I would try to use a higher quality camera when doing gun reviews. Webcams won't cut it. Also I wouldn't do shooting tests. No one really cares for them or they tend to look down on them.
If you really want a lot of subscribers you need to post something exciting, like game footage or comedy acts. If you do just guns reviews or tiny project you won't get many subscribers. You really want to show the community why they should subscribe to you instead of just subscribing to billions of other airsoft reviewers. So in short keep your content fresh and different. If people have reviewed the same gun you have, I wouldn't bother to review it, because those videos have all ready taken up the hit counts from people who were interested in the gun when it came out
xxjomammaxx (my youtube) maybe you can take some inspiration from there
https://www.youtube.com/user/xXjOmAmMaXx?feature=mhee