Starting back in 1968 I have serviced several Auto 5's that were jamming with failures to eject... the rings were set correctly, the tube was dry. Simply greasing the tube made these guns function as they should. I have never seen lubrication cause any damage.
I agree with you guntech, lubrication will never cause damage, I never said that it would.
It will in most cases when dealing with an unmaintained firearm improve function, better to
have some lubrication than nothing at all since a dry friction system will often over brake and cause ejection failures and premature wear.
Where grease will rear it's ugly head is when low temperatures are encountered, the grease will slow down the
operation to the point of failures to eject, this is compounded by todays high velocity loads.
Grease does funny things when the weather gets cold and we hunt cold weather.
Grease is simply not optimum lubrication for this application, It is worse today with rapid pressure spikes and very short durations
they lack the momentum of the older/slower lead loads and the very effective browning system overpowers the load= ejection problems.
Browning has never recommended grease at least I have never seen it in any of my manuals, if you have information to the contrary
please state the source, I would like to know where you get your info. from.
The Browning Auto 5 is a marvel in engineering utterly reliable but pushed to the limit with very light high velocity loads,
if you do things right it will be very reliable. Don't use grease in the braking system especially in the 3" guns with light loads.
Hope this sheds some light.
BB