RCBS cast manual VS Lyman 4th cast manual

[hawkenhunter50]

Was doing some comparing of 38 Special loads between the 2 mentioned manuals. Seems for 38 anyhow the RCBS start loads are about where the Lyman max loads end.

Wondering if you guys think the RCBS is on the hot side or if the Lyman max is on the conservative side.

Also comparing the same bullets for example the 38-148-WC, the data for 38 is hotter than the same bullet in 357 in the RCBS.

Maybe the RCBS 38 data is somehow mixed up?

Any thoughts?

[Hi-Speed]

Difference in bullet type (even when weight is the same), hardness, cartridge overall length, primers, etc all can alter the pressure of a given charge weight…

[lotech]

The RCBS book came out in the mid '80s. I'd have to read through the book to find out for sure, but it wouldn't surprise me to find out the the data was not pressure tested. Lyman #4 cast bullet book was published about twenty-five years after the RCBS manual. I think most Lyman data is pressure tested which probably accounts for lower charges in some instances. RCBS probably deemed their published loads safe for guns in good condition. That's reasonable, but assumes the handloader has a good background in handloading, has read up on the subject in different manuals, and didn't get his handloading education off of YouTube or Internet forums.

Yes, the Bullseye loads (the only ones I glanced at) look suspect. Another good reason to have a bonafide handloading background so you can spot something questionable and also a good reason to have an adequate number of published reputable data sources.

[MT Gianni]

RCBS has some reduced H110 loads in their rifle section, even though Winchester says not to do this. I like the manual and find it useful but double check everything. I far prefer Ly 3 to 4.