My Alex Henry 450 NE had a tight chamber and a Lawson 450 BPE with the same issue. Both got
sent to JJ in Oklahoma to be reamed for modern brass. Simple around $200.00 each. My two Holland
450 BPE and a Rigby chamber modern brass. I've used 450 dies from CH4D, Hornady, and RCBS. RCBS won't make custom dies, and CH4D is one year waiting period. JJ has a fast turn around time.