Nexus Firearms Enhanced Bolt Complete (CZ Scorpion EVO 3 / 3+)

The Nexus Firearms Enhanced Bolt is the safety upgrade for the CZ Scorpion platform. The factory bolt is forged from soft material around 43 HRC, and on a straight-blowback Scorpion the hammer rides over the bolt during reset and peens the metal around the striker block hole. Over enough rounds, a burr forms that holds the striker block depressed, defeating the in-battery safety. The platform has a documented history of out-of-battery detonations from this exact failure mode, and the wear rate accelerates with fast aftermarket triggers and binary triggers that outrun the factory bolt timing.

Nexus's Enhanced Bolt replaces the factory unit with a D2 tool steel body heat-treated to a minimum of 58 HRC, finished in Nickel Boron coating that adds approximately 70 HRC of surface hardness. The internals are 17-4 stainless heat-treated. Together this is roughly 35% harder than the factory bolt at the surface that takes the hammer peen, which is the difference between an in-battery safety that lasts hundreds of thousands of rounds and one that develops a wear burr over a normal training schedule.

This is the right upgrade for any Scorpion owner running aftermarket triggers, binary triggers, or running high round counts. It is compatible with both the original EVO 3 family and the new Scorpion 3+ Micro. Nexus also sells a bolt-only variant at $249 for shooters supplying their own internals, but the complete kit at $399 is the right purchase for most owners. Pair with the Nexus Evo Gen 2 receiver ($350) for the full delayed-blowback conversion that addresses the underlying timing problem rather than just hardening the bolt against it.