I think two 25 round mag won't be too long and make a good 45rd mag.
Also, if it doesn't work two 32 rounders aren't damaged.
The Uzi drums are expensive.
I would say under $360 since you can buy a 100-round Beta drum here.
https://store.avguns.com/magazines-drums/drum-mags/beta-mag-uzi-9mm-100-round-drum-magazine/
I use the standard Winchester white box from Walmart, Federal Eagle, PMC, or any other name brand I can find at a decent price.
I don't use a buffer, just the standard recoil spring.
I also have a B&G bolt. I would just enjoy it as is.
Go back to an original spring to clear your issues.
It may be easier to and press your own 9mm ammo to
slow it down a bit. You could also get a suppressor for a
different feel. To me the suppressor smoothes out the
feel in full auto.
Long...
I have a registered UZI bolt and heard it can be cut down to fit in the mini UZI and still be used for the full size UZI.
I'm not interested in messing with a very well running registered bolt. (Not broken and no need to fix).
I heard the FA Mini UZIs run fast. I would also think the reduced...
In original form the UZI wins hands down. You need the Lage aftermarket accessories to place the Mac on the UZI level. As Battering Ram NIB mentioned you should also consider the Mac10/45. With the Mac10/45 you can shoot 45acp swap out your upper and place Lage Suomi 9mm upper on and shoot 9mm...
I couldn't get mine to work with different mags and/or different mag catch.
If you want to shoot 9mm in your Mac10/45, I suggest you get the Lage Suomi upper for your Mac10.