Colt Walker MAP rating

Question
Dear Mr. Gage:  I have a Colt Walker new series.  Reviews that I have seen long past indicated that Colt used modern metallurgy in the new series, which make them somewhat stronger and more reliable.  I would like to see data that have the MAP for this model.  A phone call to Colt was unfruitful.  Do you know of any source that might have these data?  Thanks

Answer
Hello Dick. Not much more information than you received years ago. The 1847 Colt Walker .44 was able to fire 60 grains of black powder which, when coupled with an antiquated metal process, could cause a cylinder rupture. The problem was solved with the 1848 Colt Dragoon .44 Coupled with a shorter cylinder of 50 grains of black powder and an advanced metallurgy, the problem of ruptures ceased. If you own a Colt Walker 'Signature Series', the problem of metallurgy has been taken care of. I hope this information helps and thank you for asking for me. Charles Gage

P.s. What does MAP stand for?