Cast bullet in place of jacketed. Dangerous?

[Winger Ed.]

I'm asking because I cast a bunch of 158grain bullets but they all came out in the 160grain range.

Don't worry about it. That's normal.
The mold is listed at 158 with an exact alloy.

If you cast it with a softer, or harder one, the weight will be a little bit different.
I cast with a .45 405 FP mold. At the old, black powder, trap door speeds,
I use a alloy that is pretty soft, and they come out at 424 or so and I still use the 405 data.
It works fine, and so will yours.

Just use the 158 cast load data, take the normal precautions, and live happily ever after.

[gwpercle]

I could not find an answer to this question with any quick Googling so I'm asking here.

Can you substitute a cast bullet in a recipe that calls for a specific jacketed bullet as long as the mass of the bullets are the same?

I understand that driving a cast bullet to jacketed speeds will cause leading very quickly and that it may not work worth a damn because of many different factors involved, but will things explode?

I'm asking because I cast a bunch of 158grain bullets but they all came out in the 160grain range. I can't find a recipe in my books for a cast 160grain bullet with the powder that I want to use, but I can find one for a jacketed 160grain. Would there be any harm in using the jacketed bullet recipe with the understanding that it may not be ideal?

Don't worry ... this happens all the time ... 158 grain mould drops 160 grain . First ...it's only two grains ...So you would be much better off using the data for the 158 grain cast boolit than a 160 gr, J-word data . The charges for J-words are usually higher than what you need for cast .

I have a 160 gr, mould Lyman #358432 WC ... and I simply use data shown for 158 gr . SWC .
Most moulds will cast a little little lighter or heavier depending on exact alloy , you will not find data on every weight variance ... If the mould says it's supposed to be 158 gr. SWC then use the data shown for 158 gr. SWC in the Lyman manual .
But do not substitute J-Word data for cast boolit loads except when no other data is available and then start at the Starting Load and work from there .

Here's a little hint ... don't get all OCD-Anal about weighing boolits ... it gets you gray hair and lots of lost time ... Cast em and Choot Em ...
...unless youre shooting for Money or Trophies !
Gary

[Larry Gibson]

"BUT:

1. - I've been doing this since 1965 and my experience has told me that cast loads will always be at a lower pressure and higher velocity than a jacketed load with the same powder charge because no lead alloy has yet been made that equals the hardness of a jacket. Well lubed lead bullets tend to slide through the bore easier/faster than jacketed bullets of the same weight and powder charge."

My thoughts and "experience" also.....until I started testing such.

A couple examples that demonstrate this just ain't so;

357 magnum ; 7 gr Unique in Winchester cases , with WSP primers with three different bullets loaded to the same seating depth. All loading powder charges thrown consecutively and loaded consecutively. Pressure tested in a 10" Contender barrel via an Oehler M43. Pressure testing done with in the same hour with time between tests to cool the barrel, clean the barrel and fire two foulers for each load.

With a Speer 158 gr JSP; 32,500 psi
With a 358156 at 162 gr; 32,200 psi
With a TL358-158-SWC at 159 gr; 34,100 psi

30-30 Winchester; 28 gr IMR 3031 in FC cases, WLR primer with 3 different bullets all loaded consecutively at the same time. Pressure test in 21" Contender barrel via the Oehler M43. Again, the tests conducted consecutively on the same day with in one hour giving time between test to cool the barrel, clean the barrel and fire two foulers.

With a Winchester 150 gr RNPP; 34,100 psi
With a RCBS 35-150-FN; 34,600 psi
With a Lee C312-150-WFN; 39,900 psi

That's just a couple examples showing the opposite of what many if not most of us have believed. I can also show other examples and can also show examples where the supposition is correct.

Point is, it isn't always correct to assume cast bullets "will always be at a lower pressure".

[P Flados]

Larry,

Thanks as always for the real factual data. So many people propagate reloading "myths" leading to a lot of misinformation getting treated as fact. Having you come along and show us what is real is just so much better.

The actual numbers seem strange (Lee consistently higher than Jacket or traditional mold vendor). For now I will just mentally chalk it up to "different shapes can give different results". Any chance the Lee 30 cal had significantly less jump before engaging the rifling.

Given your pressure results, I assume all ammo extracted great and all primers look perfectly normal. I also assume that if you pushed the loads say 15% past SAAMI limits, the extraction and primers would still be in the "normal" range of things.

[Larry Gibson]

"Any chance the Lee 30 cal had significantly less jump before engaging the rifling."

Perhaps because, given that was a 30-30 cartridge the bullets were seated to the crimp groove and a roll crimp applied. The crimp was adjusted to not buckle the neck/shoulder with the jacketed bullet. The crimp was not readjusted for the cast bullet but remained consistent for all three bullets. Same with the 357 loads. The assumption being these cartridges are loaded to the crimp groove from the bullet in question the OP inquired concerning the 38 SPL or the 357 Magnum(?).

As to flattening of the primer being an indication of pressure; If headspace [cartridge to chamber] is not an issue then the flattening of the primer is an indication that there is pressure. With a given primer, the flatter the primer the higher the pressure. However, it does not really indicate how much pressure or whether the pressure is excessive. In rifle/cartridge combinations safely capable of 60,000 psi the primers are going to be much flatter than the same primer fired in the same rifle/cartridge/powder at 55 - 57,000 psi. Which gives consideration to the burn rate of the powder and the rise time to peak pressure also influence the "flatness" of primers.

BTW; a pierced primer is also, and more often than not, an indication of a firing pin problem not excessive pressure for the cartridge/firearm used. I've seen many ill fitted/formed firing pins pierce primers in low pressure loads in both rifles and handguns. On the other hand, a blown primer [primer pockets is swollen and fired primer drops out] is definitely a sign of very high, excessive pressure. In revolvers, sticky extraction is usually the first sign of excessive pressure. But keep in mind that sticky cases on extraction can also, and is frequently, caused by too soft brass for the normal top end pressures for the cartridge. Thus sticking with actual pressure tested data is best for most reloaders.

[farmbif]

over the years ive learned not to just assume anything. as previously stated there are many variables. If your just starting to cast your own bullets and load your own ammo do yourself a favor and get the Lyman cast bullet manual and there is a plethora of great info you can download at .
http://www.lasc.us/ArticleIndex.htm.
there is lots of great info here and lots of people who's lives are devoted to the sport but in-between there are also some that try pushing the envelope a bit too far for me to try their loads in any of my guns. I'm conservative and want to keep my eyes, hands and guns intact.
stay safe and always work your loads up starting with lowest published powder charge. affording the cost of the powder, primers and lead to do this is all part of the sport.

[Castinator]

You can use jacketed data for a basis. Just start low and chrono the rounds to make sure that you are getting the velocities that you expect.
Ultimately, the thing to keep in mind the case volume. So if your COL is the same and the bullets are a similar shape, the data is probably pretty close. If your COL of your lead bullet is shorter, you need to start with a lower charge because the reduced case capacity will generate higher pressures.

Bullet length matters. Your COL will be the same no matter what if you don't adjust the seating die. The longer the bullet (at same COL) the less case capacity. So I look for data on jacketed bullets that have identical lengths of the cast bullet (and same rear profile, e.g., not boat tail). This is a consideration *before* I buy a mold; will there be any data for it?

[dogdoc]

A chronograph is your friend since velocity is related to pressure. As long as my velocity is more or less in line with book values(allowing for different barrel lengths) , I do not worry too much. I also look closely at built shape and most importantly how much of the bullet is in the case. (Not necessarily oal since bullet profile can be so different)

[Larry Gibson]

A chronograph is your friend since velocity is related to pressure. ......

Only if you are comparing loads using the same powder, and then, with the same lot of powder. For example (extreme though it may be it makes the point) 35,000 psi with Bullseye will have a lower velocity than with 2400 given the same cartridge and bullet. Upping the velocity using Bullseye to equal the velocity of the 2400 load will give some serious over pressure.

[Savvy Jack]

The only real concern I have seen during my testing is that some designs created more pressure than other designs. I did not do enough testing, like Larry, to find or even think I could find an answer.


Test #/POWDER CHARGE/POWDER/BULLET/Manufacture/Velocity FPS/Est PSI/Est CUP/F
9/25gr/Reloder 7/240 LRNFP/3D LRNFP/1,300/9,613/<11,500/38
68/25gr/Reloder 7/240 SCW/Acme Hi-Tek/1,420/14,542/<17,500/36
67/25gr/Reloder 7/240 DGHP/Speer 4455/1,350/15,248/<18,500/36
39/25.3gr/Reloder 7/240 LRNFP/Lee 3 Crimp/1,446/15,279/<18,500/39

[dogdoc]

Only if you are comparing loads using the same powder, and then, with the same lot of powder. For example (extreme though it may be it makes the point) 35,000 psi with Bullseye will have a lower velocity than with 2400 given the same cartridge and bullet. Upping the velocity using Bullseye to equal the velocity of the 2400 load will give some serious over pressure.

Yes, I am definitely comparing loads with same powder. If I have to substitute a bullet of similar or same weight in a load that no data exist for that-exact bullet(common with our cast bullets), I try to match the seating depth so that the volume in the case is similar. I then use my chronograph to make sure velocity is in the ballpark or the original load(accounting for barrel length). The chronograph is our best tool if we do not have pressure testing equipment like you do.

[P Flados]

The Chrony used as described dogdoc is a good tool in many guns. Unfortunately, it is much less useful with revolvers.

[Larry Gibson]

Yes, I am definitely comparing loads with same powder. If I have to substitute a bullet of similar or same weight in a load that no data exist for that-exact bullet(common with our cast bullets), I try to match the seating depth so that the volume in the case is similar. I then use my chronograph to make sure velocity is in the ballpark or the original load(accounting for barrel length). The chronograph is our best tool if we do not have pressure testing equipment like you do.

That's the way to do it.