Thanks for the response Bob. I guess I am getting a little 'anal' about this whole thing. I know there are standards for the chambers, headspace standards, and standards for the ammunition. I certainly hope that ALL of the manufacturers conform to the modern standards. You are certainly correct about picking and using one brand of brass. That of course is my plan. However, there are many reasons why a person could arrive at a destination and be forced to locally procure some factory ammunition. I can think of several that have already happened to me!! So my concern was that I would be able to purchase ANY available factory ammunition and use it safely should the need arise. I really don't think wanting factory ammunition to be within standard specification is too much to ask. Anyway, the published differences in the books gave me pause--a reason to stop and think. Like I mentioned though, I have NOT at this point verified with SAAMI or CIP what exactly the standards are. I need to do that.!!

I have chamber prints from a tooling manufacturer, but unfortunately my set does not include the early British cartridges. Maybe I will try to update them too. In any event the rim thickness was my real concern. A chamber cut for brass with a .040 rim thickness could have REALLY excessive headspace if you happened on a batch of factory ammunition with a rim thickness of .035--plus allowing for manufacturing tolerances..!!! Could be an accident waiting to happen.!!

The second thing about the chamber pressures was sort of a "just thinking..??" subject. If the rim diameters of the .470 and the .500 are indeed the same (as I tend to think they are...??), and the .500 is loaded to lower pressures, then the breech thrust could be significantly less. Perhaps a good reason to look at the .500 instead of the .470. Of course I realize that moving a heavier projectile down the barrel at the same velocity will result in more "shoulder thrust" too.!!

I know that these two are on the 'hefty' side as far as really useful choices--however, the plan is for Africa next year and hopefully several more times after that. I also go to Alaska and BC regularly, so they would work there for the big bears. There is also a hope for a trip to Aussie land for buff at some point. Who knows what **** lurks in the hearts of men?? I know, I know.!! It's the Shadow. The Shadow knows!!

Thanks for the kind words about the engraving...It's not master class, I know. I spent about two years part time in an engraving school back about twenty years ago. I worked as a hand engraver for a couple of years then started teaching engraving at a local college. I actually contacted a firm in Liege about fifteen years ago about moving there for a year to do an understudy. Couldn't afford it. You work on their line and products after passing some basic skills trials. They use you for all of the minor work until you prove yourself, eventually learning enough to work on their finished products. It is just like a regular job, only of course there is NO pay at all. Your 'learning' is the only pay you get. I just couldn't afford to live abroad for a year or more with no income.

Issues with the two potential donor guns: Well, there are several. I am going to post some pictures in the next day or so with comments and some questions. I am sure someone will have something to say...

Howard