Unfortunately I don't have a 10XX at the moment, but I would take a .357 sig barrel for a 4006 when you get to round two.
#1. Drop-in means more clearance to fit all the guns, no guarantee of the accuracy but it will be no worse than the accuracy equivalent to the factory barrel.
#2. Semi drop-in, the spherical diameter on the muzzle end would be left oversize by .002" - .003" to be polished in by you,
just need to spin it in a "devise" and polished to fit with as little as 600 grit silicon carbide sandpaper or as little as a "Scotch-Brite" pad.
If you wish, the breech face locking lug to the barrel/slide locking lug length can be left over a little bit at this point and you can "file" it in.
I would need to know that request when the order is received.
#3. You can send in your complete slide and barrel assembly (barrel and recoil guide rod and recoil spring)
and your barrel will be match fitted with aerospace gauges that measure as small as .0001",
the breach face locking lug, barrel/slide locking lugs and muzzle spherical end fit to your barrel bushing all in your slide, as I did with my 9x23 Bar-Sto.
#4. You can send in your gun, it includes #3 (above) and the bottom lugs will be fit to the frame and slide release lever locking pin for a total match lock-up.
If the slide overlaps the frame in either direction at the rear, I can match it better at this point (with the new barrel).
If your slide protrudes over the frame, with your factory barrel, I can/will correct that also at this time.
(I had correct this with my 9x23 Bar-Sto)
If the frame protrudes out from under the slide, there is nothing I can adjust to repair that.
This also includes range test firing with std. "over the counter factory ammo" to determine a recommended Wolff spring.
I purchased the full range of springs for both length barrels.
(Does not include 9 X 25 Dillon unless you send me 10 - 15 rounds)
The manufacturing facility that I am working with is a Class 07 FFL manufacturer.
Best regards,
BM1