Laser is 8" off at 20', 18" off at 50'?! This normal?

[David007]

I bought an el cheapo $25 laser to put on my Ruger Mark III (.22) for the fun of it.

The ruger isnt a target model, thus no rails. i just use an adapter and clamp onto the underside of the barrel.

Something similiar to this:


anyway, at 20' the laser is 8" lower than where the bullet hits. so i have to aim at the bad guys stomach to get a chest shot.

at 50' it's like 18" lower. so at the range, if i aim at the bad guys stomach, i might get a head shot

For those w/Crimson trace (or other reputbale laser), does the distance between the laser and where the bullet hits increase as target distance increases?

And is there a way to fix this? or at least minimize it?

thx!

 

[rcmodel]

Doesn't the laser have any way to adjust the zero??

All decent laser sights have two screw adjustments to set the windage & elevation to the gun it is mounted on.

If your Ruger has a tapered barrel, the laser will not be pointing where the hole in the barrel is. But that should make it shoot lower, not higher.

If yours doesn't have W & E adjustments, you could shim under the mount to change elevation.
You need to tilt the laser up to make it shot to the dot, so put a thin card shim between the back of the clamp and the barrel.

As for distance & POI remaining the same?

If the laser is off-set from the bore axis, it can only coincide with the bullet path at one distance.
The thing is though, it is impossible to see a red laser much past 20 yards or so in sunlight.

So if you zero at that distance, the bullet will be very close to the bullet path all the way out to 20 yards, or as far as you can see the dot in daylight.

You probably should not be shooting past 20 yards in the dark.

rc

 

[writerinmo]

The super-cheapo lasers aren't adjustable and a total waste of money for anything other than a toy to get the dogs to chase...

 

[The Lone Haranguer]

Another factor - albeit a smaller one - is that the trajectories of laser beams and bullets are not the same. The laser is straight, while a bullet follows a flattened parabolic arc path. If you get the laser and bullet paths to intersect at 20 feet, the laser will be higher at 50 feet (due to the bullet having dropped), the divergence increasing with range. (This is assuming you are able to - eight inches at 20 feet is an awful lot.)

 

[eddism]

Shim it till its right if there isn't anything else to adjust it.

 

[Salty1]

It looks like that laser is one of the ones made in China and sold through CDNN, if so your better off utilizing it as a dog toy as mentioned. Everytime you shoot it will move. El Cheapo is cheap for a reason, the old saying that you get what you pay for holds true 99% of the time..... I had one of these that came free with a rifle I purchased, had it zero'd at 50 feet, every single shot made the zero move, after 5 rounds I stomped it and put it out of it's misery and kept my sanity intact.....

 

[eddism]

Small price to pay to keep One's sanity

 

[Kruzr]

Rotate it and you will see the laser move. Since you can't zero it, you will have to rotate it until you get closest. At distances other than the one you "zero" at, it will be low closer in and high further out.

 

[HK-Freak]

The POI for all lasers is going to be either high or low unless your target is at the exact distance your laser was sighted in at. For example; if you sighted your laser in at 10 yards, than anything beyond 10 yards is going to hit low, and anything closer than ten yards is going to hit high (this is assuming that your laser is mounted below the barrel. If it's above the barrel than your POI will be just the opposite). Your laser looks like it's mounted fairly low below the barrel, so your POI is going to be off a pretty good amount (of course, since you can't adjust your laser, there's not a lot you can do about it).

 

[wh!plash]

Easiest way to explain it is by drawing a quick diagram:

Its basic geometry if you think about it. Your bore and your laser are mounted next to each other, but they aren't the same 'line' (ray in geometry terms). They have to be set so that their paths converge at some point, and thats the only place you can expect the bullet to hit right 'on the red dot'.

The only way you could set it so that its the same regardless of distance is when your bore and laser are running parallel paths. But in that case, the bullet will always hit just off from your laser, but always by the distance that actually separates your barrel and laser.

In the case you describe, your laser is mounted below the rifle, but your laser is aimed the opposite direction as my diagram. The laser is aimed lower, so there's no point where they cross paths. The laser is just going further and further from your bore as it goes.

If you know your geometry and trig, you can use my diagram to calculate how far "off" your dot would be at a given distance. Lets say you sight your laser for 15 yards, and your laser is mounted 2" below your barrel. That means at 30 yards, your going to be hitting 2" below below your laser dot. You can see now that if you're thinking a laser is a cheat to help you shoot a fly off of a gnat's ass, you're going to be disappointed. But for quickly acquiring and hitting a human-sized target in a high-stress situation, the margin of error in the laser is going to be negligible.

Oh another thing to think about. If you have a laser that mounts directly under your bore, you only have to think about the up/down relationship of the dot. Now think about something like a Crimson Trace grip. Its actually slightly below the bore, and slightly to the side. Now you've got to approximate two dimensions if you're aiming the laser at something closer or further than you're sighted-in distance.

 

[Dulvarian]

I put a Burris Fastfire II on my Neos, holo sight vs laser, but it works great. Especially for the kids. Oddly, that little .22 hammers the crap out of that sight. I had to Loktite all the screws down because I couldn't even sight it in it was shaking the screws out so bad.