Since december we've been collecting and likewise generating our own data for the 25-35 win. At this point we've put together almost 1300 loads (Ackley, Belding & Mull, Hodgdon, Hornady, Ideal, Lyman, Speer, Handloader + our own data). And most of the data hangs togther well (to use a technical term). As a scientist one might call it smooth and predictable. And in our data taking have found the generated data well behaved, ie, the cartridge isn't malicious. (Some cartridges are genuinely difficult to get good data for, the 25-35 is not one of them... actually quite the opposite.)

Our concern has to do with the 25-35 win data listed in the "Hodgdon 2004 Annual Manual" (we don't know if the same is true in the 2005 manual - don't have one yet).

Let me try to take advantage of the expression: a picture is worth a thousand words...

www.gmdr.com/levern/2535h4198no2004.jpg

This is a graph showing velocity as a function of powder weight, using H4198 powder in the 25-35 win cartridge, for various bullet weights. (from hornady manuals 1-5, hodgdon #23-26 - 30 years worth of manuals; plus our H4198 data). The traces are the pw vs v function for the bullet weights listed (and the source for that trace is also noted). As one can see and would expect: the lightest bullets generate the highest velocities using the largest loads. In this case the 60gr bullets with H4198 are driven with 21+ to almost 24 grains of powder, generating 2400 to 2700fps mv. Likewise, the 86/87 grain data, uses less powder, and generates less velocity; and likewise the 117 data. Two interesting points here: note that physics is physics, ie, it didn't matter if Hornady or Hodgdon took the data, the results were very close (look at 60gr and 117gr data, 20-30fps?); or even when we took our H4198 data (20fps slower than what hodgdon saw for manuals #23 - #26). This is what one might call coherent data.

The following graph is the same as above, but the H2004 data has been added -

www.gmdr.com/levern/2535h4198wH2004.jpg

Is there some new superman H4198 powder out there that I'm not aware of? Otherwise, it looks like they've trimmed all the max loads by 2+ grains; likewise the starting loads; and at the same time are getting velocities nominally associated with the untrimmed loads. Maybe this is what they actually saw... or another expression comes to mind: "To err is human; to totally f... it up beyond all recognition, still requires a computer."

We also take the above as a prime argument for not reloading from a single manual - just because it's printed, doesn't make it correct. We have like concerns with the other data therein listed.

He who dies with the most fingers... wins,
or,
know your data... before you use it!

do shoot straight,
greg
www.gmdr.com