After some research, Xplorer found out that stock priming handle rods are 4.3mm in diameter while the priming slot is 4.8mm.  This difference produces some slack (which is fine in a stock blaster) and will cause the bolt sled to slide unevenly on the shell, hence putting uneven stress on the parts which will eventually cause a critical failure, i.e. broken bolt sleds. We also found out that after hundreds of primes, the bolt between the handles will bend and it could reach a point where the bolt sled will not latch onto the catch plate.  Thus we produced the Xprime with the following advantages.

4.75mm solid steel priming bar

- takes up the slack and produce even priming

- will hold up better and longer than stock priming rods

knobs are fasten with a set screw

- can be quickly opened for blaster repair and storage

UPDATES: KNOBS WILL NO LONGER BE KNURLED

Knurled knobs on both sides
- for good grip

- ambidextrous

- lower profile for aesthetics