RJ nails that one - re semi's - 10 rounds, 100, or 1,000 - no real way to guarantee the next round will fire! That said - enough crud getting into a revo just could make it difficult to operate and all but fail.
So many variables but for each R9 owner, he/she must just break in their gun - find the ammo that suits them and the gun best - and then maintain the pup lovingly. In the actually unlikely event of any problems - and remember we do not hear back about the majority of cases where all is just fine - then if really necessary the gun would have to go back for a check.
IIRC, statistically - Eric told me that returns were very small in number indeed. I had some early hiccups as I broke in and tried different ammo - but am now well happy and confident in the gun's ability.
A final point - irregardless of our carry platform - and never knowing when Murphy might strike - it is essential to practice the basics of failure drills. No gun is or should ever be regarded as 100% certain in function - 99.99% maybe - but nothing in this life is 100% certain, other than that we don't live forever!