It's pretty much certain that cast iron receivers weren't issued for anything other than drill purpose. As a matter of fact, a late dear friend and I tried to duplicate PO Ackley's test with a late last ditch Arisaka model 99 in 7.7 calibre as well as an earlier type 38 in 6.5 calibre, they were about $5 apiece at the time and were a real pain to customise, there weren't any aftermarket add ons available either. The type 38 had been ridden hard and put away wet, the type 99 didn't have a bayonet lug and only had a fixed rear sight, the receiver was still in the rough though there was still a mum on the top, the rails, bolt lugs and face were machined rather well and the bolt handle was welded on, chamber and bore were as new, the stock was finished to the lowest standard I've seen on any military issue rifle (doubtful it ever saw service). These rifles were picked out of barrels at Kesselrings, in the good old days when even Liberals were shooters. Anyway to make a long story short, after reaming the chambers out with a 30-06 reamer and loading some cartridges up with all the2400 powder they could hold and still seat a bullet.
we couldn't blow up either receiver. The type 38 receiver used in that test is still in service today in 6mm Remington and doing fine work on a farm in Saskatchewan. I've heard all the old stories about Arisakas, and just like you, believed them. But when we learned from a few friends that were in Korea dureing the 50's about the Arisakas (type 99) that had been rechambered by the US gov't to arm Korean troops, we knew there had to be something amiss with the myths that were in vogue at that time. I now wish that I had picked up several of those at that time, cheaper than Lee Enfields and lots of bayonets, slings etc. We didn't think it woul ever end. Hindsight is 20-20. I can understand where you're comeing from, when you talk about the cast iron receivers, they certainly did look like cast iron. bearhunter