Internal or external snap rings? I've always had good luck using the OD of the shaft and relying on the snap ring to fill the groove. We used to use Tru-Arc internal snap rings for piston pin locks, bit after losing a couple at high speed, we switched to Spiro-Lock rings that don't respond to high piston speeds and come adrift.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!