cast size for 45-70

[Gerry2]

For my .30 cal rifles, I generally use .309 to .311 sized cast bullets. in my 45-70 I've been using 348 gr .458 sized 350 gr bullets that I buy from a local gun shop. I want to buy my own mold but find they are generally under bore size. Jacketed bullets for 45-70 are .458. Why are most molds .457? All Lyman and most Lee molds are .457. Lee do have 2 molds that are .459. Why? (I shoot a H&R 45-70Buffalo Classic.)

[Gerry2]

I would also like to know the purpose of hollow base molds.

[Buckshot]

.............You must be refering to the mould catalog numbers. It really doesn't have a whole lot of bearing on what the mould actually drops. However, I HAVE found the Lee 340 and 405gr solids to cast a bit on the small side. However that isn't an issue with Lyman, RCBS, and Saeco moulds. I have 45 cal rifle moulds from the 3 mentioned makers and with WW alloy they'll all drop boolits .459" or larger.

.............Buckshot

[bushka]

All I can think of is 457 being the as cast diameter if one uses pure lead.
Using an alloy would make the as cast diameter larger,like 458/459.
Most would use an alloy,even scrap having some tin/antimony in there would
fill the mold "fuller" .
Modern bores ,like on a Browning 1886,would be tighter than an original 1886.
Hence the various diameters you see can be worked to your bore.

Hollow base bullets are for obturation,as in the Minie` ball system,later adapted into early civil war breechloading rifles,and later more= percussion revolver cartridge conversions,using the existing barrel bore without relining,or using heeled bullets like on a 22lr or 38LC.

a better explanation will be forthcoming[smilie=1:

[cohutt]

i always thought .457 was for 45lc (?) \\
(disclaimer: my experience casting has been mostly pistol rounds 44, 45acp and 9mm)

i just bought the following:
RCBS 2-Cavity Bullet Mold 45-325-FN-U 45 Caliber (458 Diameter) 325 Grain Flat Nose Universal

same rifle as you, 1871bc. also using an ohaus 405g, which seems to drop them a little fatter, and both are hitting the sides of the 458 sizing die to say the least. I'm casting using ww with a little lino and a very little bit tin added. 4:1 i think.

early results are pretty good- no leading, velocity is higher than manuals led me to expect, maybe due to the 32" barrel

i salute you for asking, i didn't....

[cohutt]

and fill the stock with lead shot if you haven't yet...... Your shoulder will thank you.

[floodgate]

Gerry2:

Other possible reasons for the more modern use of the hollow base arose in connection with a couple of the Keith designs - 358431 and 429422. As to the first, the "customers" wanted to have bullets of "standard" weight (158 grs in .38/357 vs. the 175 or so of the 359429), but retain the full-length Keith profile. But the 429422 HB was only about 10 grs. lighter than the solid-base 429421 (235 vs. 245 grs.) and both were in the same range as the standard .44 RN's; the only thing I can come up with is a note on p. 153 (bottom right) of the 1958 "Handbook of Cast Bullets", which reads: "429422 - Same as 429421 except for hollow base. Gives flatter trajectory." (Not by much!) A stability issue, maybe??

floodgate

[leftiye]

Hollow bases wouldn't work very well with higher pressure loads (so high velocity would be impeded) as they will blow the skirts out and mess up both accuracy, and ballistic coefficient. Mainly used in midrange loads for pistols, and slower loads in rifles.

[44man]

It is hit or miss when buying a mold as to what size it will cast. I had a Lyman that would be hard pressed to reach .458 with any alloy. I have to make my own molds for my Browning BPCR, the bore is .4594". I have tried all diameters and it is starting to shoot better with .464" boolits. I am doing this to fit the case mouth to the chamber as per 45 2.1's suggestion. He designed a great boolit for me. I have yet to get to the range and try it at 500 meters.
The only off the shelf molds I know of that offer larger choices are Rapine molds. He makes a great mold and they are not expensive.
For most guns, .458 is too small, I would not size them until the bore is measured. .459 to .460, on the average will shoot better. Not the same as jacketed where .458 usually works great.
It just depends on your gun and what it likes. Don't be afraid to go larger. Don't think that the boolit has to be run through a size die.
But good luck with store bought molds and the hope of getting a large one. Only happens with a new cherry, after they re-sharpen them, molds get smaller.

[Gerry2]

I didn't think it possible for the bullet to be larger than the mold it was cast in. Does it expand as it cools after being dropped from the mold?

[felix]

Only if it contains antimony. How much expansion depends on the proportion of antimony in the mix in addition to the exact amount. ... felix

[Gerry2]

If I use a .457 Lee mold with straight wheel weights, will I get .458 or larger bullets?

[montana_charlie]

I didn't think it possible for the bullet to be larger than the mold it was cast in. Does it expand as it cools after being dropped from the mold?
Speaking of the Lyman .45 caliber mould designations...

The companies that make mass produced moulds each have an alloy which that company considers to be it's 'standard' for adjusting the diameter of their moulds.

Custom makers cut a mould to throw a certain diameter with the alloy the customer wants to use.

Lyman's 'standard' is (the fairly hard) Lyman #2 Alloy, so that tells you where they are starting out.
Lyman also assumes that the customer will run a cast bullet through a sizing die.
Lyman #2 alloy is hard enough to have some 'springback' so their sizing dies are a bit undersize. If you run a bullet through their #458 die, it passes through a hole closer to .457"...but because of the springback, it swells back up tp .458" for you.

As for the '457' mould designation (as I understand it), Lyman assumes .457" is the smallest a customer will want to use in a .45 caliber rifle.
So, their moulds are cut to throw a bullet of #2 alloy, which will not be seriously deformed if run through their #457 sizing die (with a hole closer to .456", but enough springback to return to .457").

Obviously, this means the moulds throw 'as cast' bullets that are larger than .457". How much larger depends on which of several cherries was used to cut a particular pair of blocks.

Frequently, there is a two-letter code after the number designation. Those letters (when present) often identify the cherry used to cut that mould. If somebody has a 457132 CH (for example) and it throws .458' bullets you may not want it for a (say) Pedersoli rifle with a .460" throat.
If somebody else has a 457132 CK which throws .460" (as-cast) bullets, then you know which cherry you want them to have used when cutting a mould for you.

Finding out which letters are right for you...and finding a retailer who has a mould in stock with the right letters on it...well, that's the quest.
CM

[BruceB]

Here are some measurements taken from bullets on my bench. All were cast HOT (870 degrees) from straight wheelweight alloy. All were measured at 90 degrees from the parting line.

My Shiloh .45-2.1 has a (slugged) groove diameter of .4575", and I usually use a .459" sizer. Some of the following measurements were taken on bullets already sized in the .459" die, and if the final diameters in fact are .459, then they obviously were large enough to fill that die in their as-cast state. I don't have naked as-cast examples of all the bullets, so I'm reporting some dimensions after sizing.

Lyman 457406, 500 RN, sized in .459 die: .456"....obviously badly undersize as-cast.

Lyman 457122, 335 hollowpoint, sized .459: .459"

Lyman 457483, 380 RN, sized .459: .459"

SAECO 420 Spire point, sized .459: .459"

Hoch 459430, 425-grain, nose-poured flat nose, sized .459: .458"

LEE 405 hollow-base, unsized: .460"

Lyman 462560, 550-grain flat-nose, unsized: .463"

Perhaps this info may be of some assistance.

[duke76]

If I use a .457 Lee mold with straight wheel weights, will I get .458 or larger bullets?

Sunday I cast some boolits from a Lee 405 grain mold and they dropped 458 out of a brand new mold, I casted a few boolits and chucked them up in a drill with some rubbing compound and spun it in the mold, It now drops 460 right where I wanted it, not to mention they fall right out of the mold. I used straight wheelweights.

[corvette8n]

I use the Ranch Dog 420gr .460 Lee group buy mold
drops them at .460 using wheelweights.

You need to slug your rifle bore and cast a couple of thou. over that.

[Longwood]

Sunday I cast some boolits from a Lee 405 grain mold and they dropped 458 out of a brand new mold, I casted a few boolits and chucked them up in a drill with some rubbing compound and spun it in the mold, It now drops 460 right where I wanted it, not to mention they fall right out of the mold. I used straight wheelweights.
I am going to try that tomorrow since my new 457 405gr Lee drops 456 every alloy I tried so far but I usually start with wheel weights and add 40-60 or 50-50 solder. My barrel slugs 457 so I will try 458 to start with. One of the last five out of 40 keyholed on me today but I am pretty sure it was because of lead buildup in the barrel. All five hit the 6 inch bull at 100 yrds though and three were inside of 3 inches but not satisfactory for me.
I bought a Postell designed (for target shooting) 535 gr Lyman on ebay today and sure hope it casts and shoots better.

[peerlesscowboy]

Speaking of the Lyman .45 caliber mould designations...

The companies that make mass produced moulds each have an alloy which that company considers to be it's 'standard' for adjusting the diameter of their moulds.

Custom makers cut a mould to throw a certain diameter with the alloy the customer wants to use.

Lyman's 'standard' is (the fairly hard) Lyman #2 Alloy, so that tells you where they are starting out.
Lyman also assumes that the customer will run a cast bullet through a sizing die.
Lyman #2 alloy is hard enough to have some 'springback' so their sizing dies are a bit undersize. If you run a bullet through their #458 die, it passes through a hole closer to .457"...but because of the springback, it swells back up tp .458" for you.

As for the '457' mould designation (as I understand it), Lyman assumes .457" is the smallest a customer will want to use in a .45 caliber rifle.
So, their moulds are cut to throw a bullet of #2 alloy, which will not be seriously deformed if run through their #457 sizing die (with a hole closer to .456", but enough springback to return to .457").

Obviously, this means the moulds throw 'as cast' bullets that are larger than .457". How much larger depends on which of several cherries was used to cut a particular pair of blocks.

Frequently, there is a two-letter code after the number designation. Those letters (when present) often identify the cherry used to cut that mould. If somebody has a 457132 CH (for example) and it throws .458' bullets you may not want it for a (say) Pedersoli rifle with a .460" throat.
If somebody else has a 457132 CK which throws .460" (as-cast) bullets, then you know which cherry you want them to have used when cutting a mould for you.

Finding out which letters are right for you...and finding a retailer who has a mould in stock with the right letters on it...well, that's the quest.
CM
EXCELLENT explanation, and if I might be so bold as to add.........if you want to use the bullets at "as cast" diameter and yet be able to lube 'em in your lubrisizer just use the next larger nominal size sizing die. For example if the mould's dropping at .458" and you want to just lube 'em and not size 'em down, use a nominal (459) die.

John C. Saubak

[Larry Gibson]

I would also like to know the purpose of hollow base molds.

Hollow based bullets can have one of 3 purposes or a combination of them;

The HB allows the skirt to expand readily sealing the bore with undersize bullets that are not of groove depth, ala Minie style bullets for muzzle loaders.

The HB shifts the center of gravity forward to increase stability in lower velocity bullets. The .38 HBWC is an example.

The HB serves primarily to lengthen or maintain the bullets bearing surface and overall length to provide a consistent bullet profile. The Lee .45 cal 405HB, a replicant of the M1873 45-70 service bullet, is an example.

Larry Gibson

[steg]

I have all the Lee molds for the 45/70, and they all cast at .460, using WW's and a little Tin for fillout, now some of the molds were Leemented, but that was more of a polishing that any serious metal removal in the die. My Lee push thru sizer was opened up to .460, and thats more or less just used to remove excess lube, if I use Mule Snot, I shoot em as cast, with no leading at all either way....................................steg

[swatts1555]

Is my metal to hard if RCBS 45-70, 500 grain bullets constantly weigh 25 grains less than the mold weight or 475 grains.

[swatts1555]

Is my metal to hard if Lee 45-70, 500 grain bullets constantly weigh 25 grains less than the mold weight or 475 grains.

[swatts1555]

Is my metal to hard if Lee 45-70, 500 grain bullets constantly weigh 25 grains less than the mold weight or 475 grains. HELP.

[Larry Gibson]

"All Lyman and most Lee molds are .457. Lee do have 2 molds that are .459. Why?"

If one goes back to the origins of the 45-70 cartridges we find there was the 45-70 "Government" which in the M1873/M1884 TDs had bores of .45 with .005" deep rifling (as per the 1873 manual). Most common is TD bores of .451 - .454" with the .005 deep rifling. On the other hand the commercial 45-70 rifles of the day had smaller dimensions with .457" being the generally accepted bullet diameter for them. Also understand that at the time of the 45-70 development it was still a common thought that the bullets should "bump up" or obturate to fit the bore/grooves of the barrel. Thus it was common for the bullets for BP cartridges to be .001 - .003"+ smaller in diameter than the groove diameter of the barrels they were supposed to be used in.

The 45-70 was considered obsolete and "dead" when the .450 bores came in vogue for large or African game. Our own ".458's" followed in that genre and .458 - .459 became the common bore size. When the 45-70 was reborn the rifle makers went with and standardized the "new" .458 - .459 groove diameter as standard for the "modern" 45-70. As most of the older Ideal/Lyman moulds worked just fine for the modern 45-70 there was no need to change. I have had several Lee mould for the 45-70 and have yet to find one that casts undersize when and appropriate alloy and casting technique is used.

Larry Gibson

[Ohio3Wheels]

My Lee 457405 drops 420gr .460 dia boolits using 20-1 mix of cable sheathing and 50/50. Hopefully this week will let me get to the range and find out how they shoot in the Wizard.

Make smoke,
Curt

[John Boy]

Gerry, let's go back to basics ... what is the bore & groove diameter of you H&R? Measure it. Then identify what bullet weight - diameter and alloy you'll be using.
Now go to Accurate Molds and see what 45-70 molds are currently in inventory. If you see one you like, then you can order it with diameter and alloy you desire ...
www.accuratemolds.com (http://www.accuratemolds.com)

[Flexy]

Hollow bases wouldn't work very well with higher pressure loads (so high velocity would be impeded) as they will blow the skirts out and mess up both accuracy, and ballistic coefficient. Mainly used in midrange loads for pistols, and slower loads in rifles.

As I'm trying out some high velocity powders to achieve a smaller required amount of powder per shot... And not pursuing after high muzzle velocity. Just comes to my mind, that I get "high" peak pressures (according to Quickload) but my muzzle velocity is under 500m/s. Also, that peak pressure occurs at about inch boolit travel from the start of the shot. What do you reckon about accuracy and bc? Cant mess up the boolit that bad when it is still in the barrel? Just ordered a HB mold from MiHec...

[44man]

I have a great deal of experience with Minie' balls and in every case the boolit must still be a tight fit.
By lapping molds to get a better fit I went from missing a 4X4 board at 50 to hitting a swinger at 200 meters.
Thin skirts would flare at the muzzle so you can't use too much powder.
There is no reason to use a HB with smokeless powders.
Actually a HP is more accurate then a HB, shifting weight to the rear works better.
The shotgun slug had no spin so weight forward worked. Shuttle cock affect.