1851 Navy replica conversion question

[Markbo]

I have an brass framed Italian 1851 Navy .44 that I was thinking about getting a conversion cyloinder for. The only source I can find states not to be used with brass framed models.

Is this due to some inherent weakness in the brass frame? If kept to realistic (read sub 900fps) loads, would this be safe? I bought this as a wall hanger and am not interested in shooting round ball and black powder.

[tas6691]

The brass frame guns are weaker than steel. They wont take the presure of smokeless powder in the conversion cylinders. Frame stretch, not good.