1911 10mm conversion

[Sailormilan2]

I had a spare 6" 10mm upper laying around not being used. So, I talked my youngest son into putting it on his Springfield Military 1911 45 acp.
First step was finding an ejector that would work, if possible, without modifying one of the slides. All calibers, other than the 45 acp Govt model, use a different sized ejector. Slides for other calibers should not work with the 45 acp Govt ejector, and vice versa. I managed to find one in my spares box that seems to work with both. Possibly out of spec?
Then cut and reshaped the frame tangs to take a beaver tai grip safety. Rock Island ambidextrous safety had already been installed, since he is left handed. After market round hammer had to be replaced with another narrowed aftermarket round hammer. Since the original one, not narrowed, kept getting jammed in the slide. Mainspring was upped to 25#, and I may end up going with a 28#. When it was previously mounted on one of my RIA frames, it was still hurling brass 10+ feet away, so upping the Mainspring to 28# may be necessary. Frame, original slide, and minor parts were then bead blasted and repacked very black.
So, now we have to test fire it and make sure it is sighted in. It still retains the ability to go back to the original 45 acp slide.

https://imgur.com/1e3oXqU

[eaglemike]

Which spring are you calling the main spring? Just asking for clarity, since you mention it's related to how far the brass flies. Are you referring to the recoil spring? I'm thinking a 25lb mainspring is going to make the trigger pull pretty firm. The mainspring has a plunger on top of it, which pushes on the hammer strut. The mainspring and recoil spring do affect how easily the slide travels to the rear, but the recoil spring does most of the work controlling the slide. There's other little stuff too, like the angle on the bottom on the firing pin stop plate that can be altered.
Good job on getting another upper assembly to work. Seems like the RIA stuff can be swapped out without a lot of agony. I played with stuff from various other suppliers in the past and had to straighten the cuts in the slides for frame rails, etc.

[Sailormilan2]

[Oldmandan]

I think it looks a little weird with that short ball end mill cut.

The link below, shows what it looks like if taken all the way back to the dust cover

https://danwessonfirearms.com/product/bruin/

Also, I think I read somewhere that 10mm in 1911 needs a ramped barrel due to extra chamber support needed

[ar15barrels]

I think I read somewhere that 10mm in 1911 needs a ramped barrel due to extra chamber support needed

Any cartridge that's much over 25,000psi should use a ramped barrel in the 1911 platform as the original design with the ramp in the frame allows a decent amount of the case forward of the extractor groove to be unsupported.

[eaglemike]

Understand. I think Wolff make springs for extended length slides, might be useful. I'd built a few .45 supers years ago running 22lb recoil springs, no issues, also had ramped bull barrels. Hope it all works well!