Thanks for the clarification, Miller. I puzzled over the statement as written, especially coming from you, but without your supplied reference it didn't make sense and now it does.
Regarding the rest of your last post, I agree completely with each of your points regarding the best test practices, and lack of conclusions that can be drawn from the practices used. However, I don't think that the answers that we are trying to divine from the data are necessarily the ones that the manufacturer was after. Their primary interest is in showing that 1)There is no significant degradation of patterns with the use of their subgauge adaptors, and 2)There is no significant reduction in velocity with use of same. When they tested it themselves they got data that showed actual INCREASES in velocity around the order of 100 fps. That's when they decided to have someone else run the tests. I suspect the decision to measure pressure was of secondary importance. Nowhere has the manufacturer ever mentioned use of their product for older guns with lower pressure requirements, so I don't see that as being the purpose of the tests (but of course we would all love to know). Bell mentioned in the letter the problematic nature of getting the strain gauge in the same location for each barrel, but I don't fault him for not finding a solution if that was not in the client's specified interests, but it is disappointing for us. I agree completely with your deduction that the reason the 12/28 AA combo showed higher pressure than the 16/28 AA combo is for the reason you state - it was measured closer to the breech, and a crappy way to determine what we are discussing here. But Bell did not state any conclusions that there was an inherent pressure increase related to the bore size. He merely stated his methods, their problematic circumstances, and reported the raw data. This was sufficient for the client's purposes, but inadequate for ours, and we are left to draw our own conclusions. He satisfied the client's curiosity about whether or not the slight, and unexpected increases in muzzle velocity were real or the result of a fault in the manufacturer's own tests, and that was all they wanted.
What we don't know is if any other data points were constructed. My opinion, based on a dim recollection of a conversation with him over 2 years ago, is that almost certainly there were, and likely some of the very ones we'd like to know. If so, whether or not Sherman reported them to the client, or the client edited his report is the next logical question. In any case, we do not know for sure. Regardless, neither Sherman nor the manufacturer have stated any conclusions that pressure is either routinely higher or lower when using subgauge adaptors. Pressure has been treated more or less as a sideshow to the importance of velocities and patterns, and no conclusions about it are stated.
You stated that you would expect it to be highest in the 28, next in the 16, and lowest in the 12, and that if we are intellectually honest that this was not proven otherwise. In response I would state that it would also be expected that the velocities would also decrease, however slightly, in that same order, but the tests show otherwise - in fact they increased in some cases. That doesn't disprove your expectation, nor do I claim that you aren't precisely correct. However, if we are being intellectually honest, it would be very difficult for velocities to stay the same or increase if there was any SIGNIFICANT decrease in pressures, given that the load didn't change. All that Sherman stated to me was that there was no SIGNIFICANT decrease in pressures with the adaptors that would warrant any claim for their use as a safe way to use a subgauge load that develops pressure (in it's nominal gauge) that you would not want to put through the parent barrel with its own nominal gauge load of the same pressure. I think there IS enough data here to draw that conclusion (only). Anything beyond that is certainly Guernsey vs. Hampshire.
Last edited by vh20; 10/13/09 10:20 PM.
