It has been almost a month since I have posted something. Lots of stuff has been going on, just not reported here.

Recently I started into a reloading and load development project. The subject of this project is the .30-30 cartridge, the first cartridge with smokeless powder made commercially available in the United States. It was the original round for the famous Winchester Model 1894 lever action rifle. I have a Winchester Model 94 which is essentially the same design as the original. I got it in 1976. I have put target sights on it and it is quite a nice shooting rifle.

So, what is the point. Well, I get highly variable muzzle velocities with several loadings. I did some experimenting a while ago and found that the particular powder I was using (IMR 4895) really needed a full case to give consistent velocities. If you filled it with powder, it was uncomfortable to shoot, so I used a comfortable amount and added rice to fill up the case. This worked. I was using a collection of brass from many different sources. That means they are not all dimensionally the same. They can be trimmed to a particular case length, but dimensions like wall thickness and shoulder position are not the same. Lots of variables here.

I managed to get an order of 250 rounds of Winchester unfired brass. Don't know if it was all the same lot, but it was the same factory about the same time. First step was to go through every one of them and measure case length. These measurements are to the thousandth of an inch, and I have a caliper which is capable. I found that they were 2.026 +/-.004 inches. From that I trimmed and selected 50 rounds that were 2.027 inches. FYI - a human hair is about .004 inches in diameter.

Bottom line, one needs to control all the dimensions to a thousandth of an inch. In the actual reloading of the cartridge, the bullet needs to be seated and crimped at a certain depth. That depth is controlled by adjustments of threaded parts of the reloading die.

This brings me to today's photo. If you know the pitch of the screw you can calculate how much a complete turn moves it in the die. The pitch of the threads was not quickly available from the manufacturers. So I got out a ruler and started trying to count threads. It was hard to hold the ruler steady and I lost track of counts every time. Photography to the rescue! I pulled out my IPhone and took a picture. When I printed it, I could easily count the threads. The pitch is 15 per inch. That calculates out to .067 inches per turn which is .0056 inches per hour (if you imagine a clock for the screw.) In the end, I made 50 cartridges with an overall length of 2.520 +/- .0005 inches. You really can achieve precision if you take your time and are careful. My friend John Cooper is an expert at this stuff.