I now have at least 300 rounds through my 10" AR-V running a Maxim Defense RDB and a Timney drop-in trigger designed for 9mm. Here are my thoughts and findings.
Maxim Defense RDB: When I received my ARV a few weeks ago I took it to the range to give it a run with in a completely stock configuration. It’s about 2 pounds lighter and 6" shorter than my Scorpion carbine. I ran about 50 rounds of competition hand loads as well at the same number of factory ammo. As I expected, it gave me the peculiar 9mm recoil that isn’t painful, but it is jumpy and unpleasant. I also found that the hotter factory ammo increased the bolt cycling rate, which was easier to keep to make follow up shots. Once my SBR paperwork comes through, I plan on using this firearm for USPSA competitions, so that’s important. The trouble is, it cycles quicker, but the 9mm recoil makes it jumpy, so it’s harder to keep on target. After reading a ton of reviews I decided on the Maxim Defense RDB. When it showed up, I was impressed on the quality of the machining and assembly of the device. I did however find it difficult to install. It should be easy, but after removing the bolt weight and original buffer and spring I started pushing in the RDB. I found that it would only go so far, then stop. After a few seconds I realized the coil spring was getting hung up on the ejector. The only options I could see were to remove the ejector, remove the buffer tube(which is staked) or try to compress it a lot by hand to clear the ejector before insertion. I went with the latter. It was like trying to wrestle a greased pig, but it finally went in and clicked behind the buffer retainer pin. Sheesh. The next time I’ll just remove the 2 ejector screws. I went to a local falling steel fun match the following weekend and ran another 200 rounds of mixed hand loads and factory. I was astonished by how well the RDB worked. It was a completely different firearm. Now the hotter ammo not only cycled quickly, but also came right back on target.
Yes, it is much harder to charge the bolt, but it’s not all THAT hard. I recommend an ambidextrous charging handle with large wings.
Timney Drop-in 9mm Trigger: I also dropped in a Timney 3 pound, flat faced trigger before the fun shoot. I run a Timney designed for the Scorpion carbine and it completely changed the nature of the carbine. As expected this one was also much better than the stock trigger that comes with the AR-V. Using a trigger gauge the trigger measured 2.65 lb. The trigger reset is very short with a tactile click. All good stuff. However, I don’t think this trigger has a strong enough trigger return spring. I found myself short stroking it a few times. I didn’t have this with Scorpion version. This isn’t a big deal, and I’m sure I’ll adjust, but it’s the one ding against this trigger.
That’s it folks. Hope this helps when you decide to upgrade.