Well, as I am in the process of "fixing" my gun and have it disassembled (see my previous, foolish thread for details , I'd like to look into the main reason I opened it up in the first place: the hop-up.
I understand that the MP7's hop-up is known to be difficult to adjust minutely, but from the start, this has been a huge understatement in my case. It appears that the hop-up adjustment is particularly loose (as in, you cannot set it in-between "clicks" or it will merely slide up/down to the nearest one with a little firing or temperature change -- though this may normal?), and furthermore, the clicks appear to affect the hop-up very little, if at all, until about the 5th, at which the gun still shoots quite low @ 100ft, even with .20's. However, by the next click, it kicks in very heavily, and the BB's curve up, even out to 150ft with .30's. Furthermore, no matter how far I adjust it upwards from this point, no additional spin appears to be added (not that it is needed, of course! But I thought it odd enough to be note-worthy). In short, my problem is that there is no happy medium at which I can achieve something resembling a straight trajectory. I am either shooting very low, with almost no hop-up, or extremely high, with too much. Now, I CAN set it perfectly if I very tediously position the hop-up between the 5th and 6th clicks, but it is so loose that within a few rounds it will rotate up or down to the nearest one.
I've tried using .20's, .23's, .25's, and .30's now, and I'm unable to compensate well for this problem, which I have had since I first received the gun.
Is this a common problem? Is there a way to make the hop-up adjustment unit tighter so that it doesn't move? Also, why, despite having so many "clicks" do the first 4-5, and the last 4-5 not seem to increase or decrease the hop-up; the only noticeable difference being at those two mid point clicks?
Edited by Hibiki, 28 January 2010 - 10:02 PM.