Cast bullet size

[Outpost75]

Outpost,
I'm not sure I'm understanding everything properly, but not all chambers are the same. I have Rossi '92 lever actions chambered for the straight-case .357. Their "throat" is not like the diagrams posted in this thread. They have something more like a cone. So to size for throat diameter you'd need a .375 boolit or something like that which would not do. Basically it would be a like a big .22 longrifle with boolit and case the same diameter.

In "black powder type" rifle chambers, typically in revolver "Cowboy" calibers such as the .38 Special, .44 Magnum, .45 Colt and .45-70, in which there is no "throat" or "ball seat," before the origin of rifling, load a lead bullet of the largest diameter which provides safe case release clearance, producing a loaded cartridge diameter which measures 0.0015"-0.0020" less than a chamber cast at the case mouth. This permits a loaded cartridge to be chambered easily and extracted without firing, doing so without difficulty. Light marking of an exposed front driving band or exposed bullet ogive which does not impede easy chambering or extraction of unfired rounds does no harm.

In my Marlin Microgroove rifles I load .360" in .38/357, .433" in .44 Magnum, .455" in .45 Colt and .460" in .45-70. Your mileage may vary.

[Steven66]

In "black powder type" rifle chambers, typically in revolver "Cowboy" calibers such as the .38 Special, .44 Magnum, .45 Colt and .45-70, in which there is no "throat" or "ball seat," before the origin of rifling, load a lead bullet of the largest diameter which provides safe case release clearance, producing a loaded cartridge diameter which measures 0.0015"-0.0020" less than a chamber cast at the case mouth. This permits a loaded cartridge to be chambered easily and extracted without firing, doing so without difficulty. Light marking of an exposed front driving band or exposed bullet ogive which does not impede easy chambering or extraction of unfired rounds does no harm.

In my Marlin Microgroove rifles I load .360" in .38/357, .433" in .44 Magnum, .455" in .45 Colt and .460" in .45-70. Your mileage may vary.

Thanks for this. I was worried my Ruger 77/357 chamber was wrong. It measures 0.3615" just ahead of the case mouth. I'm planning to get a NOE mold since they claim a diameter of 0.360" for their 38/357 bullet molds using wheel weights. The 360-154-WFN-AN1 seems like it would work well.

[Outpost75]

Here is useful example, Accurate #31-215B as-cast at .316" diameter in Yugo nny 7.62x54R brass, chambered than extracted from a Tikka M39 rifle. Rounds with the unsized .316" bullet chambered without resistance, and upon extraction shot light, but distinct marking at the throat and also on the forepart where it contacts the origin of rifling.

This demonstrates perfect bullet "fit" and yes, these bullets shoot very well indeed.

Attachment 225946

[a danl]

because if the cast bullet is too small you will get gas cutting and that will completely ruin accuracy . lead is a totally different situation to deal with, hardness,lube, shape, etc all according to velocity. and of course leading of the bbl which no one ever wants.

[gypsyman]

Obturation of a bullet will have something to do with accuracy and leading.

[rickt300]

I have shot a bunch of bullets unsized with no ill effects and very good accuracy.

[PWHeyes]

I shoot a .45 Schofield made in 1876. I have been using cast .454 230-grain bullets from Montana Bullet Works in it and getting excellent results (much better than I get in my Uberti Schofield clone, which has never been satisfactory). I was rather dismayed to find that Montana Bullet Works no longer stocks a 230-grain bullet in the .454 diameter. I understand that using a .452 diameter will cause tumbling and consequent inaccuracy.

I looked online and there are plenty of 230-grain .454 bullets available, mostly from Speer, but these would be commercially "speed"-cast, subject to variations in weight and balance, and I'd rather not use them

I have written to Bruce at MBW to ask for help, but was wondering if anyone here has suggestions. I don't have the facilities to cast my own bullets, so am looking for something to buy.

[gifbohane]

I bought an NOE 359-121-RN-R-3 mold to cast 9mm. 9MM translates to a little over .354. Do you folks think that I have the right mold?

[Rapier]

First thing is slug your barrel, always get ihe exact groove diameter, size to the groove diameter or no more than .001 over. Cast bullets without a hollow base, do not obturate....expand with pressure.

If you have a messed up barrel, big, little, big, well not very much is going to help that, but a rebore or new barrel. Cast shooting for accuracy at any longer distance requires good, clean and smooth, grooves and lands.
You can throw rock and hit a can at 10 feet.

[300leonidas]

If you forget EVERYTHING you ever read about slugging barrels and simply cast chambers from now on, and get bullets to FIT THE THROAT you will be far happier in the long run.

I greatly appreciated your post. There is a lot of good info in there! I made a chamber cast of my old 30/40 Krag. See attached image. Based on everything you've said, I would be well suited to size my cast bullets to .311. Correct?

It seems a lot of people recommend that the front end of the cast bullet "kiss" the lands. I take that to mean it should almost touch. Maybe .001-.002 away from touching? The front part of the boolits I've been making will never touch the lands because the only part that measures .311 is the part inside the case. The entire front half of my boolits measure around .300". Only the portion inside the case measures (or will measure after I size them to .311) large enough to fit snug in the throat.

Is that a problem?

30-40-chamber-cast.jpg

[deltaenterprizes]

Don't you guys mean to size larger than groove diameter?

I was just wondering about that!

[Bill38/55inBC]

I was just wondering about that!

Bore is commonly used term for sizing, which is incorrect but still gets used and parroted

[coltowner]

I am pretty new to casting. Why are my bullets measuring several thousands less than the size of the mold. Specifically, I'm trying to cast some bullets for my 22 Savage HP. The mold is a Lyman 228367 and the bullets come out about .225 to .226. I'm using wt. Docastings shrink as they cool?

[billmc2]

I am pretty new to casting. Why are my bullets measuring several thousands less than the size of the mold. Specifically, I'm trying to cast some bullets for my 22 Savage HP. The mold is a Lyman 228367 and the bullets come out about .225 to .226. I'm using wt. Docastings shrink as they cool?

I'm relatively new to casting as well; only been at it a couple of years now. I don't know very much but no one else has answered you. I'll give it a try but I could be all wrong.

First off, when anything cools it contracts. The lead in the mold needs to do this otherwise you'd never get the bullet out of the mold. I think if you start with a higher temp lead it will shrink faster and further than a lower temp lead.

I don't know this for a fact but I believe the mold maker adjusts for the shrinkage based upon the alloy that is to be used. I've noticed that many of the mold makers state their molds use wheel weight alloy; I'm not exactly sure what mix of metals that is. I've been buying #2 alloy from Roto Metals; it is supposed to be 90 -5-5, lead tin antimony. Because of the alloy I use and the molds not being cut for that alloy, my bullets weigh less that what is stated on the mold.

I powder coat my bullets after casting then size them after the powder coat. Because of that procedure, I've never really measured the diameter coming out of the mold. Prior to powder coat, it would have been ideal to drop out of the mold at the correct size then all you would need to do is lube them. Because of the powder coat, I never bought a lube-sizer. I use the Lee push through sizer.

[Cujo665]

Is casting and sizing to .309 a good fit for a Winchester Model 94 pre-64 in 30-30

Have the Lee #90368 mold in 309 diameter casting 170 grain C309-170-F and 150 grain using the C309-150-F mold

I’ve been loading my own using Starline new brass, Remington 9.5 primers, Hornady interlocks 170g, and IMR 3031 at 27grains. Want to try my hand casting. Have all the equipment recommended from reading through mountains of these threads. Pretty sure 309 will be perfect but thought perhaps somebody’s already done what I’m doing.

[OTShooter]

I am pretty new to casting. Why are my bullets measuring several thousands less than the size of the mold. Specifically, I'm trying to cast some bullets for my 22 Savage HP. The mold is a Lyman 228367 and the bullets come out about .225 to .226. I'm using wt. Docastings shrink as they cool?

Where are you measuring that diameter? What alloy are you casting with? Lyman likes to specify their own alloy, often their #2 alloy (1 part tin to 10 parts lead), and it has specific characteristics like thermal contraction. However, whatever alloy you're using, you have to measure the largest diameter.

Everything I can find on that mold says it should make bullets that are big enough to size to 0.228", so there's something off in how you're casting or how you're measuring.

[whisler]

Lyman #2 is 90% Pb, 5% Tin and 5% Antimony.

[OTShooter]

Lyman #2 is 90% Pb, 5% Tin and 5% Antimony.

I can't recall off hand where I got that 1:10 formula. A simple search brings up the proportions you list - in hit after hit after hit. My bad.

Anyway, on page 297 of Lyman's Cast Bullet Handbook, 4th Ed, they give a formula to make #2 alloy from wheel weights (9lb WW, 1/2lb lead, 1/2lb tin) or from Linotype metal (4lb Linotype, 1/2lb tin, 5 1/2lb lead). This of course assumes wheel weights have a consistent antimony content, but still. In other words, it should be easy to make/recreate/simulate the alloy Lyman expects their bullets to be cast from.

[10x]

Why is it that I reload with a .308 size jacketed bullet and yet the cast boolits are .309 and the sizer die is also .309? Why are cast boolits .001" larger than the bore of the firearm?

The throat of the chamber of the rifle barrel is the best resizer. About 50 years ago i discovered that Marlin MicroGroove® rifles in 30-30 shot far smaller groups with a 0.311" bullet than a 0.309" bullet. When shooting various .303 British rifles i have discovered that bullets 0.002" or larger than the measured bore diameter shoot smaller groups.
Currently I size alox lubed and powder coated bullets to the largest diameter that will allow easy chambering in the gun. Sometimes this is 0.003" or larger than bore diameter.
My 9.3x57 with a copper bullet diameter of 0.366" will shoot much smaller groups with a cast bullet sized to 0.368" - and 0.368" requires that i thin the necks of my 9.3x57 brass to get these bullets to chamber easily.