Originally Posted by
Dorsai
This will probably be long, but hopefully useful. It may save you some money or justify spending it.
First of all, I modified my OEM stock by adding a QD socket to the left side of the stock so I could easily remove the sling and use it in the side sling position. I also drilled out the socket on the bottom where the Uncle Mikes style QD stud formerly existed and replaced it with another QD socket. Sometimes I like to carry it in a muzzle down African carry from the left shoulder. It worked well, but the Magpul stock and Aridus adapter was intriguing in that it couldn't be simply hype, there had to be some advantage. So like many, I was on a long waiting list before I acquired the stock and adapter. Almost immediately afterwards, the GG&G adapter hit the market and simultaneously the comment on bolt battering (still don't know if that is a real problem). So I quickly grabbed the GG&G unit. I have now mounted and handled all of them. FOR ME, the OEM stock with my modifications is better by a small margin, and I do mean small. So let me go through the details.
First of all, I'm 5'7", so a short LOP is important to me. The OEM Beretta is great. The Magpul with no extra spacers is just fine, with either adapter. For those of you with longer arms and excess height (lol), the Magpul stock is likely to be superior because you can adjust it. The Magpul grip is more vertical and you may prefer it. For me, it was a wash. I spent some time and money adding the QD cups to the OEM stock and the Magpul already has a loop for the sling and you can easily add a QD cup (which I did). So that is a big advantage if you aren't confident in your ability to, or have no desire to modify the OEM stock.
With the side sling over the right collar bone and around the back, it doesn't fit flat or tight to the body the way a rifle usually does. I noticed it more with the Magpul and at first I thought it might be because I was using the loop. So I got the QD cup and really didn't notice any difference. The sling positions in the stock are below the center of gravity and consequently the gun wants to rotate away from the body. My modified stock still does that, but not quite as much. Honestly, it probably isn't enough to make a difference. The sidesaddle also contributes to that both in weight and bulk. My conclusion is that it is subjective and consequently, the individual's mileage may differ. You won't know until you've tried it.
I recently (finally!) got the Aridus CROM (Aimpoint version) and it lives up to the hype. I had tried mounting a Holosun on the factory pic-rail and rear sight and it just sat too high. No co-witness and I didn't like the cheek weld or lack thereof. The CROM on the other hand does allow a co-witness. My experience with the Magpul stock was that is just a little low. I got the Magpul small comb kit (1/4" and 1/2" risers). The 1/4" higher comb works well. Shouldering the gun put the dot (actually, a circle-dot like the Eotech) right in front of the eye. Scrunch down a little and I was looking through the ghost ring. The OEM stock is very slightly lower, so a smidge higher head position is in line with the dot, a smidge tighter on the stock works for the ghost ring. Keeping in mind that not everyone has the same cheekbones as I, YMMV.
I didn't feel any difference in feel between the Aridus and GG&G adapters. Installation is slightly different. To remove the OEM stock, you unscrew the buttpad with a thin Phillips head screwdriver. The nut that retains stock unscrews with a 13mm socket and extension. Remove the stock and use a wrench to unscrew the buffer from the receiver. The long stock retaining bolt is actually a rod threaded on both ends, so it can unscrew from the buffer.
The Aridus adapter has a bolt that screws into the same hole. Unlike the GG&G, it does not have a buffer and is a little harder to start without cross threading. For both, put the adapter on the receiver, position the stock on the adapter and attach it to same socket headed bolt/buffer you installed in the receiver. It installs through the top of the wrist with a hex wrench. Bottom line is that the Aridus adapter is thinner than the GG&G and doesn't have a buffer. I didn't notice any difference in how they felt when mounted. I think you'd need two shotguns handy, one with the GG&G unit, one with the Aridus so you could quickly swap them back and forth before you could tell a difference, if then. Considering the length of time it takes to disassemble and then re-assemble, my memory of the feel disappeared.