Pressure
- Thread starter winston
- Start date
G
Guest
Guest
That depends on what you mean. If you mean, "How can I get a reading in psi of the pressure my loads generate in my rifle?" the answer is, "Not very easily." You can invest in a strain gauge setup and then epoxy the strain gauge on your barrel (over your chamber) and then shoot the loads to get a relative pressure reading, but if you want true pressure, you need controlled conditions, a reference load, and it will cost a ton of money.
If you mean, "How can I be sure my loads are not overpressure and that I don't leave undue amounts of performance on the table?" the answer gets a little easier. What you can do is follow known load data, watch for pressure signs, and work up carefully. Once you get to the target velocity or the max load, or a load that shows pressure (whichever of the three comes first!), you stop working up, obviously. Then, you start looking at accuracy loads, and adjust seating depth, and maximize your precision. Then, 50-60fps aren't as important.
If you mean, "Are my loads overpressure if they're doing X?" then the question becomes looking for pressure signs. Know that there is no free lunch. Pressure makes velocity, without fail. So if you're loading a book load, getting 200fps more velocity, and no pressure signs, you do not have a fast barrel. You just aren't seeing the pressure signs because of harder brass, a more forgiving chamber, or some such. If you're getting primer cratering or flattening, and sticky bolt lift, and erratic accuracy, you may have pressure problems and want to back off a couple or three or five grains and work back up.
Hope that's helpful.
If you mean, "How can I be sure my loads are not overpressure and that I don't leave undue amounts of performance on the table?" the answer gets a little easier. What you can do is follow known load data, watch for pressure signs, and work up carefully. Once you get to the target velocity or the max load, or a load that shows pressure (whichever of the three comes first!), you stop working up, obviously. Then, you start looking at accuracy loads, and adjust seating depth, and maximize your precision. Then, 50-60fps aren't as important.
If you mean, "Are my loads overpressure if they're doing X?" then the question becomes looking for pressure signs. Know that there is no free lunch. Pressure makes velocity, without fail. So if you're loading a book load, getting 200fps more velocity, and no pressure signs, you do not have a fast barrel. You just aren't seeing the pressure signs because of harder brass, a more forgiving chamber, or some such. If you're getting primer cratering or flattening, and sticky bolt lift, and erratic accuracy, you may have pressure problems and want to back off a couple or three or five grains and work back up.
Hope that's helpful.
DrMike
Ballistician
- Nov 8, 2006
- 38,189
- 8,282
dubyam nailed the answer for you.
- Oct 30, 2004
- 24,980
- 5,105
Also you can check Case head expansion.
Bruce Mc
Handloader
- Oct 26, 2005
- 1,456
- 1,110
And you can measure your primer pockets or just pay attention if they get loose when you're seating primers. This is also a sign of high pressure.
