Ammo is easily available and no more expensive than any other ammo of similar type. I own both the 36 and the 49 (from the looks both refurbushed and stored by the Frenchbefore being surplused) and I ordered ammo from Graf and Sons. Availability is on again off again like all ammo right not.
The rifles are extremely accurate and very functional but lack a bit in looks. Dies for reloading are available from several sources such as Lee and bullets are standard 308. It is a simple reload. As stated stay away from any converted rifle. I understand that there were some French made rifles in 7.62 NATO but I would never buy one without being absolutely sure that it was original.
It would be a great rifle for your purpose.