Tag: ballistic data

Admittedly, it has been three weeks since I went to the range and got this data. On that day, the temperature was 87 degrees. It was the farewell to summer for sure because we are finally back to normal, Oregon weather. For the uninitiated, temperature is important when gathering range data because this is about measuring results of a chemical reaction.

The warmer the outdoor temperature, the more likely the reaction happens faster. This ultimately translates to velocity. This is what leads to the rabbit hole of reloading. It is possible to develop cold and warm weather loads. For today, I am going to ignore the fact that it was warm but I will keep the data point for some other day. I do have to say, my measurements were higher than I expected by quite a bit.

This is using a 158 grain jacketed hollow point by Speer and Alliant Power Pistol powder. The grid shows velocity by powder charge.

Now, that is some tight data. Everything did what it was supposed to do. I base that opinion on the standard deviation numbers. Surprisingly, published velocity is is only 1078 fps. My variations from this recipe include a Winchester Small Pistol Magnum primer instead of CCI 500. I also used a standard Speer jacketed hollow point instead of a Speer Gold Dot hollow point. This was also measured from a rifle with a 16″ barrel, not 10″. So, these are some variables that could possibly make a difference.

It could also be me or my equipment. I was organizing data over the last weekend and I noted in my reloading book that my electronic balance was reading 20% more than the mechanical balance. It is very possible that these are overcharged. I really need a third source to check my equipment. Nevertheless, I am much more pleased with this combination over the last one.

I will summarize last month’s findings here: same bullet, same primer, Universal powder. The published velocity for that load was 1100 fps. I used the same rifle. I would say that this one underperformed.

Before we declare a winner, velocity is not the end all measurement. There is also accuracy. The truth is, I haven’t even bothered to test this yet. My rifle is not sighted in and I haven’t even tried at this point. But, where I go from here is that I repeat this test on the rifle range and try to shoot groups. I can ignore velocity because I have enough data to tell me that the change is very small between starting and ending. This is the process of developing a custom load for your firearm.

What I can say from this experiment is that I have some ‘low velocity’ bullets that are not supposed to exceed 875 fps and it looks like the Power Pistol powder is not a good choice for that bullet. But, Universal probably is. The low velocity bullets are softer and exceeding the recommended velocity will cause the lead to accumulate inside the barrel.

Don’t forget that measuring velocity from a pistol should be quite a bit less than a rifle. So, it is possible to have loads that are too fast in a rifle but fine in a handgun. Aren’t you glad you just buy ammunition and live in bliss?

End Your Programming Routine: In this time of ammunition shortage which is even worse for reloading components, I have heard some advice. We probably won’t get our choice of what we want, so we just need to work with what is available. I have no hesitation substituting primer brands or bullets as long as you heed the fundamentals.