Try reading the third paragraph. Shanklin is clearly describing the search of the limo which was conducted in Washington the night of the JFKA. The memo says they found the bullet that killed JFK which was the fragmented bullet. Landis claimed he found a whole bullet in the rear seat. He claimed he put it in his pocket and then placed it in a blanket by JFK's foot. That would have been an incredibly stupid thing to do for a 28 year old agent who still had all his marbles. Landis was 88 when he told that story and clearly his front porch light was flickering. I imagine his cognitive decline has continued over the past 3 years.
You're forgetting about the JFK Limo being flown back to DC aboard the C130. If you believe the SS did Not get inside that car during the long flight back to DC, your gullible beyond belief. I believe this is when this bullet was found.
Strange, that pieces of JFK's skull would be found and immediately marched into the autopsy room for fitting into the holes in his head. Yet, there was No Mention of this bullet while Humes et al were X-Raying JFK's body from head to toe amidst the search for a missing bullet. No, not strange at all. Humes was snooker'd.