Take a look at the radius in the two eared clips and the single eared ones
in wde_1978 #18 post.
Now take a look at the bend in the remaining clip in fearofpavement post #9, the last picture.
Nasty corner there huh! see that lump of displaced metal inside the bend?
FOP, If you don't mind, can you pop that clip and get a tight closeup of it?
Might want to shoot a frame down at it in the groove first too.
Also look at the other end of it and see if looks like any movement.
Is there any marking or scraping in the groove?
That tight corner where the cir-clip is *bent* vs having a nice curve, sort of tells the story to come, I'd wager.
Just for giggles, How close can you get the lens to the clip after removing it?
Be interesting to see how much the metal is pushed to the sides in the corner of the clip bend.
I'd throw the caliper or mic on it too.
As for removing the ears? Dont snap 'em off, use a cutting wheel in your twirly tool to nick 'em off.
Then dress the burr off so that you don't have it hang the clip up in the groove and not settle in to bottom of the groove.
It can also sit on the burr, depending on the direction , So the burr's gotta be removed.
IF you're concerned with removal later, just make a little notch in the side the clip groove before you install things and then you're good to go at removal time!
This piston looks like you could get the ring out with no problem though, as it has a cutout at the lower side already.
Don't forget to look at the clip after it's in place to see if it fits.
Make sure it has the same radius as the groove.
i.e. is sitting down in the groove , the same depth, all way around the hole.