404bearslayer
(.300 member)
14/02/10 03:18 PM
Re: Best magnum rifle primer for large cases

450-366,

I don't doubt your observations. The above mentioned tests were done with regular Norma powders (Norma did the test). Might be quite different with other powders - with primers you simply have to do chronograph tests to see which ignite a particular powder/bullet/case combo best. I have even observed differences depending on how hot a load was - certain primers worked better at hotter loads, others were better for soft loads. However, your info must have averaged the pressure / velocity values over the entire temperature range. I have shoot Fed 215 and CCI 250 (and WLRM) in comparison at ambient temperature and the difference in velocity was usually around 15-30 f/s, never more. In my .404, the CCI 250 gave actually better velocity then the Fed 215 (powder was H 4350). With Norma 203-B and a light bullet, it was the other way around, but the difference in speed and pressure was not large. I suspect you might have misread the data. I can think of no primer that can make a load 50 % faster then with another primer ... .

Something that surprised me personally once: Across all calibers I shoot, the Fed 215 was best for Bofors powders (Alliant / Norma / Rottweil), while CCI and RWS worked best with Hodgdon /ADI powders. I had therefor basically stopped using WLRM as they never got me the low velocity spreads I was getting with the other primers. Well, in order to duplicate the Hornady Light Magnum loads for my .30-06, I needed to use a (high-energy/low pressure) hybrid powder, in this case Norma URP. I threw all my favorite primers at it and got horrible velocity spreads and awful groups. Because I had some left, I used the WLRM primers, and, voila, very tight velocity spreads and consistent 1/4 MOA groups. You could downright 'feel' that that combo worked well - where the other primers ignited rough and inconsistent, with URP/WLRM it just made 'swoosh'. On the other hand, when I wanted to use URP for my .404 Jeffrey, I had to find out that neither primer, including the WLRM, could properly ignite the powder in that case, simply didn't work at all.

So, hot or not so hot primers are not the issue, you just have to try and measure velocity spreads - the tighter they are, the better powder and primer are matches in a particular case.



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