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8/14/2026 3:59:16 PM EDT
Seen a lot of folks ask if the Hydra Greasgun magwell is compatible with DI45 and 45 RDB, so I took the time to find out. I haven't tried the conversion with a blowback yet, but by adding the ejector back I
m pretty sure it will based on past experience
DI 45 upper with Hydra M3grease gun mag well
8/14/2026 4:15:43 PM EDT
[#1]
What's the shortest barrel you offer?  
8/14/2026 4:42:23 PM EDT
[#2]
Rudy,
If a guy had your DI upper and bought a hydra GG magwell could they send it in for the needed modifications or if it's super simple could you give us a break down of what to do?
8/14/2026 10:50:05 PM EDT
[Last Edit: Mad-Machinist][Edited] [#3]
Quote History
Originally Posted By backbencher:
What's the shortest barrel you offer?  
View Quote View All Quotes
View All Quotes
Quote History
Originally Posted By backbencher:
What's the shortest barrel you offer?  

8 inch for DI

Originally Posted By Bye_Felicia:
Rudy,
If a guy had your DI upper and bought a hydra GG magwell could they send it in for the needed modifications or if it's super simple could you give us a break down of what to do?


Yep
8/15/2026 6:16:27 AM EDT
[#4]
Quote History
Originally Posted By Bye_Felicia:
Rudy,
If a guy had your DI upper and bought a hydra GG magwell could they send it in for the needed modifications or if it's super simple could you give us a break down of what to do?
View Quote
I had Rudy modify a straight blowback .45 barrel for the CMMG system for me years ago before I started doing my own barrel and this was for use with my MGI (now Hydra) lower with the GG mag.  All I had to do was removed the ejector from the lower.  Feed height was fine.
https://c3junkie.com/?page_id=841

What is kind of annoying though is no way to lock the bolt back on the MGI / Hydra GG magwell so I did the mod below.
8/15/2026 1:09:13 PM EDT
[Last Edit: Mad-Machinist][Edited] [#5]
On the magwell I was sent,  the upper wouldn't even close on the lower with the BCG without modification.  Trying to get in touch with Justin to work out logistics of a magwell based on the CNC AR 45 lower.....

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