Home Forums Reloading Handgun Reloading General question re cast bullet loading

When loading a cast bullet for which you can find no direct load data in the books am I correct that you can use load data for another cast bullet of the same weight/similar profile?

If so, when comparing several cast bullets of same weight/similar profile (but not identical to the one you've cast and want to load) I notice the min/max charges are different for each..


So.. which load data to start with??

It’s not just cast bullets you have to work around. I make my best guess based on experience and what data I can find, then start on the low side and try a couple. I use a chronograph and carefully inspect every fired case, then adjust the load and tease a few more.

Thanks Sam. I know that's the prudent approach. Still, seems a bit 'loose' somehow.
Just frustrated tonight reading the books and trying to find a start point for a few bullets I've recently cast. Reading online I find a lot of "Love these!" or "Great bullet" responses on the forums, but very little actual data.

You will get different numbers from different sources. For a given weight bullet of similar profile, there should be some overlap.

This isn’t an exact science. That’s why you always hear the old mantra of starting low and working you way up.

The more surface area of the bullet that contacts the bore when fired, the higher pressure you will get from the same powder charge. A heavier projectile will also cause higher pressure with the same powder charge. Further, the more space in the case the projectile takes up, the higher the pressure will be as well.

There are a lot of things to consider when dealing with ballistics.

If you give some specifics, somebody here will likely be able to give some real world experience.

Use jacketed data for the same weight bullet.

Full wadcutters excepted.

Why not list the bullet you're using...???

What’s the mold?

Quit making it simple. 😁

Pawing through my manuals I see discrepancies, some fairly significant, between cast and jacketed of the same weight with the cast pressures being more favorable. But in the case of the late issue Lyman manual the specific cast bullet mold is specified while the jacketed bullets are generic, so again it boils down to cautiousness on the handloader's part and the old protocol of "starting low and working up."

No doubt!

Had this conversation with a friend I had sent some casters to.

I told him to hold up the bullets, crimp groove to crimp groove.
In every instance the jacketed bullet seater deeper into the powder column, even if the cast bullet weighed 20 grains more.

It has more to do with depth into the column more than bullet weight and pretty much every common cast bullet (except full wadcutters) intrude much less when comparing. Intrusion is what jacks up pressures in handguns.

Gents,
Thanks much for your contributions.

Yessir! This is the exact point of my post.


Joe, I'll do that here shortly. What I'm hoping to discover is the overall approach that those of you with more experience than I use when facing this situation.





Hawk,
Right! Sooo... don't simply sub jacketed data for same weight?





Thanks again fellas for your help. Genuinely appreciated. I'm getting there, and I'd like to wrap my head around a safe and prudent approach to this situation as I'm fairly certain I'll come across it with regularity.

In any case, as examples, the two recent bullets that I'm currently hung up on are the Lee 358-158RF and the Arsenal 358-158KT as loaded for both .38Spl and .357Mag in an S&W 3.5" 27-2.

The Arsenal bullet is a 'Keith style'.. load data for a similar Keith is for a 170gr version of this, heavier than mine. In addition the similar 358-429 looks to be a bit longer..
When I compare my bullets to other same weight/similar profile bullets the charges all vary. Also, the designs of the other bullets may appear to take up more case volume, touching on what Hawk mentioned.


So... How do all of you approach this situation when loading??

Dan

Missed the point. When seated to the same point in the crimp ring the XTP base will be farther in the case increasing pressure by reducing capacity. I use jacketed data all the time for Keith style cast.

158 XTP and 158 MBC SWC, same load for both.

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Swifty,
Point taken, thanks.
Dan