Check ebay, they may have sone with A1 threadding. I would just buy the smaller bore A1 barrel backs though. That's what I did. The Angel barrels are actually very nice.....
ETEK 3LT, with 14" Ti boomstick and cure 3 + bolt F/S
Vanguard creed eyes, membrane, bolt pin, detents F/s[/color]
Old school angel poppets/cup seals, spring detents(not sure which models) F/S