Compression copper cable lugs, such as those made by Pioneer Power International, are intended for one-time use only. When you crimp the lug, its barrel gets permanently shaped to form a gas-tight, low-resistance connection with the conductor. This process guarantees excellent electrical and mechanical contact, but it also means the lug can't revert to its original form. Trying to reu... https://www.pioneerpowers.com/copper-cable-lugs.php