What size for 30-30 and 30-40

[JTknives]

I'm casting up some Ed Harris 30 cals from one of the molds I made a while back. I'm in need of advice on what diameter saeco lubrisizer die to get for my 30-30 marlin lever (old) and 30-40 krag. Reading shows that the 30-40 likes fat boolits. So my thought was go as fat as the 30-30 marlin would take which I think is like .311
what do you think, thanks guys.

[MtGun44]

Groove diam plus .002 or .003 usually works well.
Slug the barrels or just try .310 or .311 and see how they
work.

[Outpost75]

Cast the Krag chamber. The cylindrical freebore is most likely. 312-.314 and yoy shpuld size bullets to fit that and not barrel groove diameter.

[Wolfer]

My Krag made in 1898 and my 336 made in 1966 both slug at .308. My mold drops at .309 and I size to that. Their both very accurate.

Until you slug them both its just a guess.

[Char-Gar]

I truly wish somebody would drive a stake through the heart of the old mantra "slug the bore". The size of the barrel groove diameter is all but irrelevant. As Outpost 75 said, the throat is the number you need.

Most 30-30 rifles like .311 bullets. The Krag rifles likes .312 to .314 bullets with .313 being a good mean average. When will this slug the bore stuff die?

In case somebody has not said so lately, the important thing is to start the bullet straight into the barrel and that is the reason why you want a bullet that fits the throat. There is no way you can have a rifle barrel with a throat smaller than the groove diameter. A bullet that fits the throat without being larger and shaving lead will have good chance of being accurate. You don't want a bullet rattling around in the throat before it hits the rifling. This is a lesson we have learned years ago, but it seems to have fallen through the cracks for reasons I know not. Again, don't waste your time sluging barrels when the throat is the important dimension.

[btroj]

It will die around the same time as the harder is better mantra?

Sometimes it pays to play with things and see what size the rifle wants even if it isnt the "right" size.

[Char-Gar]

It will die around the same time as the harder is better mantra?

Sometimes it pays to play with things and see what size the rifle wants even if it isnt the "right" size.

Rifling style (number, width of lands and depths of grooves) will have an effect on the design/style of the bullet that will give best accuracy, but that has nothing to do with the diameter of the bullets. Folks often shoot bullets not designed for the rifling and blame the poor results on the wrong diameter. Conversely people often get decent result with a good bullet even though it is the wrong size.

Best accuracy will be combination of bullet style/shape that is a good fit to the throat. This stuff isn't witchcraft or chance, it is science. Why waste time, lead, powder and primers doing it any way but the right way? Why introduce trial and error and chance to an otherwise simple task?

[JeffinNZ]

Shoot the fattest bullet that will chamber. My Husky .30-30 will chamber a .312 bullet and it SHOOTS.

[JTknives]

How do I cast my chamber, can I use just lead? I don't have any chamber cast material

[JeffinNZ]

How do I cast my chamber, can I use just lead? I don't have any chamber cast material

Sulphur is good. Available at garden/hardware stores. Melt is carefully and pour into the chamber where the barrel is plugged with a patch about an inch past the leade. Don't forget a very light coating of oil.

[newrib]

A quick way to check for what diameter to size a cast bullet to is : Shoot a round (at a proper back stop) then measure the inside diameter of the neck of the fired case and size to .0005-.001 under that diameter. Pin gauges work best but a caliper will work. You want a sized bullet to just slip into the neck of the fired case. Using a full powered round is best as is shooting a round with the same cases you will be loading. This is what works for me.

[Outpost75]

How do I cast my chamber, can I use just lead? I don't have any chamber cast material


Better for measurement purposes and easier expedient is to upset a throat slug, or as some people call it a "pound cast."

Start with a sized case with DEAD primer in the pocket.

Heat up your lead pot, then fill the sized case with DEAD primer pluggng the flash hole, overflowing the case.

After the lead cools, clean any spilled lead off the case exterior, then file the exposed lead flush with the case mouth.

Take a SOFT piece of PURE lead buckshot or a short chunk of pure lead wire and drop it into the EMPTY chamber, letting it fall into the throat of its own weight. (With very long throats you can use a longer piece of wire or maybe a SOFT bullet).

Insert the lead-filled dummy case and gently tap it into the chamber with a piece of brass rod until you can close the breech. You are using the lead filled dummy case to force the lead slug into the ORIGIN of rifling. It need go no farther! What you want to measure is the diameter of the UNRIFLED portion of the chamber forward of the case neck BEFORE the rifling starts!

Extract the dummy and GENTLY tap the lead slug out and measure it.

THAT is the diameter you want to size your bullets to!

Cerrosafe, etc. is more trouble and you then need to compensate for shrinkage, etc. The upset pure, dead-lead slug is exact and straight forward!

[btroj]

Never heard of it being done quite that way but I like it. Far easier than most throat upset slugging methods I have read.

[wmitty]

Outpost75

An excellent description of an easy way to determine throat diameter!

[JTknives]

Ok I did just that and I'm getting some weird numbers. Seams like the throat is not round.
the rifling right in that area is .302 and .309 and the neck area is exactly .338. But now onto the throat, rig after the neck it goes from .315-.320 then down about .1 from that it's .312-.315. My lead slug was not long enough to get reliable numbers past that but .200 down seams to be around .310. So I don't know what to think as the throat does not seam to be round. Do I take the neck size of .338 and subtract the brass thickness of .012 per side and subtract it from .338.
.338-.012-.012=.314. But that would give no slop and might be hard to chamber. If I measure the inside of fired brass I get .314-315. So do I try and shoot a .314 or not? Thanks guys

[edctexas]

The pound cast works, and so does cerrosafe. BUT!!! Cerrosafe is tricky!! IF you get it to close to where the bolt locks up, you may never get it out of the chamber!! Voice of experience talking here. The method described for pound cast works great.

The measurements of your cast done by any method are tricky for a first timer to measure and understand. There is a thread with pictures of the chamber cutaway for a 30-06 in a recent thread. This might help you understand what you are looking for. After looking at the photos, I remeasured my cast and changed what dimension I was going to cast and size for (308W 700 Remmy). Anyone casting with cerrosafe should talk to someone that has done it before. PM me if you need tips.

Ed C

[JTknives]

Nobody have any advice on the numbers I found above?

[Hamish]

JT, it sounds like your slug was not big/long enough that when it was forced up into the leade to actually completely fill the free bore cavity, so it would make it appear that the area is egg shaped.

[JTknives]

I hammered the lead into the throat using a steel rod from the muzzle. It looks like a good fill out to me. I did it 4 times and the numbers all came out the same.

[Harry O]

What shoots best in my Krag is a Lee 303-B cast bullet. This is supposed to be for the .303 British. They have a similar one for the 30-06. It is actually a mix of dimensions for the two guns.

The base casts at 0.314", but the bore riding portion is only 0.300" (it should be about 0.303" for the British). However, that works for the Krag. I size the base at 0.312" and it is the most accurate cast bullet I have for that gun.

[Char-Gar]

I hammered the lead into the throat using a steel rod from the muzzle. It looks like a good fill out to me. I did it 4 times and the numbers all came out the same.

Reading that just give me the willies. I would never hammer on a steel rod in a rifle barrel. Neither would I trust a measurement obtained by doing so.

[JTknives]

Reading that just give me the willies. I would never hammer on a steel rod in a rifle barrel. Neither would I trust a measurement obtained by doing so.

Thats what I was told to do. And reading on line seams to be a common way to measure the throat/chamber

[Char-Gar]

Thats what I was told to do. And reading on line seams to be a common way to measure the throat/chamber

If you want to expand a dead soft lead slug in the throat, you do it from the breech end with a brass rod with taps and not hammering. Hammering on a steel rod that is in the barrel full length is a good way to damage the barrel.

When we clean a barrel with a steel cleaning rod, we use a rod guide at the breech or muzzle, depending on which end we are cleaning from to prevent the rod from flexing and/or rubbing on the inside of the barrel. Steel on steel is not a good plan for protecting and preserving the quality of your barrel. This is the reason some folks use aluminium or coated cleaning rods. A steel rod works fine for cleaning, but it must be clean and centered in a rod guide.

I don't know who told you to hammer on a steel rod in the barrel, but you either misunderstood or they were giving bad advice.

My best counsel to you is to forget trying to pound lead into the chamber and throat. Size your 30-30 bullets .311 and you 30-40 bullets .312 or .313 and go shooting. Those number will give you good results if everything else is right as well.