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Old July 8, 2012, 10:43 PM   #22
Unclenick
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Join Date: March 4, 2005
Location: Ohio
Posts: 10,332
Marco,

That WC844 is H335 is something I got from the 2009 Hodgdon MSDS sheet, along with those for a number of other relabeled powders. They are in the table below. The current (2011) Hodgdon MSDS for spherical propellants no longer has the alternate names available, but the Winchester one availale (2009) still does. The only difference is bulk grade verses cannister grade. Hodgdon keeps back bulk lots that turned out to be extra fast and extra slow, then blends those with new bulk lots as need to adjust the average burn rate to within 3% of nominal, thus creating a cannister grade blend. I got that straight from the mouth of one of Hodgdon's technicians. You can call them and verify it for your own satisfaction. They also have held back lots that are exactly average burn rate for doing their load data development.

Code:
                   | St. Marks  |                        | Thales   |                      |
     Hodgdon       | Mil & OEM  |      Winchester        | (ADI     |  IMR                 |   
___________________|__Numbers___|________________________|__________|______________________|_
                   |            |                        |          |                      |
HP-38--------------|-- OBP231 --|- 231 ------------------|----------|----------------------|-
                   |   OBP124   |  AALite (WFL)          |          |
Titewad            |   OBP132   |                        |          |
Tightgroup --------|-- OBP242 --|------------------------|----------|-----------------------
                   |   OBP465   |  Super-Handicap (WSH)  |          |
Longshot           |   OBP473   |                        |          |
Lil' Gun ----------|-- OBP516 --|------------------------|----------|-----------------------
Hybrid 100V        |   SHP771   |                        |          |
                   |   SMP224   |  AutoComp              |          |
-------------------|--- WAA90 --|- WST ------------------|----------|-----------------------
H110               |    WC296   |  296                   |          |
HS-6               |    WC540   |                        |          |
-------------------|--- WC748 --|- 748 ------------------|----------|
H414               |    WC760   |  760                   |          |
H335               |    WC844   |                        |          |
BL-C(2)------------|--- WC846 --|------------------------|----------|-----------------------
H380               |    WC852   |                        |          |
US869              |    WC869   |                        |          |
-------------------|-- WMR780 --|- Supreme 780 ----------|----------|-----------------------
                   |   WXC170   |  WSF                   |          |
Clays              |            |                        |  AS30N   |
International Clays|------------|------------------------|- AS50N --|-----------------------
Universal Clays    |            |                        |  AP70N   |
H4227              |            |                        |  AR2205  |  IMR 4227 second source
H4198 -------------|------------|------------------------|- AR2207 -|-----------------------
Benchmark          |            |                        |   BM2    |
H322               |            |                        |  AR2219  |
-------------------|------------|------------------------|- AR2210 -|- IMR 8208 XBR --------
H4895              |            |                        |  AR2206H |
Varget             |            |                        |  AR2208  |
H4350 -------------|------------|------------------------|- AR2209 -|-----------------------
H4831              |            |                        |  AR2213  |
H4831SC            |            |                        | AR2213SC |
H1000 -------------|------------|------------------------|- AR2217 -|-----------------------
Retumbo            |            |                        |  AR2225  |
H50BMG             |            |                        |  AR2218  |
-------------------|------------|------------------------|- AR2215 -|- IMR 4198 second source
                   |            |                        |  AS25BP  |- IMR Trail Boss
Don't put too much faith in TM-43-0001-27. It's just intended to provide examples, not to serve as a book of load recipes. Moreover, it has more than one error in it. For example, it says M2 Ball and M72 Match have the same 50 grain charge of IMR 4895. The actual historic average charge of IMR 4895 in M72 was 47.5 grains. You'd expect a smaller charge with a heavier bullet, anyway. You can see it in the last years in the table of National Match ammo loads below. Note that from 1962 on, Lake City gets quite a bit of velocity variation with different lots of IMR 4895, with lighter charges producing more velocity some years than heavier charges did in other years. That's all about lot burn rates differing. There is no one fixed recipe because bulk powder varies too much by lot to allow it.

The way the military develops a load is the bullets have to reach a certain velocity window within a certain pressure profile. If a particular bulk lot of powder cannot achieve that, the lot is rejected for use in that load. On another board a former Aberdeen Proving Grounds Test Director described how, in the 70's, they got two lots of WC852 (H380) for M2 Ball ammo, and how one lot would achieve the required velocities without the muzzle pressure getting too high for the Garand, but the other would not. They used both, but the latter lot was qualified for machinegun use only, and not for use in Garands. Unfortunately the DCM issued much of the machine gun stuff for Garand use during the 80's. As a result some op-rods met their maker prematurely. I still have some of those rounds. You can tell them by pulling the bullets and weighing the charges/ The average charge weight in the machine gun ammo is over 56 grains, while the good stuff is more like 53 grains, IIRC (haven't had any for awhile and don't recall an exact number; just that it was several grains lower).

What you have is pull-down powder from ammo deemed to be getting too old for stockpiling, so you know it qualified correctly at one time or it would not have been loaded in the subsequently pulled-down cartridges in the first place. But you just don't know exactly what charge weight they chose for that specific lot.

Bottom line, if you depend on recipes, only cannister grade powder will be sure match them well. Bulk lots may or may not. The cannister grades are indeed adjusted to about the average seen for the bulk grades, but being adjusted, they vary less from lot to lot.

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