Quick Load
- Thread starter solocam
- Start date
When starting a new load development you need to start low and work your way up.
He means you have to find your max load on your own because you can't trust published figures to be correct in your rifle. Don't start at any "max" load. Start near the min, and load up about five cartridges in even increments up to the max listed. Shoot them sequentially and carefully observe for any signs of pressure. If you find it before you reach "max", then you have found YOUR max. If you don't, then your max may be higher than what was published, and you find it by going higher in the same increments until you see pressure signs.
Load Data from manufacturers > untuned QL data
QL is extremely useful for ballparking new load combos, seeing what changes affect pressure/velocity, but out of the box it's not going to be accurate enough to match ground truth. I often end up having to tweak H2O volume on the case, and burn rate / specific heat on the powder to tune QL to match the ground truth through testing. Once that's done it can make pretty accurate predictions and save you a LOT of time and money. But if you're looking at load data saying 29.5gr is max, but QL tells you it's not - trust the load data.
QL is extremely useful for ballparking new load combos, seeing what changes affect pressure/velocity, but out of the box it's not going to be accurate enough to match ground truth. I often end up having to tweak H2O volume on the case, and burn rate / specific heat on the powder to tune QL to match the ground truth through testing. Once that's done it can make pretty accurate predictions and save you a LOT of time and money. But if you're looking at load data saying 29.5gr is max, but QL tells you it's not - trust the load data.
First you need to make sure you’re using the same components. That means bullet, case, powder, primer, as well as loading to the same cartridge overall length.
Then you need to determine case volume, but especially important, for your chamber. That means the case fired out of your chamber because chambers vary in size from one manufacturer to the next.
The difference in case volume affects the maximum charge you’ll be able to use. A heavy case fired out of a small chamber will have the least case volume while a light case fired out of a big chamber will have the most. The more case volume the lower the pressure given a particular powder charge.
Hmmmm???
You really shouldn't try to start off with anyone's max charge weight. IMHO, it's best to use the lower of the high max numbers as a general guide and start testing well below that number. As mentioned, start with lower charges and work your way up and the best way to do that is run a pressure test. "Pressure test" where you load cartridges in increments of powder charge (just one cartridge each) like in .3 or .5 grs apart and go just beyond max load. As you fire each cartridge from low to high, you stop when you first get some pressure signs. That'll give you a good idea of the max charge for that powder in your gun. And if you're chronoing the velocities, you can tune the QL powder data to match what you got and be able to use QL more effectively for that lot of powder.
Like @Dogtown said. I shoot a few charge weights so I can true QL. I can trust a trued profile. Then we shoot across the barrel time somewhere around 1 to 2 grains off max. I have had very good success finding the load the gun likes doing that. If I have to do this in a single range trip, then I pack the portable load equipment and do it all at the range.
You need to understand the difference between the two sources of data. The Hornady data is based on actual test firing of the specified components in an instrumented and especially designed barrel designed to indicate the maximum pressure that would be obtained in the smallest chamber meeting the SAAMI specification for that cartridge and components. Quick Load and Gordon's Reloading Tool are simulation programs that are intended to model (predict) what the pressures and velocities are when varying components and dimensions. One of the biggest differences between the QL and test is what the actual powder properties are. Another major difference is the actual chamber volume difference due to real world chambers and case capacities. All simulation programs require truing to provide accurate predictions. In this case that usually requires truing the actual velocity to the powder model/quantity.
While it is easy to say that the Hodgdon data is conservative and lawyered up it is conservative by design. But it is also based on a specific testing protocol and in barrels and chambers that are highly controlled. Real world chamber are different and vary in condition and in the case of specific reamers and bullet combinations can yield different results. Hence the warning to start low and work up.
