Whether or not peening - actually, staking - (or any other method, such a Loctite) is necessary depends on who you ask. Some, like me, would tell you it's not the least bit necessary as your search seems to have revealed.

However, others will assert that any and all steps must be take to prevent the pin from moving side-to-side. Even to the point of fabricating oversize link pins from sets of gauge pins available in 0.0001" increments for about $100, as shown on pages 6 & 7 in this catalog: http://www.deltronic.com/literature/...ide.pdf#page=3

To put it all into perspective, a look at the Army Ordnance blueprints for the barrel and link pin (available in our Tech Issues section, 14th link down from the top) shows the largest hole can be 0.155" diameter and the smallest pin can be 0.1545" diameter.

The decision is yours to make. But if you do decide to stake it, do it this way:



Regards