I’m just curious how many of you have actually had a receiver extension fail, or personally witnessed a failure. Did it strip free from the receiver enough to malfunction, or did it bend enough to seize the bolt or buffer?
The reason I ask is that I am currently running an Ace M4-7 Heavy Duty Receiver Extension. I chose this particular one because I believed it to be stronger than standard mil-spec RE’s. I have since learned that there are some features about these extensions that are less than optimal. They are constructed of 6061 aluminum and are commercial spec so their threads aren’t fully engaging the receiver’s threads. I also found that the OD of the tube is undersized enough that a Magpul CTR is not rattle free even when locked down. This wasn’t a big deal to me as I ordered a Choate stock with storage tubes in mil spec, which are notoriously over sized, and modified the inside of the stock just enough to fit so the combo locks up very tight.
While I believe that this set up is more resistant to bending or warping, I am not at all certain that the extra strength is really necessary. How likely is an RE to get bent or broken even under hard use? Is there a greater probability of stripping the threads on this tube if I take a hard fall on it, considering the material and the commercial dimensions? If so I am running a heavier set up than I need to be with no real benefit.
I understand if you are inclined to suggest that I run the setup as is until there is a problem, but I really want an answer from a technical perspective, and this is also my only carbine so I want it as bomb proof as possible. I am just curious if I have misguided my efforts , or if there is not a real likelihood that it will ever be an issue in any case. Thanks for your time, and I would greatly appreciate your feed back.