10mm load help needed


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reflex
March 14, 2010, 09:57 AM
Hello,
I'm starting to learn how to load 10mm and have run across an issue that I do not understand and need some help. The powder I'm using to start off with is the Winchester 231 which is now manufactured by Hodgdon. The bullet I'm using is a 180 gain Copper plated RNFP. The load data in my Lyman 49th lists data for a 180 grain jacketed HP is start at 5.9 with a max load of 6.6. The load data on the Hodgdon website lists data for a 180 grain JHC is start at 5.2 with a max load of 5.8. The difference in load weights is striking to me unless I'm missing something and that would be is there a difference in powder weights using the same powder but with different bullet types? I would think that a 180 grain HP would take the same weight powder as a 180 grain RNFP or 180 grain JHC but I new at relaoding and wanted to ask more experience loaders. Thanks for any help.

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GJgo
March 14, 2010, 11:05 AM
The first thing to understand is that different types of bullets of the same weight will have different length bearing surfaces & material hardness so it will take different amounts of powder to reach the same pressure.

The second thing to understand is that most companies have load data slightly different from other companies. This can be due to the items above, brass type, testing method, powder lot number, how hot it was the day they tested, etc.

The best thing to do is to consult a couple sources, look for the trends, start low and work up in your gun.

jmortimer
March 14, 2010, 11:44 AM
Off "Load Data" site, Winchester lists max load for 180 grain "JHP" as 5.8 grains. Hornady "XTP/ HAP/FMJ" as 6.3 grains max. Sierra 180 grain "JHP" is 5.6 grains. You will find that loads will range as GJgo said. No big deal but 231 is not the powder I would pick for 10mm.

loadedround
March 14, 2010, 11:55 AM
I load and have been loading for 10mm auto for a few years now and can understand your frustration. I would suggest starting at the lower stating load and working up carefully, watching closely for pressure signs. However in my opinion, 231 ie a little to fast for the 180 gr jacketed bullet in the 10mm. My favorite useful load for this cartridge/weight combination is 9.0 gr of Blue Dot that is actually 1 gr under the starting load listed in the current Speer #14 Manual. According to my notes the original starting load for Blue Dot was 8.0 gr. I'm shooting this load in a Colt Delta Elite.

GJgo
March 14, 2010, 01:04 PM
FWIW, I load 180gr XTPs in my 10mm & I use AA #9. AA #7 would be another good choice.

MachIVshooter
March 14, 2010, 03:13 PM
No big deal but 231 is not the powder I would pick for 10mm.

+1

231 is a good powder for smaller cases, like .380 and 9x19. 10mm, with case capacity and pressure similar to .357 Magnum, likes slower powers, such as Blue Dot, AA#5/#7 and IMR-800x.

I personally use CCI 350 magnum primers and IMR-800x.

reflex
March 14, 2010, 04:38 PM
thanks for all the responses. being new to the reload and being constrained by what the gun shop guy had in stock he suggested 231. Based on past experience in other matters I kinda took it for granted that he knew what he was talking about. In his favor was the fact that it was listed in the Lyman 49 manual as a possibility. I only load .223 (using 2230, again shop guy) other than 10mm so this 1 lb jar is gonna have to make due for a while. But I appreciate all the other recommendations. I'm still really new and have only loaded 2 rounds using the Lyman suggestion of 5.9 start. I think my next move is to load 2 or 3 each at 5.2, 5.4, 5.6 and then go to the range, start with the lowest and see what happens. Hope I make it back home. Again, thanks to all for the replies. I'm sure I'll have more questions in the future, if everything works ok :)

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