Hi guys, I've been lurking on this site for years but thought I would finally join to get your opinion about something.
I'm developing a new load for my 300 Win Mag, I have a decent 180 gn TTSX but since it is only travelling at 2900 fps I wanted to speed it up a little bit. I've decided to go with the Barnes 175 gn LRX for the high BC, running H4831SC powder.
I loaded up 8 rounds, basically trying to find a safe max. Starting at 69.0 gr and working up in 0.5gn increments. I went and shot them today and have 2 questions.
1) this is the first time Ive had a chrony for load development and was allittle suprised. Some of the loads were actually slower than the previous although they had more powder. Is this common? reloader error? Chrony error maybe? here is my results:
69.0 - 2677
69.5 - 2766
70.0 - 2824
70.5 - 2812
71.0 - 2801
71.5 - 2923
72.0 - 2949
72.5 - 2867
2) this question is about pressure signs. With 72.5 gr i'm noticing a small amount of primer flattening. No stiff bolt, no cratered primers, no extraction marks. Would it be safe to keep increasing until I see some of these other signs. The reason I ask is because my last load wasn't the fastest yet my primers were quite flat. I was using 69 gr of IMR4831 which is well under the max for that load. I've attached pics of my primers.
Unshot, round primer
Some flattening, 72.5 gr H4831SC (0.5 gr past published safe max)
My previous recipe, 69 gr of imr4831, well below published max
I'm using federal 215 primers, which from what ive heard are softer than others. Should I keep increasing powder charges until I start seeing other pressure signs or should I keep it where it is? Im trying to get it well into the 3000's, closer to 3100fps if possible.