TL DR: It will probably work but buy at your own risk. Not recommended for reinforced gearboxes.
AR latches are simple creatures, and with a brand like Retro Arms that commands quality with the name, why the 3 star?
Simply put, I ran into a compatibility issue. I have had compatibility issues with AR latches before. Such as shaft lengths not being design for a blind recess ( Lonex V7 ), or the latches themselves buying being physically too tall like generic ACM ones.
While the Lonex experience is disappointing, it isn't a shocker given their reputation. I have a lot of hit/miss experience with Lonex.
But, Retro Arms takes engineering seriously, in my opinion. They are always trying to innovate, and add really good features that are good for the industry and I appreciate the work that they do. But this is also why I will be more critical toward them.
On their website, in some blog post or so, they mention that manufacturing airsoft or doing maintenance of airsoft products is difficult because there is no universally defined standard. They quoted an example like ISO. I don't disagree, I have probably lost thousands of dollars to parts that just didn't work and there is no repercussion to that which is extremely unfortunate.
But with that sort of "complaint" from Retro Arms, they proceeded to design and manufacture this latch. A non standard shape and size that has cost me a lot of time to install.
I have build hundreds of gearboxes. It is rare for an AR latch to be the issue, but it is usually immediately apparent. Either the shafts are too long expecting a through-hole, or the latch itself is just too thick for the entire gearbox. When you go to close things up these incompatibilities become obvious.
But, the Retro latch was close enough, that the actual fault took a few days, couple of hours per day to find and fix because they simply chose to not clone an existing design that has been around for literally decades.
I find it extremely ironic they they want a standard, and then proceeded to create a standard that is a little less than universal.
Don't get me wrong. It was close.
The shaft fit was pretty tight, but good. It was so tight that when I added grease to my blind shaft, the seal was so tight it actually compressed the air in there and pushed the ar latch back out. This, is probably not a good thing, but I thought it was cool and it ultimately was not my issue.
But I thought it was related so I very carefully opened up the gearboxes shafts to try and reduce potential friction.
I spent hours on this iteration too and got nowhere.
Next, I have oldschool Siegetek 14:1 gears in this build, with the bevel teeth going all the way up. I like this design a lot, personally, but Siegetek does note shaving the AR latch is required to prevent the latch from slipping.
So I spent a few iterations doing this until I was so convinced the contact is positive and reliable that neither of these issues had to be it.
Finally, I noticed a small gouge mark on my gearbox shell. Turns out, the latch was being pinched just enough to cause it to behave sluggishly and unreliably. Filing this section of the gearbox down fixed the issue.
So, who is to blame, Retro Arms? Or the V2 manufacturing cloning the TM spec. In my opinion, this is an instance of over engineering resulting in an issue. The latch is simply too thick, and too large to be universally compatible. Because literally any other latch would have worked in this gearbox shell, like Lonex or AZ tech, or any generic ACM latch.
Similarly, other latches for the same price point even have more features if you can believe that. Modify, while not having the "COMPSRING" has a flat head slot for latch releasing. AZ Tech has both.
In my opinion, there is zero reason to buy this latch. It will likely work, but other latches are MORE likely to work. If you MUST spend this price point, there are better AR latches out there.
This judgement also comes from a place of privilege, admittedly, but lets assume the argument would be made that Retro latches are compatible with retro gearboxes guaranteed. I believe that, but, if you can afford a Retro CNC gearbox, you can probably also afford a motor with one way bearings so you can just delete the latch entirely and save yourself some money. You're already spending a premium on this product. If you cannot afford both at once, but you know you are going down that path, then temporarily use an ACM latch while you get more funds together instead of blowing money on a latch that you might not be able to use elsewhere.
The final cherry on top is I value my time. Any other latch would have just worked, probably. But after hours of troubleshooting, that makes this already expensive latch extremely cost prohibitive to use. I buy premium for less headaches, not more.
I will still actively buy and support Retro products, of course. They have solid products and ...
