Not lead shot but .45 sluggs, put into the blade bolt. Lanny

The rotor heads were usualy balanced from the factory and to rebalance when changing blades only took adding or removing one or two 45 slugs.
The pins came with the rotor head and stayed with the head for it's service life.

Could pull the end cap

Jardo is correct on both counts,,,,however, you could balance by pulling the end cap. There were 5 studs (may have been 4) with 1/4 ounce flat shim weights caped with 7/16th lock nuts. I don't recall anyone ever having to do it though since the slugs always worked. Only reason I knew we could do it was I lost an end cap with Munford on an extract, talk a bout a beat....;)

We never touched the shims either, we still used .45 slugs, till the 9mm came in and had to go from there in the 90's, cause .45's were getting scarce. You'd think we had plenty, but Crew Chiefs horde stuff in their helmet bags, and as they left the .45 slugs did too.

Don't remember the Main Rotor Blade Pins staying with the blades, but with the Rotor head.

Track and Balance as well as Vibrexing was a HooT! Ya got alot of flt time on them hops, in the left seat of a Huey or in the front seat of a Cobra.