Wow! Love the CAD drawing.
Thanks
It is interesting for me to reflect upon my personality and my response to the earlier questions about FB etc...
One thing I despise on forums is when someone posts opinions and digs in their heels and acts like an expert when they are clearly not. I was a bit afraid that I looked like that kind of person when I asked my questions (and asserted that I had spoken with Rich) and then down comes the information that I was incorrect in my assumptions.
In academia, reputation is pretty much everything. I am fairly well-known in my particular area, and so I must be a bit sensitive to this issue
My response has perhaps had a bit of defensiveness to it. I could see how someone might say "that Britt guy doesn't know what he is talking about and Rich came down and set him in his place". I know that isn't what Rich intended. He and I have had a number of lengthy and pleasant conversations and shared data and he seems like a great guy. However, I felt an internal need to respond to set the story as correct as I could.
So, in summary, I have drawn scores of very detailed CAD drawings on specific chambers with specific bullets. This includes the various Sherman chamber dimensions as well. I did all of this BEFORE I posted my questions, since I always try to be informed. My specific interest lies in the relationship between chamber design and bullet selection and how they affect bearing engagement in the neck, intrusion in the powder column, COAL, and jump. Part of it is driven by my interest in gas guns (in addition to bolt guns) and the attendant problems that magazine lengths place on those cartridges. The same is true, although to a lesser extent, in bolt action repeaters. It is INCREDIBLY frustrating to deal with the terrible lack of standards around bottom metals and magazines. A simple question like "I want to feed a SAUM/WSM based cartridge in an M5 DBM using an AICS-pattern magazine in a Remington 700 clone long-action" should not be complicated. Unfortunately, it IS and there are literally dozens of 'informed' answers that range from "they don't work reliably" to "it is easy, just get a so-and-so magazine and bend the ears until it works." I literally spent 30 minutes talking with the original designer of the M5 Badger Detachable Magazine (he started Badger Ordnance) who worked with Accuracy International to come up with the AICS magazines for the M5 BDM. He flat out said that he doesn't recommend SAUM/WSM based cartridges in such a system.
By the way, the irony of the changing acronym from the original M5 BDM with AICS magazines to the current M5 DBM with AICS-pattern magazines should not be missed. The original design was a REAL Accuracy International magazine coupled with a REAL M5 Badger Detachable Magazine (BDM). The profusion of clones (some of them quite good) now requires us to say AICS-pattern magazine with an M5 Detachable Bottom Magazine (DBM).
That lack of standards, combined with sloppy definitions of critical ideas like 'touch', 'jump', 'jam', freebore, lead(e), throat, COAL, base to ogive, etc... just drive my academic sensibilities nuts
