A group men who were childhood friends, lots of flashbacks to when they were boys including the locking away of a 'memory box', they all meet up as adults to open it. One of them gets shot as a child and when they open the box there is an old note from him saying 'To the best friends a guy could ever have.. '

For sum reason I think it may star kevin bacon.. also robert dinero,let meknow if this helps..

MacGyver (Eighties TV series)
"Blood Brothers"
IMDb synopsis:
MacGyver returns to his hometown to find himself haunted by the memories of a fatal shooting accident when he was a kid. While he is there, he helps two teenagers battle the local drug dealers.

"MacGyver" Blood Brothers (TV Episode 1988) - IMDb

You can read the complete plot summary here:
Blood Brothers - MacGyver Wiki
Excerpts:
Mac returns to his hometown in Mission City Minnesota to make good on a promise he made with his three best friends Jesse, Neil and Chuck to return 25 years later and dig up a time capsule they buried.. .
As Danny slips down the stairs, Mac is reminded of the accidental shooting of his friend Jesse. Mac had stopped Neil from shooting a bird after firing at some bottles, and in doing so had knocked the gun into the air, whereupon it had fallen to the ground and accidentally discharged, firing into Jesse's chest. Meanwhile, back in 1988, Danny's slip-and-fall causes the gun to discharge, shooting him in his lower stomach region. Mac calls out Jesse's name, but snaps out of his haze and gets Danny to a treatment room where he applies gauze to his wound.. .
Flashback to 1963, where the ambulance has arrived and begins to treat Jesse's injuries. The story continues to mimic itself between the two times, as Mac begins to perform CPR on Danny, while the paramedics work on Jesse in 1963. Sadly, a blanket has been pulled over Jesse's face, who has slipped away. Back in 1988, Danny however manages to hang on enough while being treated to garner a pulse, and he's quickly shipped off to the hospital.
Mac, Neil and Chuck return to their meeting spot, where they discuss how Danny will recover and Sean is now in rehabilitation. They unearth the time capsule, where Mac pulls out a giant rubber spider. Neil had put it as a prank on his 10th birthday cake, where his mother had beaten it (and the cake) to death thinking it was real. Mac tosses a baseball inside to Chuck, who had aspirations of playing for the Minnesota Twins. The third item pulled out is a non-lethal mousetrap Mac had made as a kid, consisting of a light strainer that would snap over the rodent,keeping it alive and able to be released elsewhere. Finally, in a somber moment, Mac pulls out an envelope, where they gather around and read the inscription on the back of a card-"The best pals a guy ever had". Mac pulls it out, and it's really the back of a picture of the four of them posing in hunter's caps, toy pistols in hands. Mac voices that they all miss him. Fade to black.

Here's a clip about the episode:
http://www.youtube.com/watch?v=biYyI8YjsDM

The one with De Niro and Bacon is Sleepers (1996)