Well I was looking on-line for a new hopper and I purchased the 12volt Revvy. I received that from the mail maybe.. a week later and I tried putting the hopper into my ION and.. It wouldn't fit.
I decided I needed a clamping feedneck so I looked around on-line, I knew what I wanted anyways, but I just wanted to check around.
I couldn't find anything I really wanted so I went on Lapco's site and ordered a new clamping feedneck. I received that in the mail in a couple of days and screwed it in and put the hopper on. I tightened the feedneck with an allen wrench and it stayed on really tight.
I did notice that the feedneck kind of wiggled around a bit, but that wasn't a big deal so I just put some teflon around the threads of it and screwed it back in and made sure there wasn't any teflon by the bolt. And there wasn't.
Now that I have everything tightened and secured I know that I will definitely be able to own some bodies out at the field without having to worry about my hopper falling off.
If you are looking for a locking feedneck then look no further, buy it. This is a GREAT investment on my part and you won't regret it!