EFK 357 Sig Barrel Conversion Problem

[gunprofit]

I received my EFK 357 Sig barrel conversion for my glock 35. I fits and the action works when it is unloaded. When I load factory ammo, the barrel will not cam up into battery. It is 1/8" or more from closing. Of course, it will not fire the cartridge, nor would I want to. When I remove the barrel and insert a factory cartridge, the base of the cartridge protrudes above the back hood of the barrel. This is the reason it won't go into battery. I suspect that the chamber is short since this caliber headspaces on the case mouth. Any ideas? I made the purchase from Topglock and they are closed until Monday.