What can you tell me about this upper?

alanint · 10-09-2013, 01:30 AM

You really should not be swapping a .30 cal. lower with a 9mm upper, unless you change recoil springs as well. The 9mm is more powerful than the 30 cal. and the weaker .30 cal. spring will cause malfunctions and possible damage to your pistol.

rhuff · 10-09-2013, 04:47 PM

I am sorry, but I have to respectfully disagree with Alanint. In my "convertible" Alphabet Luger, I installed a new std. 9mm recoil/main spring, and with my 30 Luger ammo loaded to factory spec, it will function the same as the 9mm ammo. I also have a less stiff main/recoil spring, but I opted to try and error on the safe side.....and I believe that I was successful. If one were loading either or both rounds "soft", then you would most likely need to start changing some springs around.

10-09-2013, 01:30 AM	#1
alanint User Join Date: Mar 2008 Location: Marco Island, Florida Posts: 4,867 Thanks: 1,685 Thanked 1,917 Times in 1,193 Posts	You really should not be swapping a .30 cal. lower with a 9mm upper, unless you change recoil springs as well. The 9mm is more powerful than the 30 cal. and the weaker .30 cal. spring will cause malfunctions and possible damage to your pistol.

10-09-2013, 04:47 PM	#2
rhuff Patron LugerForum Patron Join Date: Mar 2011 Location: Az. Posts: 2,314 Thanks: 2,746 Thanked 998 Times in 733 Posts	I am sorry, but I have to respectfully disagree with Alanint. In my "convertible" Alphabet Luger, I installed a new std. 9mm recoil/main spring, and with my 30 Luger ammo loaded to factory spec, it will function the same as the 9mm ammo. I also have a less stiff main/recoil spring, but I opted to try and error on the safe side.....and I believe that I was successful. If one were loading either or both rounds "soft", then you would most likely need to start changing some springs around.