View Full Version : difference in loading data ?
As a newbie reloader I have a question.I reload 9mm using win 231 powder.In my loading books it calls for between 4.4 and 4.8 grains for a 124 gr.fmj or rn.but for the Hp it calls for 4.4 max.What is the difference when both bullets weigh the same?I just ordered 200 hornady 124 gr XTPS and wanted to load a hot round.I was loading 4.6 for regular rn.Would it hurt to use the 4.6 when loading XTPS.Would .2 tenth of a grain make that much difference?thanks guys.Just to be safe I lowered the grains to 4.4 but am curious. sj
JHP data will usually back off a bit from the fmj data because the with the hollow point, the bullet can be longer and needs to be seated deeper into the case. Less case volume = higher pressure with the same powder charge.
Not all data is the sme, not all JHP or FMJ are the same. Every reloader should be using multiple manuals to derive safe powder charges & OAL. Unless you are using the exact bullet & OAL given in the manual, you have to extrapolate. As ZS said, longer bullets seated deeper raise pressure, in small volumn cases, quite a lot. Depending on powder used, a 0.2gr diff can mean you went from safe load to over pressure. Yes, it all matters. Newbs should stick w/ published data, but that means exactly. The XTP is not the same as the GoldDot or Berry's or lead.
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