Greetings Jim Bob,
Do not be concerned about shooting your rifle with one barrel key. I shoot mine with one key on a regular basis. Many years ago, an extremely knownledgeable ML shooter told me that these rifles woul shot more accurately with one key. I find this to be true.
I build my own rifles and have a perference for replicating original Hawken rifles. These rifles have two barrel keys. On my rifles, there is the appearance of two keys, but in reality only the front key holds the barrel in place in the forearm. The rear key is for looks only and does not slide through an underlug. No rear underlug is even fitted to the barrel.
As a matter of fact, I have been guilty of at the last minute of fitting a new barrel to an existing rifle, not having time to install an underlug, and using black ruber electrian tape to hold barrel and forearm together. I have a TMLRA state record (50 - 4X at 50 yards) that was shot with a taped on barrel.
Several years back, I put an old, but unfired, Douglas barrel on a friends T-C Renegade. For testing purposes, we used my magician tape (available at thousands of outlets) to hold the barrel to the forearm, The rifle shot so good, it was two years before he would let me have it back to install the barrel wedge. He was sure it would
never shoot as good. It did.
My old Santa Fe Hawken rifle has been the base for barrel replacemennt and testing of numerous barrels. Those barrels have all been taped to the forearm. No problems have ever been encountered because of this.
Anyway, do not worry about it, and have a good time shooting. What is that old saying, "Let not your heart be troubled".
Best regards,
John L. Hinnant
If you are not an NRA Member, why not? I am carrying you load.