Romano Spencer case length, Part 2

[dm3280]

I received the cerrosafe from Brownells today and just made a cast of the chamber in my Romano Spencer.  Now what to do with the info.  I am not very knowledgeable on this sort of thing so I ask for anyones help.

Here are the measurements as far as length only.  Once I removed the cast I measured it from where the rim starts to where the chamber slopes into the rifling and got a measurement of 1.170.  This is what Larry Romano told me his reamer was.  Add the case rim of .063 and I come up with a cartridge length of 1.233 max.  I am using Dixie 50-70 cases and trimming them down.  Am I calculating this right or do I need to leave some room for case expansion?

Thanks for any help

[Fox Creek Kid]

If you were shooting 1,000 yd. benchrest then the case length would be critical. The 56-50 cases will never stretch (per my experiences) after repeated firings as there is simply not enough pressure with real BP to stretch these for a LONG time, i.e., many firings.  I don't own a Romano but rather an Armisport, however the principles of physics are the same in any gun. What you don't want is a case too long as that will affect accuracy and pressure. Trim your cases until they just chamber and then trim another 0.003 more to allow for variations in rim thicknesses. CAVEAT: case length will grow longer after resizing. 

[Appalachian Ed]

We've been swapping email. For anyone else wondering,  Case length is 1.165, overall is 1.585.

-Ed