In factory built rifles there are not many small bore options. The one that comes to mind is Cabelas Blue Ridge, it's a very nicely made rifle with an excellent lock which takes a large 7/8" flint. All else being equal, a large lock with a big flint will be more reliable than a smaller lock with maybe a 5/8" flint. The Blue Ridge is made by Pedersoli and is available in both .32 and .36 calibers.