Why would the pessures be sustantially higher in the actual 2" gun than the test gun?
I had a long chat with Tom Armbrust about this. Test guns are all at least 2.75" chambers and maybe 3" for 12 gauge guns. There is no 2" chambered test gun (but there is a guy that will make one for ~$900). Thus, the load is jumping at least 3/4" to the forcing cones and maybe more. Tom said a 2.5" shell will lose about 300# of pressure jumping just that 1/4" in a 2.75" chamber. He did not know what a 2" loss would be, but 1000 lbs would not be an unreasonable guess and much more is possible. This might be worse for fiber wads, which is what I want to test.
In another long chat with the tech at Precision (Bret?), he has no idea at all what the effect might be. None. It never even occurred to him. But safe to way, it is likely that the data will be biased low, and that is dangerous, esp. if you are right on the cusp of a working load threshold (i.e., 8k psi).
I would not use some of the loads that Drew posted for this reason.
