Find fields & stores near you!
Find fields and stores
PbNation News
PbNation News
Community Focus
Community Focus

Thread Tools
Old 01-30-2013, 08:46 PM #1
Boom Master
Scenario Player
Join Date: May 2009
Location: St. Louis MO, USA, EARTH
The AutoRangefinder De-Classified

This was one of my first paintball projects to upgrade my marker. An Slide Mechical 68 autococker. Set up for sniping.

It is a aiming / sighting system that gets the elevation right for your ball pattern to drop onto the facemask of your opposing player at any practical paintball range. Up to 40 yards in this case.

It is a peep and post military style aiming system seen on many mil sim markers now. Tippman 68, BT, etc. It is a modification of that proven aiming system that also allows you to automatically determine the range of your target and set the elevation of the marker accordingly.

Here is the concept drawing.

The front post of the marker is replaced with a 2/56 threaded rod. 3-4 inches worth of post. You can always cut off the extra height.

How to do that depends on a LOT of variables mostly being what kind of marker you have and the barrel tip. How long the barrel is also matters. I used a 18" barrel.

I would suggest a mock up so you can figure out exactly the heights of the post and rear peep sight is configured to work OK.

The mock up for the front post is to get that threaded rod, bend a 90 degree turn on one end and hose clamp it to you barrel.

You will also have to RAISE the height of your rear peep sight. Again a mock up could be a piece of 14-16 guage copper wire, bend a circle on one end and hose clamp the other to the breech end of your marker. An electronic terminal piece could be soldered onto a wire as well.

I will add pictures and suggestions how you might go about a more permanent set up later.

For the mock up I would calibrate only the largest and smallest bead to determine the corrrect height needed from the center bore of your barrel tip.

You can bend the copper wire to change the height from the center of the barrel bore to WORK with the front beads and give you a good sight picture. Then you will know how high the back peep sight should be.

Roughly, the height you have to raise the peep sight is the same at the height of the largest bead. 2-2.5 inches.

Here is how I made the front sight.
You get various sizes of brass fishing beads from 3mm to 8 mm.

You drill and tap the hole in the brass fishing bead to match the 2/56 thread. Screw them onto the rod beginning with the smallest first and then progressively larger towards the top as illustrated below.

Then the fun begins. Having a helper makes this a lot easier.
Set up a steady bench rest set up for calibrating your marker's new sighting system.
Get a 1 gallon milk jug, fill it with water and put a paintball mask on it.

Have your buddy walk the jug out until the largest bead's size matches the size of the paintball mask top to bottom. Then set it down. Then take a trial shot with that bead lined up over the jug and in the middle of the field of view of the back peep sight. Like the illustration below. The ball will be high or low so you screw the bead up or down on the threaded rod until the ball drops right onto the facemask when lined up. Add one drop of super glue to fix it.

Tip: Hold the marker UPSIDE down so the excess super glue runs towards the top so you don't gum up the threads for the next bead.

Then do the next to the largest bead. Walk out until the bead covers the facemask top to bottom, set it down and shoot. Screw the bead up and down until the ball pattern falls behind the bead and onto the mask. Then the next smallest and so on. A drop of super glue to fix it.

Here is the real thing on my autococker. Used 2" thin wall glued to a PVC union that just happened to fit snugly on my All American barrel.

Yes, they are PINK. Powder coat and heat gun BEFORE I super glued them. Spray paint would have been a LOT easier. Hunters orange on the back. Flat Black on the front.

This project is not expensive or hard to do. The threaded rod and tap is available from almost any RC Airplane Hobby shop. The rod comes about 8-10" so you have enough for two. The mockup and final.

The copper wire is out of scrap household 120 volt wiring. I like the heavy 14 guage. Holds it shape better and bends more times without breaking. A foot of wire from LOWES will give you THREE of those wires. The ground wire is already stripped for you. Should be enough. or Scrouge a scrap from somebody. The electronic round terminal can be bought at any Autozone or Auto supply that carries lighting accessories. Paint it black with a magic marker or spray paint. Easier to see through. No glare.

So it is within your budget.

Now the BAD NEWS. In case you have not already guessed, it is labor intensive, especially to calibrate.

But worse than that, you will go NUTS trying to get your marker to shoot a very consistent velocity shot to shot. Plus or minus 5 fps is TYPICAL for field paint. That is about as good as you will get. Blowbacks like Tippmans vary MORE. You will have to maintain your marker as in cleaning and lubing much more than you are accustomed to. You will discover, you can actually chronograph your marker by adjusting your velocity screw until the ball hits the jug at that distance. The sighting system is simply MORE Accurate than your marker and paint will ever be.

So I would suggest you get your marker shooting as consistently as possible in terms of velocity BEFORE you calibrate it. And have your velocity just 5 fps under your local field limit. 275 for a 280 field.

My quest for consistent velocity including polishing my bolt and kept it SUPER CLEAN internally and externally. I invested in a hand held chrono so I didn't to go to my local field to calibrate it.

And you cannot use CO2 with this rangefinder. You have to use a regulated air supply. CO2 chills and the pressure produced varies tremendously during play. Varying pressure means varying muzzle velocity. You will go nuts with CO2

But it works.
Carefully planned irresponsibility is the KEY to mental health.

If you haven't grown up by age 50........

You don't have to......

Last edited by Boom Master : 01-30-2013 at 10:41 PM.
Boom Master is offline   Reply With Quote
Old Sponsored Links Remove Advertisement
Old 02-05-2013, 04:44 PM #2
joshsmithers's Avatar
Join Date: Dec 2010
Location: VA, for now...
 plays in the NXL
joshsmithers supports Team VICIOUS
joshsmithers is reppin' sidebar 4 life
joshsmithers has achieved Level 2 in PbNation Pursuit
This is one of the best paintball DIY write-ups I've ever read. The only thing I have to do is take your idea and apply it to my T9.1. It should work similarly, but I'm thinking I'll have to do it through a scope somehow because it will be hard to compare beads and masks at longer ranges.
Josh "Smithers" Smith
joshsmithers is offline   Reply With Quote
Old 02-06-2013, 08:55 PM #3
Boom Master
Scenario Player
Join Date: May 2009
Location: St. Louis MO, USA, EARTH
I have old tired eyes being a senior citizen. Everything is fuzzy from 18" to infinity without trifocals.

Yes the bead is fuzzy if you focus on the mask. and if you focus on the bead the mask is fuzzy but it is still good enough to work at the ranges we can get a break at. Do the mock up and see for yourself. It will be more accurate than your paint and hardware... Not ideal but close enough.

I tried putting it inside a 1 1/2 PVC tube with a 2" x 1 1/2" flare reducer fitting on each end to make it look like a ridiculously oversized scope. Mounted above the marker where you would put a scope. The front beads were MORE fuzzy but they did still get me in the ball park for those 40 yards shots. So I added a plastic reading glass lens from my Walgreens "readers" and stuck in inside the rear flare fitting. At least then my target was in focus. So you could do that.

Surprised a few players on the local rec field with how "lucky" I was.

The closer the front beads are, the more fuzzy they are when trying to focus on a target. Simularly, the farther away it is, the less fuzzy it is. So your long 18" barrel would work better than a short one.

I spent some considerable time on the internet trying to figure out how to do the optics like a scope does. The cross hairs are in focus inside the scope AND the target is is focus at 100 yards. It was way above my head. Made a few posts on forums with no response.. But I had the same idea of finding a way for the beads to be in focus as well as the target.

Plan D was a digital camcorder that could also take picture on a memory card. It also had a gimmick where you could put a picture that is on the memory card and super impose that with the video you are taking. Kind of a special effect thingy for baby pictures floating on a lilly pad. Anyway, I was able to make a bead picture and install it there so theroitically, I could reproduce that bead sight in the middle of the video display. Mount the camera on the marker. and bingo. Well, the wife vetoed the project but she hasn't used it in a couple of years and don't even know WHERE it is. So what she doesn't know, won't get me in trouble. Then I could VIDEO what the the range finder does while I shoot.

And everything would be in focus. The bead might be a circle with a facemask that fits inside it.
Carefully planned irresponsibility is the KEY to mental health.

If you haven't grown up by age 50........

You don't have to......

Last edited by Boom Master : 02-06-2013 at 09:01 PM.
Boom Master is offline   Reply With Quote

Thread Tools

Posting Rules
Forum Jump