It take about 5 minutes to switch back to your original setup to shoot the 45acp. I would go that route. 5 minutes more to switch back to the 460.
I do not know the XDm that well. In a 1911, there are some simple tricks to slow the slide velocity down and hold the round in battery longer. If your are getting 25' ejection, you are tearing your gun up. Simple as that. I would call Clark Custom.
How are your fired cases looking?
One more thing, quit shooting your chronograph. Ha! Ha!
Agreed. I have some heavier springs on the way to slow the slide. I have heard and read both ways on this, some are saying the stock spring is fine, others are upgrading. I will be upgrading.
My cases are looking fine. Of course you really cannot see pressure marks on straight cased brass very well until it is way too late. I was only hitting 1157 on the first batch of hand loads, so I am doubtful that it is overpressured.
I'm not supposed to shoot the Chrono? Maybe that is where I am going wrong! Actually, the sun was out and bright, so the diffusers were not doing their job too effectively. I got some readings on the first batch and then errors after that.
Johnny Rowland of 460Rowland.com came up with the idea for the cartridge, but the does things with it that Clark will not do as far as the pistols he sells barrels for and what shoots in what, and I personally think I'd take Clark's advice. This is a powerful cartridge, deserves respect and safe practices. I would listen to Clark - and others with experience with the round - and keep .45ACP ammo out of 460 Rowland chambers. Like Gibby said, you can switch back and forth between barrels - or just have two 1911's (my choice!).
I did look at Clark. He is an advocate for 1911's only. There is definitely great information there, but not particularly applicable to poly frames. There is much to be said for a steel frame cannon. I don't own a 1911 yet, but am certain that there is one in my near future.
