Q&A for FM Products FM-45 AR .45 Rear Charging Upper Reciever, 5 inch w/ Blast Diffuser — 9 Questions & 8 Answers

This FM Products FM-45 AR .45 Rear Charging Upper Receiver as well as most FM products require the use of a buffer assembly. However, FM Products has just released a newly designed upper chambered in .223 Wylde that does not require the use of a buffer assembly due to the redesigned recoil system. That upper can be found by using the link below:
https://www.opticsplanet.com/fm-products-fm-15-223-wylde-mid-length-gen-2-upper-reciever.html

The manufacturer states that the FM Products FM-45 AR .45 Rear Charging Upper Reciever is compatible with any AR Pistol Caliber lower that accepts Glock Magazines.

The FM Products FM-45 AR .45 Rear Charging Upper Reciever barrel is threaded for 5/8x24 so you could remove the blast diffuser and mount a suppressor. However, the handguard will protrude over the threads and the inner diameter of the handguard is 1.3".

The FM Products FM-45 AR .45 Rear Charging Upper Reciever should be compatible with the FM-9 lower receiver. According to the manufacturer the FM Products FM-45 AR .45 Rear Charging Upper Reciever is compatible with any pistol caliber lower that accepts Glock Magazines.

Yes, the FM Products FM-45 AR .45 Rear Charging Upper Reciever comes with a BCG and charging handle.

The internal diameter of the FM Products FM-45 AR .45 Rear Charging Upper Reciever handguard is 1.3". So the AAC Ti Rant 45M will not fit the FM Products FM-45 AR .45 Rear Charging Upper Reciever.

The FM Products FM-45 AR .45 Rear Charging Upper Receiver is chambered in .45 ACP. This upper features
Non-reciprocating fixed forward charging handle
Left or right side charging
716” 4150 chrome moly barrel
6.75” monolithic free float handguard
M-LOK attachment points
Continuous picatinny top rail
.45 ACP bolt carrier group included
FM products muzzle brake with 5/8x24” threads
Compatible with Glock magazines