The other day I finally added a 4 5/8" Ruger BH .41 mag to the stable. Up until this point I have only been using 8gr of Unique behind a 215gr BBSWC for my M58. Now that I have the Ruger and will be doing some pig hunting I want to use the same bullet with 2400 for full power loads in the Ruger.

I referenced both my Lyman third edition cast bullet handbook and the newest edition of the Lyman pistol and revolver handbook. I am really surprised that there is such a big variation between these two books with the above mentioned bullet and 2400. The cast bullet handbook lists a max charge as being 18.8gr while the new pistol and revolver book lists 16.7gr.

I always thought that 18gr of 2400 was pretty much the old standby for a 210gr -215gr cast bullet in the .41 mag. Anyone have any idea why the big variation, and is 18gr of 2400 no longer safe? I have a hard time believeing 16.7gr is going to get the stated 1200 something fps listed in the new book.

I been using 17.0 grains behind my Baylou 215's. Not max but you do know when it goes off.
Alliant shows 19 grains for a 210 Gold dot jacketed. I am of the opinion you can use the amount for an equivalent jacketed bullet for a lead since the friction is less. Some books stop before max with lead bullets due to leading issues. Below is a cutpaste from Alliants online data.

Pistols and Revolvers
41 Rem Magnum
•210 gr Speer GDHP

Minimum OAL
(inches) Bbl Length Primer Powder Charge Weight
(grains) Velocity
(fps) Print
1.575 6 CCI 300 Unique 9.7 1,123 View this recipe
1.575 6 CCI 300 2400 19 1,223 View this recipe

I settled on 17 gr/2400 w/ 2l5 gr cast bullets many years ago; I use 17.5 gr w/ 210 gr jacketed bullets (these print to same POI at 50 yards in my guns). All w/ standard primers, Remington or Starline brass. I found going up just .5 gr in either of these loads began to show pressure in my three M57s.

Be careful on using the data from the Lyman book. Don't go by bullet weight alone. Some cast bullets have a lot more 'shank' in the casing and thus have less room for powder , potentially causing higher load density and pressure. The Lyman 410459 is a true "Keith-style' with a lot of mass in the long nose , but a short 'shank' because ol' Elmer wanted more powder behind in the case. Compress a charge safe with this bullet , with the longer body of most commercial 215 BB-SWCs and you could have dangerously high pressure.

I was told by a tech at St. marks that this is part of the reason that Blue Dot is not recommended. The Lyman data for Blue Dot is safe with the 220gr #410459 , but use that bullets max B-D charge with bullet with more shank in the case , ya get a compressed charge and bad things can happen.

It appears as though you are using data for the Lyman 410610 bullet. This discussion has come up several times before, not the exact bullet/caliber, but why don't they agree.

This is a fine example of how much can change between one source of load data to another, even if it's the same manual. Little things will have an affect on the test results, such as temperature and humidity, and who is doing the measuring is also a large factor. Then there is always the fact that they don't always use the same components and here is a perfect example of how much can change from one to the other. Did you happen to notice the primers used were different? Also, pay attention to the pressure and velocity reading they got between the two loads.

Your manuals are just a guide to get you started and will usually tell you so somewhere inside. Start low and work your way up to a safe level and if you change anything from the components you started with, do it all over again. And don't think you are getting what they got in the book, because you more than likely aren't.