Is there a "rule of thumb"

[Dennis6474]

For using lead cast bullets and the load data for jhp. Same weight bullet just have the data for jhp and want to load lead using the same powder. I know it won't be simple, right?

[Scorch]

Yes, there is. The rule of thumb is: don't try to invent your own loads.

Lead is different from jacketed. It gas custs easily at higher pressures, it doesn't need hot loads to get it started in the barrel, and it generally can't be pushed as fast (somebody will come along and say they've loaded lead to 2,000 fps, but you had better be good at removing leading if you do that).

So:
Lower pressure, milder velocity loads.
Bullets generally .001" larger than bore diameter.
Velocities around no higher than 1,000 fps.

[Unclenick]

As you say, not simple. A lead bullet takes less force to push into the throat and barrel which lowers start pressure, though degree of crimp can make a bit of difference there. The same weight lead bullet loaded to the same COL as a JHP will typically be a bit longer than the JHP due to the lube grooves and a more pointed nose, so it seats deeper, which reduces powder space, and that tends to raise pressure. Sometimes that problem goes away because the lubricated lead is easier to push out of the case, so the primer can start unseating the bullet before the powder burns, making the powder space bigger. This is especially common in the short powder spaces in common pistol cartridges. As a result, if you look at load data in Hodgdon for 200-grain LSWC and JHP, you find some powders have a higher maximum for the JHP and some have it higher for the lead.

So, the answer is, we don't know until we try. This article by Allan Jones shows about 30% of pressure difference can be seen with same-weight bullets due to their construction differences. There is one board member who will tell you only the weight matters and nothing else. Despite pointing him to that article several times, he maintains willful ignorance on the matter, so ignore him if he says it again here.

The issue is further complicated by the fact many load manuals limit the maximum load so the pressure won't cause extreme leading or deform a bullet too far, so you have that limitation, too.

Your best bet is always to look up data for the exact bullet you have. If you can't, take the maximum jacketed load and reduce it 20% for the lead starting load and work up. It will probably be too light and may go all the way past the JHP max. Or it may not.

[Nick_C_S]

Dennis6474,

Now that Scorch and Unclenick covered the generalities; can we have some specific info so we can make sure you're going down a safe and practical path?

Cartridge?
Specific bullet/weight?
Powder?
Primer?
The specifics of what data you do have?

All that sorta stuff . . .

We'd be happy to give further guidance.

-Nick.

[gwpercle]

There is no rule of thumb for adjusting data for jacketed bullets to data for cast bullets .
Just way too many variables for a blanket statement rule to cover semi-auto pistol , revolver ammo and rifles . I've been casting bullets and reloading for over 50 years and have read and studied the subject extensively . The best thing to do is use data developed for either cast or jacketed bullets . There are a lot of manuals and some info online . Lyman and RCBS have cast bullet manuals that deal only with cast .
Hornady , Speer , Accurate Arms have data dealing with both lead and jacketed .

There is just too much published information available out there to go second guessing a safe load derived from jacketed data for cast bullet loading...strange things can happen with some powders . It's not worth the risk... This is one hobby that the danger of blowing something up is very real .

You have questions about a load...get specific and give us the details of what your wanting to do , caliber , bullet , bullet description , gun ...the more info the better we can help answer your question...you can never have too much info !
Gary
Gary

[Blindstitch]

Follow the rules or you won't have any thumbs?

[USSR]

Dennis,

If you're loading lead bullets, due to the lack of good lead bullet data in current load manuals, old load manuals are a godsend. If you search the internet you will find some downloadable old load manuals with what you are looking for.

Don

[Dennis6474]

I was afraid it wouldn't be simple. I guess I knew most of what you all were pointing out. I was looking for a starting point.

This is a .357/.38 semi-wad cutter lead cast from wheel weights with some tin added. 140 grain Lee mold run through a sizing die and lubed with alox. I thought that Unique would be a good powder with CCI standard primers (not magnum primers).

I searched for a load that I could start with but could not find one for that 140 gr. bullet. I am sure that I can start low enough not to endanger me and I want to keep it below 1,000fps to cut down on the leading. Loading for .357 2 inch barrel and .357 6 inch barrel.

[Aguila Blanca]

Please stay on the topic and resist the urge to post attacks on other members, or this thread will have to be closed.

[reddog81]

The Lee 140 SWC has a tiny nose and long bearing surface. The amount of bullet seated in the case is pretty close to your average 158 grain lead bullet. I’d use lead 158 grain data as a starting point.

1,000 FPS shouldn’t be difficult in a .357 case. 1,000 FPS would be pretty hot for a .38 Special load. My favorite load is 4 grains Unique in a .38 Special case. Very accurate and easy to shoot. This load is probably closer to 800 FPS though.

[Blindstitch]

online handbook.
https://drive.google.com/drive/folde...nlfbXpRYlRTdXM

[buck460XVR]

Originally Posted by Dennis6474

For using lead cast bullets and the load data for jhp. Same weight bullet just have the data for jhp and want to load lead using the same powder. I know it won't be simple, right?

There is so much tested and published data available online nowadays, that anyone with access to a computer and the internet, can go to a powder/bullet manufacturer website and get safe and viable data. Most bound reloading manuals have both lead and jacketed data. It is actually quite simple. There is no reason anymore for claiming data is not available. If it is not, odds are, it is not viable and safe.

[stinkeypete]

My copy of “complete guide to handloading” (sharpe, 3rd ed. 1953) has information on the development of the .357 as Mr Sharpe aided Col. Wesson in the development of loads. The comments are quaint by today’s standards, about “...the most powerful revolver cartridge in the world today,”

The warnings that “if care was ever needed in the reloading of a revolver cartridge, it most certainly applies to this number. The handloader will do much better to use these cases and load standard .38 Special charges.”

For 145 Bond B bullets (I have no idea what those are, can anyone help us out?) Sharp has:
3.5 g Unique at 730 FPS, 4.5g at 905 FPS and 11,000 cup and 5.3 g at 1030 FPS and 15000 cup (max load, old standards, that may be considered “+p” now)

The Lyman Pistol and Revolver Reloading Handbook (1994) has .38 special loads:
141 g. Linotype wadcutter Unque:
3.8 g at 757 FPS 10,300 cup and 5.3g at 1013 FPS and 16,700 cup (max! Danger etc)
146 g Linotype round nose Unique
3.7 g at 652 FPS 9,000 cup and 5.4 g 928 FPS and 15,900 cup

For .357 Magnum loads
141 g. Linotype wadcutter Unique:
5.8 g 960 FPS 1460 cup and 7.9 g gives 1289 FPS at 40,300 cup

133g Linotype semi wadcutter, Unique
6.2 g 1006 FPS 18,300 cup and 8.6 g gives 1356fps at 40,300 cup

Heavier than this, Unique is not listed as a powder, perhaps it is outclassed (I used to use 2400, it was originally loaded with a special kind of 2400, per Sharpe... bullseye is a broad range powder too, as is imr-4227 and blue dot)

I include that data so you have a rough estimate of your margin of error and the safety factor your strong modern .357 revolver may afford you.

Personally, I would not hesitate to try 4, 5 and 6.0 g unique as an approach to your goal of a subsonic accurate load for a modern .357 revolver in good repair. 6 grains is 76% of a “max load” and pressure should be about half of maximum.

What is clear to me from reading Sharpe and looking at the data- the pressure in .357 magnum grows exponentially or faster as one adds powder. The case has the volume to allow catastrophic loads or mistaken catastrophic double charges with some powders, so use care, start low, don’t blame me if you blowed yourself up, etc etc

I happen to think 140 g humming along subsonic and accurate is a dandy load for a confident pistolero who has nothing to prove and is not attempting to hunt big pigs.

[T. O'Heir]

Using lead cast bullets and load data for a JHP, or any jacketed bullet, will result in a leaded barrel. The hardness of a cast bullet won't make any difference either.
"...want to load lead using the same powder..." That's totally doable. There's lots of data using the same powders for cast and jacketed. Just not the same data.
"...I’d use lead 158 grain data..." 18 grains is waaaay too much difference. Especially as there is cast, 140 grain, data, for both .38 Special and .357, on Hodgdon's site. Hornady Cowboy bullets are factory cast.
"...with CCI standard primers..." The primer used has nothing to do with the cartridge name. Despite Hodgdon saying to use 'em for .357 Mag(they also ran their .357 tests with a 10" barrel. And their .38 testes with a 7.7" barrel.). Magnum primers are about the powder used and nothing else.

[44 AMP]

Using lead cast bullets and load data for a JHP, or any jacketed bullet, will result in a leaded barrel. The hardness of a cast bullet won't make any difference either.

I disagree.

SOME data might, to say it all will is a gross overstatement. Leading involves bullet hardness, velocity and fit to the barrel. It's a balancing act, and when one or more of those factors is "out of balance" with the others, you get leading.

Considering that the majority of cast bullet and jacketed bullet data OVERLAPS, and only differs on the high and low ends of the range, the blanket statement quoted is inaccurate.

The biggest reason for the difference in lead vs jacketed data from different sources is the huge difference possible between lead bullets, compared to the much smaller difference between different jacketed bullets of the same weight.

A lead bullet, lets say a 158gr .38 cal (just to pick one) can be anywhere from dead soft/swaged to hard cast, and that makes a difference in your load, (and in leading). A 158gr jacketed, has a much smaller range of variance, in jacket hardness. All different designs can vary in bearing surface, of course, but the range of jacket hardness between makers is much smaller than the possible variance in the hardness of lead bullets.

This is a .357/.38 semi-wad cutter lead cast from wheel weights with some tin added. 140 grain Lee mold run through a sizing die and lubed with alox. I thought that Unique would be a good powder with CCI standard primers (not magnum primers).

I searched for a load that I could start with but could not find one for that 140 gr. bullet. I am sure that I can start low enough not to endanger me and I want to keep it below 1,000fps to cut down on the leading. Loading for .357 2 inch barrel and .357 6 inch barrel.

Unique and standard primers is a good choice.

FOR EXAMPLE ONLY
The 1970 Lyman manual shows 4.0gr Unique as their starting load for both their 141gr cast and 158gr cast bullets. 158gr Jacketed starts at 5.5gr Unique. These are listed in the 750-800fps range from a 5" test gun.

Every gun and load combination can be different. Your bullet is not their bullet, your gun is not their gun. USUALLY things are close enough so the data is a useful GUIDELINE. But not always.

Different people's data for jacketed and lead bullets can be quite different, or can be nearly the same. You'll have to judge what applies, and how much for your self, by CAREFUL testing.

That same old Lyman book shows 158gr lead starting at 4.0gr and jacketed at 5.5gr, but both bullets listed max is 8.0gr. With the jacketed slug doing 1170fps and the lead one 1250fps!

This does not mean you will get exactly what they got. This does not mean anyone/everyone else doing load testing will get what they got. It only means it is what they got with what they tested.

GUIDELINES
not laws...
hope this helps shed some light on things for you...

[Dennis6474]

Thanks everyone. I have what I needed and that is a bunch of good info. I had looked everywhere on line and there seems to be a lot of variations between the manufacturers on the loading between lead and jacketed. I know that I can load starting low but all this info shortened my learning curve.

Thanks again, I have never been disappointed with this forum. Sometimes it can also get pretty lively:>)

[reddog81]

Originally Posted by T. O'Heir

Using lead cast bullets and load data for a JHP, or any jacketed bullet, will result in a leaded barrel. The hardness of a cast bullet won't make any difference either.
"...I’d use lead 158 grain data..." 18 grains is waaaay too much difference. Especially as there is cast, 140 grain, data, for both .38 Special and .357, on Hodgdon's site. Hornady Cowboy bullets are factory cast.

Everything quoted above is wrong and is why asking for loading advice online can be troublesome. The load data for cast and jacketed have overlapping data most of the time. Hardness of the bullet makes a huge difference when it comes to leading. Hornady's bullets are swaged. The Lee 140 SWC has as much of the bullet seated inside the case as most 158 grain bullets. This is a more important factor than weight when determining which load data to use for a specific bullet.

If you look at the 140 .357 Mag Hornady cowboy load you'll see the hottest load load is 907 FPS with a pressure of 12,200 PSI... This load overlaps with the 158 LSWC .38 Special data and is even lower than the .38 Special data. Not real helpful...

[Unclenick]

If you read the Second Edition of Lee's Modern Reloading you'll find proof that bullet hardness is a significant factor in rifle accuracy and a method of figuring out what pressure can be withstood by what bullet hardness before distortion occurs and, frequently, leading starts to occur with it. There are other factors with handguns sometimes that cause a bullet soft enough to distort under firing pressure is actually helpful to accuracy, but that's where bore constrictions exist, particularly back where the barrel screws into the frame. If your bore and chamber throat(s) are in perfect condition and have ideal relative diameters, the hard bullets will generally do better about resisting leading.

[Grey_Lion]

2 things seem to be missing in this thread -

Powder-coating of cast rounds.

Powder burn heat.

I have fired thousands of cast rounds through my Glock - had fun with leading - did a lot of research online after a few long posts here.

Buy a used toaster oven and powder coat your cast rounds - then pass them through a sizing die and your leading issue will virtually cease to exist unless you have an extremely oversized projectile.

If you don't want to powder coat ( it's EASY and cheap - do it ) then gas checks may be what you want to get into, but that requires molds designed to take gas checks plus you have to make or buy the gas checks and you'll still experience some leading albeit a lot less than you would without gas checks.

Moving on to powders. I like H Titegroup for my FMJ and JHP. BUT - it burns hot and when you use it for naked cast rounds you tend to bring the butt of the cast round to the melting point in your barrel which can result in heavy leading and a smokier discharge. Once I moved away from Titegroup and went to HP-38 powder for my cast rounds, leading reduced and there was less of a smoky discharge. Titegroup burns hot enough to scorch powder-coating as well giving you a lovely smell on the firing range of cordite mixed with burning plastic. HP-38 is better.

Thats several thousand rounds of my personal experience with cast .40 S&W through both a stock glock barrel and an after market lone wolf barrel.

I have a special way of removing leading, but Uncle Nick isn't fond of me posting that - but you can look it up in my old posts.

[Unclenick]

Originally Posted by Grey Lion

...it burns hot and when you use it for naked cast rounds you tend to bring the butt of the cast round to the melting point in your barrel

There's something of an old wive's tale in the idea of melting a bullet with propellant gas heat. Hot powder burn is generally associated with high peak pressure and a greater amount of lead is gas-cut from the bullet base during gas bypass before the bullet obturates the bore (if it ever does after being gas cut). Higher peak pressure also increases peak acceleration causing the bullet diameter to bulge outward against the bore harder, increasing friction.

Gas cutting impact plates lead dust on the bore, and that is the build-up people often think has "soldered" itself to the bore. I have a front sight extension on a .22 target pistol that gets extreme amounts of lead buildup on its underside due to lead splatter from gas cutting by muzzle gas blast. I have to carve it off with a pocket knife intermittently, and I can see how someone would think that was soldered.

The reason gas melting doesn't occur is a bit complicated, but it involves the fact the metal surface is a much better heat conductor than the gas is, which means a temperature gradient develops across a short thickness of gas at the surface of the bullet, preventing it from ever seeing the peak gas temperature. You can calculate this via the thermal effusivity of the gas and bullet metal or use a time-stepped FEA program to see what happens during the millisecond the bullet is in the barrel, but the bottom line is the bullet surface sees temperature rise from the gas that is measured in tens of degrees, not hundreds. It is much less temperature rise that it experiences from its friction with the bore. The millisecond time frame is so short, its sort of like passing your finger through a candle flame without getting burned, only the exposure is much faster, and the gas is at a higher temperature. But the same principle applies.

[Scorch]

This is a .357/.38 semi-wad cutter lead cast from wheel weights with some tin added. 140 grain Lee mold run through a sizing die and lubed with alox. I thought that Unique would be a good powder with CCI standard primers (not magnum primers).

OK, I have been reloading for 45 years, and I have loaded a lot of cast 38 and 357 loads, most with Unique. So I suggest getting a Lyman reloading manual, there are loads for both jacketed and lead bullets with a variety of powders. I don't think the Lyman manual is a great manual, but it does have a lot of lead bullet data which is harder to find these days. But you're on the right track with lead and Unique!

[USSR]

The millisecond time frame is so short, its sort of like passing your finger through a candle flame without getting burned, only the exposure is much faster, and the gas is at a higher temperature. But the same principle applies.

Exactly, and worth repeating.

Don

[Dennis6474]

Thanks all. After all this great info I have to tell you that I was not looking for a particular load. Although I acquired a lot of knowledge with that question. I am simply looking for a load that is accurate, subsonic and that I will get the minimum leading.

I found it and it works pretty good. As accurate as I need and pretty inexpensive for practice. Of course the recoil and noise is less but my old arthritis hands can take an afternoon shooting without costing an arm and leg.

Sorry if it stirred things up.

[Unclenick]

No problem. The "stir-up", to the extent there was one, is typical. Threads almost always have a tendency to drift a bit as one answer makes someone else think of something tangential to it that they want to bring up. We try not to let that go too far, but it is normal for there to be some.

[Kevin Rohrer]

Check reloading manuals like Lyman #50 and you will see the difference.