The company is one of the most helpful and knowledgeable (obviously!) on the Rap4 468. I needed the older two piece pin the UK were originally unable to help but speaking to the US... view moregot it sorted. The pin arrived very quickly shipping cost well worth it as I am still waiting for the UK one to arrive.
Picture shows the ongoing build to make it into a working .68 M16A3 rifle with full solid type stock fitted. I am just waiting to sort a longer barrel and a birdcage flash hider.