Colt Walker lever holder / clamp

The Walker had an inadequate loading lever catch that often allowed the loading lever to drop during recoil, preventing fast follow-up shots (see [Wikipedia](https://en.wikipedia.org/wiki/Colt_Walker#Problems)). This also applies to currently manufactured Colt Walker replicas. Period-correct fixes for this often included placing a rawhide loop around both the barrel and loading lever, to prevent the loading lever from dropping under recoil and locking the action.

Here is a period-incorrect at