And Today's Lesson . . .
- Thread starter Boomer
- Start date
http://www.shootingsoftware.com/pressure.htm
I watched a guy use one for an afternoon and have corresponded with a few guys that use them religiously. Pretty neat stuff and should be very useful if you have the patience and background understanding to calibrate it and use the data.
I've often thought about buying one, but these days, a 180 from my 30-06 at 2750, a 155 from my 308 at 2950, and 250's from my 338 at 2700 seem to do fine without any more technology.
folks,
I'll say it again here. I don't worry about initial expansion on virgin brass, so Boomer, I would not have measured web expansion either, but I also do not work up loads in unfired brass. All my brass is fire-formed first, neck-sized if being used in the same rifle, or full size the once fired stuff. This is done with a minimum load-10%. Provides for all the expansion you need to get the brass where you want it to start.
Then I work up my load. Since I shoot from a cold barrel, I used to have lots of time between shots. Once I added measuring and recording the case expansion to the visual inspection of the case base, seems time goes by faster. Good idea about the shellholder going to the range with me. I will be adding them.
While in the dim recesses of my youth, I have only ever over-pressured one rifle. My ancient .303Br. An 1898 Lee Calvary Carbine that I pushed well over the limits until I was having case separations on NEW brass. As a new reloader, I was unaware of the pressure indicators of the primer, base, web, etc. All I knew was, load it and shoot it.
As the bolt started to stick, noise increased, etc, an elderly man at the range (actually a pit) came over and asked what it was I was shooting. I told him, he asked to look esp when I told him the cases were cracking. I got a gentle but VERY firm lecture on what I was doing and an invite to his reloading club. I was a member of that club for the 10 yrs I lived in that area. I learned so much from some very knowledgeable people who kept me from killing my self or wrecking a firearm. I no longer shoot that .303 looking for the fastest/hardest/knock it down load. As a matter of fact, I no longer do that in any of my rifles, but that rifle in particular, gets light loads, throwing a 180gn bullet just under 2100fps.
Boomer, I want to thank you for your post. It has reminded me that even the most experienced reloader can get into trouble. Hopefully, this will help me be more mindful when I am working up loads.
Ted
I'll say it again here. I don't worry about initial expansion on virgin brass, so Boomer, I would not have measured web expansion either, but I also do not work up loads in unfired brass. All my brass is fire-formed first, neck-sized if being used in the same rifle, or full size the once fired stuff. This is done with a minimum load-10%. Provides for all the expansion you need to get the brass where you want it to start.
Then I work up my load. Since I shoot from a cold barrel, I used to have lots of time between shots. Once I added measuring and recording the case expansion to the visual inspection of the case base, seems time goes by faster. Good idea about the shellholder going to the range with me. I will be adding them.
While in the dim recesses of my youth, I have only ever over-pressured one rifle. My ancient .303Br. An 1898 Lee Calvary Carbine that I pushed well over the limits until I was having case separations on NEW brass. As a new reloader, I was unaware of the pressure indicators of the primer, base, web, etc. All I knew was, load it and shoot it.
As the bolt started to stick, noise increased, etc, an elderly man at the range (actually a pit) came over and asked what it was I was shooting. I told him, he asked to look esp when I told him the cases were cracking. I got a gentle but VERY firm lecture on what I was doing and an invite to his reloading club. I was a member of that club for the 10 yrs I lived in that area. I learned so much from some very knowledgeable people who kept me from killing my self or wrecking a firearm. I no longer shoot that .303 looking for the fastest/hardest/knock it down load. As a matter of fact, I no longer do that in any of my rifles, but that rifle in particular, gets light loads, throwing a 180gn bullet just under 2100fps.
Boomer, I want to thank you for your post. It has reminded me that even the most experienced reloader can get into trouble. Hopefully, this will help me be more mindful when I am working up loads.
Ted
I used to have the Ohler 43 version.
You glue an fugly strain sensor to the barrel shank, connect the rifle with a special wire, calibrate the system with a precision barrel measurement (dia), and shoot it.
The barrel stretches under the pressure the gauge sends the signal and the brain interpolates the data....
Out comes the pressure.
You wont like what it tells you about your favorite load...That is a promise.
Perhaps its not so fugly after all?
- Location
- Somewhere on the Hudson Bay Coast
Whether you use a strain gauge or rely on pressure signs on the brass to judge the safe working limits, ultimately the choice of pressing the trigger on the next load increment comes down to you the shooter/handloader. If the strain gauge indicates 55,000 PSI is it prudent to add another grain of powder if you are working on the assumption that 60K is the safe upper limit? Do the pressure indicators of previous rounds support going forward, or is it time to stop? Perhaps the days of reading the brass for signs of pressure are past us. Armed as we are with chronographs and computer programs, perhaps those of us who find is necessary to define the safe limits of our equipment, have come to the time where the use of technology to define those limits is mandatory. If I can afford to purchase powder by the keg, bullets by the 1000, and Euro brass when I'm too lazy to uniform North American brass, spending $150 on QuickLoad doesn't seem so terribly outrageous compared to replacing a bolt, an action, or an eyeball!
Life was simpler when all I did was load hunting grade ammo, accepting whatever accuracy good loading practices and the available components would produce, and accepting the velocity predictions of the loading manuals at face value. But when accuracy becomes the overriding consideration, it also becomes necessary to find the safe limits of pressure to ensure that when making small changes to a load it always works towards lower pressure, instead of saying, "Damn, I wonder if I could pull in that flier if I went up just another half grain." From the top the only direction to move is down.
The lesson I got from this experience is that my method of determining maximum pressure is no longer viable and has to change. As time passes, there will be other new propellants I will try, and they too might exhibit different characteristics from what I have come to expect. So I will run "new to me" loads on QuickLoad to ensure I'm not outside the parameters of safety and I will have my caliper in my shooting bag to ensure that real world shooting agrees with the computer prediction.
Life was simpler when all I did was load hunting grade ammo, accepting whatever accuracy good loading practices and the available components would produce, and accepting the velocity predictions of the loading manuals at face value. But when accuracy becomes the overriding consideration, it also becomes necessary to find the safe limits of pressure to ensure that when making small changes to a load it always works towards lower pressure, instead of saying, "Damn, I wonder if I could pull in that flier if I went up just another half grain." From the top the only direction to move is down.
The lesson I got from this experience is that my method of determining maximum pressure is no longer viable and has to change. As time passes, there will be other new propellants I will try, and they too might exhibit different characteristics from what I have come to expect. So I will run "new to me" loads on QuickLoad to ensure I'm not outside the parameters of safety and I will have my caliper in my shooting bag to ensure that real world shooting agrees with the computer prediction.
Well, I am NEVER going to invest in the "technology is best" side of the house. I don't buy fancy Euro brass ( I pick up range brass when I can), I use a variety of brands for reloading but none of them are Dillon, Forster, or Redding (most are Lee), and I can accept what my rifle and my research is telling me.
Boomer, I do not think we need to have these marvels to keep us safe. As I said in my first post, checking the data for a lighter bullet, 48gns of that powder was max. I would not have prepared test rounds up to 50gns in full 1gn increments. You did, your choice, your incident. This has helped me to better remember the inherent dangers in what we do. Luckily, this only cost you a bolt.
My heavy load development and experimentation days are now behind me. I am happy with my current arsenal, load choices for each, and components. They deliver acceptable accuracy and performance under the conditions I choose them for.
That being said, I hope to be heading out to the range next weekend with some new experiments. Gonna see the difference between a 7.62x39mm loaded with a 165gn bullet (yeah, I know, it's a .308") and a .30-30 with the same bullet. Time to put the rumours to rest.
