Perry;
The difference in the High & Low Walls can be seen at a glance. Just look at the top line of the receiver & breech block. On the low wall, the top of the receiver slopes down at the end of the barrel threads, at the front of the breech block. The top of the breech block also has a slope to it. They have a very pleasing appearance to them but the breech block remains unsupported up behind the cartridge, depending on the strength of the block itself to contain the load.
On the High Wall, both the top line of the receiver & the breech block extend straight back beyond the block, This leaves a shoulder in the receiver wall all the way up behind the chamber to support the block, thus greatly increasing its strength. The high wall was used for large & hi-intensity cartridges while the low wall was restricted to lower power rounds. The first gun I ever fired in my life was an 1887 (model 1885) low-wall chambered in .22 Long.
