Home Forums Reloading Big Game Rifles Lack of pressure signs on Lapua 308 brass?

Sorry for the delayed response, got pretty busy the last few days....

So I’ve run a bunch of different numbers with nosler and Lapaua brass (Nosler water capacity is 57.1, Lapua is 55.3). Used benchmark powder and 150 SST and 155 Scenar. No mater the combination I put together, my chronograph is on average 30-60fps faster than what quick load estimates. If I look at the chart and match up my velocities, the powder charge to get to those velocities according to QL is approx .5-1.0 grains higher than what I’m actually reloading.

Should I be adjusting the weighting factor or the burning rate factor?

I adjusted the weighting factor down to .45 (originally .50) and adjusted the following to fit my chronograph numbers very close:

Benchmark burn rate changed from .6860 to .7350
H4895 burn rate changed from .5571 to .5871

Are those changes normal or do they seem excessive?

My question, is your scale exact? Also, quickload is not an exact science. AS will tell you that. There are so many variables that you can't possibly expect quickload to be dead on every time, with every possible combination.

When you say scale you are referring to the scale I weight my powder correct? I feel like it is fairly accurate because I have verified it with another scale (both are somewhat inexpensive digital scales)

Main thing I’m looking for QL to do is predict chamber pressure because my Lapua brass is not showing me pressure signs. I don’t want to run the risk of thinking I’m below sammi pressure but I’m actually somewhere between 66k-69kpsi because my lapaua brass isn’t showing signs of pressure

Unless you are using a scale of high precision that resolves better than +-.01 or even better +- .001 grains, all scales have an error factor of +-.1 grains. This means that 33% will be plus a tenth, 33% will be dead on and 33% will be minus a tenth if all things are linear.