KWG,
In one of my first posts I alluded to a chronograph even a cheap pro chrono or chrony would suffice. The reason for this is that I go by the old rule velocity = pressure. You can try looking at primers or brass all you want, but it is still one of the most inaccurate ways to judge pressure, which has been proven many times over the years.
Next you don’t have to use new brass, range brass will work just fine as long as you take the time to make them as even and uniform as possible. Weigh, deburr, uniform the pockets or whatever you desire. Uniformity is the key. For your test 10 cases should be sufficient.
Take the uniform cases without flash holes modified to the range and document the velocities and any other pertinent data that load gives. This is your control group or baseline. If you want organize each case to corresponding chrono order so you know which case did what.
Now go back home take these exact same cases, one at a time to maintain proper order, drill the flasholes to your first step. Repeat range day.
Now repeat this for all steps of drilling, when all is said and done you will have data that corresponds to each change in each case. Then you can compare it.
I will not argue that deburring and uniformity of flash holes is a wasted effort because it isn’t. I will say that there comes a point in time to decide if all that work is justified by the results. For general purposes you will find that your rifle can’t really take advantage of it. I.E. accuracy increase smaller than the amount of work. I did an awful lot of thing when shooting BR whether it actually helped is debatable, but it made me feel better. For the typical varmint gun or hunting rifle it just isn’t necessary.
Conclusion is that you might be better off changing primer brand than flash hole size as I have seen large changes in velocity/accuracy by doing this. Also save your components until you can afford a chronograph. Doesn’t have to be a magneto speed, labradar or an Oehler.
I agree Swifty. You provided good information. I'm starting to get that pressure = velocity thing. Yes, I want a chrono but it seems like something else always comes up that takes priority. I see the traditional style chrono's are getting fairly cheap. But, that Labradar looks handy and easy to use with a short set up time.
You are right about "the work justifying the results". When I was playing around with the various size of primer holes I wasn't getting the results I was hoping for after sorting brass, drilling the holes, keeping them together and getting back to the range. But, that masters Thesis as submitted by NVhunter and written by Nicolaas Martin Schrier; well, it had my curiosity up. It might of paid off for Mr. Schrier but I wasn't seeing it.
I have used several different primers. Just like everyone else when the time is right I pick up a brick or 2. I was getting Federal match primers after I wasn't getting the results I wanted with CCI 400's or 450's (for .223) but the Federal Match primers have been pretty non existent the last 11 months. This guy on YouTube got me looking at the Federal match primers. Bob's reloading:
https://youtu.be/N7KVBWChnyY https://youtu.be/GaYKzLHWYvUHas anyone had any contact or use with this brand of primer hole uniforming device? Has anyone found any improvement in accuracy ??
https://kmshooting.com/product/premium-carbide-flash-hole-uniformer-builder/Anyway, it was interesting trying out the various primer hole dimensions but the lessons seems to be that it doesn't always matter what size the primer holes are as long as they are the same size. Just go back to the last page and see the picture that Mule Deer posted of the primer holes in the Grendel brass. Two different primer holes sizes but whey they were shot with their companion brass the accuracy was practically identical.
Enough is enough. Lessons learned.
kwg
