Something I've wondered about.
After the U S Civil War Federal troops were allowed to buy the rifle or Musket they had carried in the service along with cartridge boxes and ammo at a reasonable price. I suspect that the difficulty in cleaning up and greasing for long storage of that many black powder arms made selling them off cheaper than taking them back to the arsenals.
I've also heard of Army officers and reserve officers purchasing their sidearms.
What I'm wondering is if any WW1 rifles were available for direct purchase from the government by demobilized troops on return to the U S?
I know that there was some sort of a prohibition against selling any U S martial arm in .30-06 caliber to civilians at some point in the 30's. This was one reason that Francis Bannerman developed his hybrid military styled .30-06 rifle, for sale to match shooters who wanted a military style rifle in .30, as well as for possible military contracts in South America.
Some sporting rifles were built on surplus Low Number actions, often subjected to a drawing and reheatreat process that may not have done anything to strengthen the action, and some drill rifles were built on pre production 1901 receivers.