanks!

 

[blarby]

Sounds like a lot of work when a lead round ball, or pure lead fishing sinker, would work.

You can just start the roundball or sinker of the appropriate size over the oiled muzzle, tap it flat, then tap it through with a wooden dowel.

 

[rcmodel]

and that the final bullet diameter should fall BETWEEN those two measurements.

No, the final bullet diameter should be the bore groove diameter.
(measure the lands on the slug)


And I would not plug the barrel and pour molten lead in it.
You might not get it out.

+ molten lead will melt a foam earplug instantly and the lead will run into the action.

Use a lead buckshot, fishing sinker, etc.
Drive it through, then measure it.

rc

 

[ThePenguinKnight]

What RC said.

Also, while I've not tried it with wooden dowels, I have read a great many times of people being advised against using wooden dowels for slugging as the dowels can break and wedge in the bore, becoming nigh but impossible to remove.

Brass rods and stiff coated cleaning rods have worked well for me.

 

[Blue68f100]

When I'm slugging a pistol caliber I normally will use an unsized brass as a mold. Melt 100% pure lead into the brass base. The base of a casing is tapered which makes it easy to start and drive through. It helps to preheat the brass too. Use an kinetic bullet puller to get the lead slug out of the brass. Run a oil patch down the barrel and oil the slug. If the barrel can be removed (auto) drive the slug from the chamber end. Then measure with calipers or micrometer. If it's a odd number of lands it will be hard to get an accurate reading. Use brass or AL rod. Wood can splinter and wedge the plug in the barrel.

 

[rondog]

When I'm slugging a pistol caliber I normally will use an unsized brass as a mold. Melt 100% pure lead into the brass base. The base of a casing is tapered which makes it easy to start and drive through. It helps to preheat the brass too. Use an kinetic bullet puller to get the lead slug out of the brass. Run a oil patch down the barrel and oil the slug. If the barrel can be removed (auto) drive the slug from the chamber end. Then measure with calipers or micrometer. If it's a odd number of lands it will be hard to get an accurate reading. Use brass or AL rod. Wood can splinter and wedge the plug in the barrel.

Wow, what a great idea! Possible to use a pistol case to make slugs for .30 rifle barrels? I have two Mosins and five Enfields I need to slug.

And with old milsurp rifles, should one first make every effort to get all copper, lead & carbon deposits out first? I'd assume so, but I've never slugged one.

 

[LAGS]

I use either a Buck shot ball that is larger than the bore, or a cast lead bullet of the correct caliber.
A Brass rod close to the size of the bore works best, but you can use aluminum rods also that are close to the bore size.
I, for many years used a wooden dowel to drive the slug thru the bore, and have never broken them off in the bore.
But I have heard many stories of others doing just that, and breaking or shattering the wood dowel.

Also.
To slug a Barrel Properly, you need to slug it at many different points.
Like Drive the slug in to the muzzle, about an inch, and then drive it out from the chamber end.
That will tell you how the barrel is in the last inch of the bore.
Also, drive a slug into the barrel from the chamber end about 1" into the throat just into the rifling past the freebore, then drive it back out the chamber from the muzzle end.
That will give you an idea of the condition of the start of the barrels Rifling.
And if you feel a restriction or a jump in the slug like it is a loose spot, note the distance down the barrel and reslug to that point from either end of the barrel.
That will tell you if you have a bad spot in your rifling like rust or corrison if there is a resistancee when driving the slug thru.
And if you feel like the slug Skips, or has No Resistance at a spot in the barrel, you may have an Internal Buldge, or a Slick spot in your rifling.

 

[judgedelta]

I believe that 000 buckshot is .358. There are 8 or 9 in a 3" 12 ga. load. Ought to be enough for what you need. 00 may be closer to your bore size though...

 

[LAGS]

The size of your Slug if Lead , Just has to be larger than the bore.
If you are using a Lead ball that is larger than the bore the Excess is cut off as you pound it into the barrel.
00 Buck balls are .33" and 000 buck is .36"
Either will work on a .312 bore like the Argintine.
But the 000 buck being larger to start with , will give you More Surface area contacting the bore, and will be easier to read and measure.

 

[deadeye dick]

What I do is ( for instance) .45acp; I take a lead slug put it on a anvil and smack it with a hammer until it bulges a bit (that expands it)than pound it through the bore. Works every time.

 

[amlevin]

I wouldn't just stop with slugging the bore (at both ends like LAGS said) but I would also "cast" the chamber end of the barrel.

Get some Cerrosafe. Following the instructions plug the bore ahead of the throat area with a patch or two and pour the melted Cerrosafe into the chamber. Be sure to stop before you "overflow" into the locking lug area or you'll have difficulties removing the "cast".

Cerrosafe will give you exact measurements of the chamber, shoulder, neck, free-bore, and throat condition when measured at the suggested time after pouring. Of course it's imperative to clean the chamber/throat carefully before casting.

Cerrosafe (also known as "Woods Metal") melts between 158 to 190 F. so you can just about melt it in a double boiler on the stove.

I like to use a small Lyman pouring ladle as it gives me better control in pouring than from a larger melting pot.

 

[clearcut]

Hey X pm me your address and I'll send you some slugs to check your argi with.
CC

 

[ProfessorX]

Clearcut.... Sent you a PM. THANK YOU! And if I can help you, let me know.....and if i can't, I'll play it forward to someone else.

 

[clearcut]

X slugs are sent

CC