Gemmer trapdoor Hawken with 38/55 barrel

[Triggersmith]

I've been shooting a 45/70 405 black powder cartridge in my 1873 trapdoor Hawken.  It bangs my shoulder pretty bad.  My question is. can I safely shoot a 38/55 smokeless cartridge in that same receiver.  I can get an identical sized barrel in 38/55 as my 45/70 barrel and just have to change the extractor a bit.  I figure 38/55 will kick a lot less. And I will have 2 barrels for the gun.  Any opinions out there?
Much obliged
Triggersmith

[Delmonico]

With black powder loads it would be fine, myself I would be a bit afraid of any Nitro loads in an original trapdoor, not that it would blow one up if at black powder pressures, but because the pressure curve of the Nitro loads is sharper and would perhaps wear it faster.  At the same level of pressure the 38-55 has less case head thrust, something few think about, but in simple terms is had less area to push on the breech.  This is the reason TC Contenders in 45-70 are not recomended for some of the heavier 45-70 loads even though the develope less pressure than the 223 it is chambered in also.

[Sir Charles deMouton-Black]

I just shot my 12.7 X44 R Swedish rolling block. (SEE MY POST -TOR - Billy Dixon...) It is quite light, but a wide military style butt plate.  It jumped pretty good, but was bearable.  Have you tried to rig up a "boot" to fill in the hooked rifle butt?  That is what worked for my Gemmer-Pedersoli-Sharps. 

Another suggestion.  Do a new stock styled on the "officers model".

[Triggersmith]

I just made a boot that changes the crescent shape buttplate to a shotgun plate.  That might just make a difference.  I will post some photos later.  Thanks Delmonico and Charles.
Triggersmith

[Sir Charles deMouton-Black]

You, your shpoulder, and the rifle will be happier now!