'Slug' Size Question

[Fugowii]

What size (diameter) 'slug' would I need to slug the following barrels? Would it
be a general .005" (est) over the caliber dimension? Or some other rule of thumb?

.45
.44
.357
.38
.32
.30

TIA,
F

[SP101GUY]

I used a boolit cast of pure lead for slugging all my bores. Sizing first makes it easier to run through. If you don't cast for your calibers, there might be someone on the board that could send you a boolit to slug with. They all seem to be a generous lot.

AJ

[243winxb]

Cerrosafe might be a better idea if you have that many firearms to measure. http://www.midwayusa.com/viewproduct/?productnumber=462291&utm_source=froogle&utm_medium=free&utm_campaign=685
Cerrosafe is the best known material from which to make a casting of the chamber and throat of a firearm - to determine caliber or check the dimensions. It melts at a temperature just above M&M's, so all you need is a propane torch and a bullet casting ladle. It can also be used to make a cast of a dovetail slot or any other hard to measure area. Also, it is great for removing the front half of a case from the chamber, in the event of case head separation; and lots of folks cast a small portion of the barrel to determine bore diameter. For best results, measure the casting one hour after casting.

Basic Instructions:
# Plug the bore immediately ahead of the throat of the chamber using a small cleaning patch.
# Pour the alloy directly into the chamber until full and allow it to cool, it will turn a shiny silver color. As soon as it has cooled enough that it is no longer a liquid (and doesn't present a burn hazard), remove it from the chamber. Take care not to overfill the chamber as the alloy will then run into the locking lug area, making removal extremely difficult.
# During the first 30 minutes of cooling cerrosafe shrinks. At the end of one hour it should be "exactly" chamber size.

Notes
# Melts between 158 and 190 degrees Fahrenheit
# Should be melted in a clean iron ladle without direct flame on the product.
# The chamber being cast should be cleaned thoroughly and a thin coat of oil or graphite applied.
# Reusable

Contraction - expansion factor versus time, measured in inches per square inch:
# 2 minutes -.0004"
# 6 minutes -.0007"
# 30 minutes -.0009"
# 1 hour +-.0000"
# 2 hours +.0016"
# 5 hours +.0018"
# 7 hours +.0019"
# 10 hours +.0019"
# 24 hours +.0022"
# 96 hours +.0025"
# 200 hours +.0025"
# 500 hours +.0025"

[462]

Fugowii,

Keep in mind that, when it comes to revolvers, knowing the size of the cylinder throats is more important than knowing the bore diameter.

[mooman76]

Usually you want it a few thousandths over bore size or estimated bore size. It get a little trickier with 30 caliber because they have a wide range of what they could be. For none American 30 calibers usually run slightly bigger than american which usually run from .308 to .310 but sometimes smaller. The non American guns like AKs can run as large as .316. That's why I like to use RBs to slug with. It allot easier to run a RB slug down a barrel that is .005 larger or even more that it is to run a bullet shapped slug down the barrel. If your slug comes out well defined with the rifling showing good, it should be a good slug form.

[plumber]

I slugged my bores with buckshot last weekend and just measured them with my newly aquired micrometer. I was wondering, will the slug grow? Do I need to re-slug to get it right? I ran the buckshot from muzzle till they dropped out the chamber.

[Fugowii]

Fugowii,

Keep in mind that, when it comes to revolvers, knowing the size of the cylinder throats is more important than knowing the bore diameter.

Why would that be? I would think that bore size is where the action is and the
need to 'seal' the bore with the slightly oversize boolit. Is there a different rule
of thumb for pistols (1911's)?

[Fugowii]

I slugged my bores with buckshot last weekend and just measured them with my newly aquired micrometer. I was wondering, will the slug grow? Do I need to re-slug to get it right? I ran the buckshot from muzzle till they dropped out the chamber.

What size was the buckshot and what bores did you slug?

[Catshooter]

The lead you push through the bore will not change in diameter after you have it in hand.

Double ought buck works well for most .30 cal bores.

You want a clean bore. Oil the slug. I have used a .455 slug to measure a .30 caliber. How? Oil the slug, then drive it down the bore. The excess lead will shave off at the muzzle.

With revolvers, throat diameters are important, just as the bore is important. For example, if your boolit starts out at .452 as it leaves the brass, then hits a .450 throat, it is now .450. Then when it hits the .453 bore, well you see the trouble?

Conversley, if the .452 boolit rattles through a .458 throat, then hits a .453 bore, well that ain't good either. Ideally the boolit's path is smaller and smaller until it exits.

That help?


Cat

[243winxb]

Veral Smith of Lead Bullets Technology sells kits to slug your barrels and throats. Look here for info. 00 buck shot is .33" if my memory is working. Not going to go look. http://www.lbtmoulds.com/

[plumber]

I used 00 buckshot, to slug a M1 Garand , Type 99 Arisaka, SKs, and an AK-47. All 30 cal bores. I asked about the slugs growing because they measure .002" larger with my micrometer than the measurements I took last weekend with my calipers.

[mooman76]

I used 00 buckshot, to slug a M1 Garand , Type 99 Arisaka, SKs, and an AK-47. All 30 cal bores. I asked about the slugs growing because they measure .002" larger with my micrometer than the measurements I took last weekend with my calipers.

That is interesting and I never gave it a thought before. I slugged allot of my guns a year ago and saved the slugs. I will have to measure them and see.

[plumber]

Is buckshot pure lead?

[462]

plumber,

After being cast, a boolit's size will change as it cools and ages. Unless your slug was recently cast, the difference was due to your instruments or technique, not the slug.

Fugowii,

Buy a copy of Lyman's "Cast Bullet Handbook" and read it at least once, however, the more the better. It is the cast boolit go-to reference. Read the stickies and spend some quality time here, too: http://castboolits.gunloads.com/archive/index.php/f-8.html

[plumber]

Nope, I bought a box of 12 ga 00 and cut one open. So I guess my technique with the calipers was off. I went from .312 to .314 and .312 to .313 so the rate of "growth" wasn't consistant on these slugs, so I'll chalk it up to tool ( operator ) error. I am going to re slug to be safe.

I second the recomendation of Lyman's cast bullet handbook, great reading.

[Fugowii]

The lead you push through the bore will not change in diameter after you have it in hand.

Double ought buck works well for most .30 cal bores.

You want a clean bore. Oil the slug. I have used a .455 slug to measure a .30 caliber. How? Oil the slug, then drive it down the bore. The excess lead will shave off at the muzzle.

Thanks.


With revolvers, throat diameters are important, just as the bore is important. For example, if your boolit starts out at .452 as it leaves the brass, then hits a .450 throat, it is now .450. Then when it hits the .453 bore, well you see the trouble?

Conversley, if the .452 boolit rattles through a .458 throat, then hits a .453 bore, well that ain't good either. Ideally the boolit's path is smaller and smaller until it exits.

In either case above the situation has to be dealt with. I am assuming that
in the case of a larger cylinder throat vs the smaller bore than you would size
your bollit to the bore. What the heck do you do with a smaller cylinder throat
vs a larger bore? Size to the throat and let the boolit rattle down the bore or
buy a new cylinder or ream the one you have?

Is the ideal situation a match of cylinder throat and bore to the same exact dimensions?


That help?

Absolutely, every bit helps as it makes me a bit smarter than I was before but I
wish I could get smarter in bigger chunks. :mrgreen:



Cat

[Fugowii]

Fugowii,

Buy a copy of Lyman's "Cast Bullet Handbook" and read it at least once, however, the more the better. It is the cast boolit go-to reference. Read the stickies and spend some quality time here, too: http://castboolits.gunloads.com/archive/index.php/f-8.html

Does my question assume I don't own the book, or read the stickies, or the
archives, or was that just general advice? My question was related to how much
oversize regarding the bore should I have the slug as trying to stuff a .50 dia ball
down a .313 bore doesn't seem like it makes it easier to slug a barrel. I haven't
seen that in any of the above except to say that it should be larger. So then I
ask how much larger so hopefully I can avoid trying to hammer an ingot down my
favorite revolver barrel.

To that end, a poster contributed that the cylinder throat is actually more/as
important than the bore dia so now I have to further slug the cylinder as well to
insure I am not going to size my boolit incorrectly. If you know of a particular
sticky, article, or link that would answer my question(s), and/or save me from
spending hours looking through the archives I would appreciate it if you would
let me know it's whereabouts. If you don't, that's all right too. I'll just muddle on.

[462]

Fugowii,

Offered honestly as general advise.

In the case of larger cylinder throats versus smaller bore, you want to size to the throats.

In the opposite situation, the cylinder throats would need to be reamed to over bore size.

Assuming that the throats are larger than the bore, you want the boolit to be at least .001" larger than the largest hole it will be travelling through.

A bit of googling turned up a very useful site and article, from it: http://www.lasc.us/CastBulletNotes.htm

http://www.lasc.us/TaylorLeadingDefined.htm

[Fugowii]

Fugowii,

Offered honestly as general advise.

In the case of larger cylinder throats versus smaller bore, you want to size to the throats.

In the opposite situation, the cylinder throats would need to be reamed to over bore size.

Assuming that the throats are larger than the bore, you want the boolit to be at least .001" larger than the largest hole it will be travelling through.

A bit of googling turned up a very useful site and article, from it: http://www.lasc.us/CastBulletNotes.htm

http://www.lasc.us/TaylorLeadingDefined.htm

Many thanks. You know I keep overlooking (CRS) that link (lasc) and it is a great site.

[462]

Fugowii,

You are welcome.

[Bent Ramrod]

I've never heard anyone espouse a specific diameter oversize for slugging a given caliber. You could cover your caliber list with a few pure lead muzzleloader roundballs in .451", .375" and .312" diameters. If they are a little small, tap them with a hammer on a steel plate and flatten them slightly. This will increase the diameter.

The round balls (flattened or not) are then tapped into the muzzle of the barrel. I use a piece of aluminum or brass rod to get them started in. Just make sure a small ring or donut of lead is left at the muzzle when the rest goes into the bore and you will get a true reading of the lands and grooves.