The F4 Sidemount Sight
In the time that I've had my webpage up, I've gotten a number of inquiries with regards to the side-mounted red-dot sight on my F4. It seems that many people like the idea and would like to know how I did it. If you're one of those people, you'll be happy to know that it was very easy to do.... Sort of.... By that, I mean that I've actually built two different side mounted rails for the F4. The first one was a quick and dirty model that was very easy to manufacture and install. The second model was a great improvement over the first, but the skill and equipment required for manufacture is a quantum leap over those required for the first model.
That said...
If you're going to put a rail for side-mounted sight on your gun, the first thing you've got to do is find something to attach your rail to. Duh! If you've an F4 handy, look at the left hand side of the receiver. What is that little thingy attached there? It's the ball detent cover plate. And what holds the detent plate on? Two screws.
Now, imagine for a moment that you pulled those two screws out and replaced them with a couple longer screws. Why, I bet you could stick something onto your gun with them screws.
The ball detent cover plate and the screws that
hold it in are clearly visible on this (modified) F4
found on the
F4 Owner's Group website.
Great! Now you've got the basic idea...
The first thing you're going to need to do is measure the distance between the two screws on the detent plate (I would just tell you, but it's been long enough such that I don't trust my memory!).
With your newfound knowledge of your detent plate, go to a gun store and ask to look at dovetails. Find one that has two holes that are spaced that magical distance apart. I used a Weaver model 62 dovetail, but this probably won't work for you. Why not? Because it's a 7/8" dovetail. Most scope ringss these days require a 3/8" dovetail - I just happened to have a 7/8" set and so what worked form me probably won't work for you.
Now, look at the "bottom" of your dovetail. The surface is concave, no? This is bad. You need something that will rest flush up against the top of the ball detent cover plate. So here's what you do: Go to the hardware store and purchase a gelled epoxy that won't run. Prep the surface of the dovetail as per directions and fill the concave surface of your dovetail with epoxy. Once the epoxy has cured, sand it down such that you've a nice flat surface on the bottom of your dovetail. Now you'll probably need to re-drill the holes in the dovetail as they've probably got some epoxy in them - no big deal.
While you were at the hardware store you did remember to pick up a couple of long(er) screws that match the size/threads of the factory screws that hold on the detent cover plate, right? Great. Now, just use those screws to affix the dovetail to the gun by going through the dovetail, through the detent cover plate, and into the gun. Note that you might need to trim the screws a bit - the odds of getting the perfect length screw from the store are pretty minimal.
Now all you've left to do is mount your scope to the dovetail just like 'twere on top.
When complete, you should have something that looks like the setup seen below. The primary advantage of this system over a "normal" raised system on the factory dovetail is the fact that the scope ends up being a good 4" lower. So what? Well, that means that when you're shooting over the top of a piece of cover (a fallen log, for example) you can keep your head 4" lower than the other guy...
Having played a few games with the above sight rail, I noticed a problem. At longer ranges (when the sight was needed most) the sight was largely useless because the paint would drop below the sight picture. This was due to the fact that my red-dot scope was intended for use on firearms; i.e., weapons that employed much flatter trajectories. The only way to fix this would be to tilt the entire scope downward about 1 degree.
And so I endeavored to machine a custom sight rail that would attach to the side of my F4 and include a 1 degree downward slope. This slope would be such that the balls impacting at about 100 feet would be centered in the sight picture, thus making the scope very effective at long ranges (for paintball, anyway). In addition, I moved the scope back as far as I could to allow my eye to get as close as possible to the optics. This makes for easier target acquisition.
Construction was straight forward for anybody with access to both a horizontal and vertical mill. If you've such access, I'm sure I need continue no further. If you've no such access, the details won't do you any good.
Suffice to say that the results are wonderful!
