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Discussion Starter #1
What options are available for a rail mounted laser (Red or Green)? I am looking for a good laser that holds zero, but is not super expensive anyone?
 

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You really only need to consider a laser for indoors. An expensive long range laser is unnecessary on a home defense 100 yard gun. So you need the tiniest, inexpensive yet effective laser you can find. Perhaps a crimson trace? Or a TLR light laser combo. Try to get green over red as the eye naturally picks green up better than red. My two cents, its actually a relatively hard question to answer, nothing specific came to mind for me.
 

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I struggled with laser mounting on my PS90. Anything mounted on the factory rails is not going to be too accurate because it is too far from the bore. What I ended up doing was making my own mount that attaches to the factory screw locations and allows the laser to be mounted directly below the barrel. I went with a Crimson Trace CMR-206. Makes for 1 more step to clean the rifle, but it holds zero really well.

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Discussion Starter #4
You really only need to consider a laser for indoors. An expensive long range laser is unnecessary on a home defense 100 yard gun. So you need the tiniest, inexpensive yet effective laser you can find. Perhaps a crimson trace? Or a TLR light laser combo. Try to get green over red as the eye naturally picks green up better than red. My two cents, its actually a relatively hard question to answer, nothing specific came to mind for me.
i am not looking for a long range laser. i am looking for either a red or green laser that holds zero for use from point blank range to 25 yards. that is not super expensive. I was going to contact Crimson trace to see if any of their lasers can be mounted on a pic rail
 

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Discussion Starter #5
I struggled with laser mounting on my PS90. Anything mounted on the factory rails is not going to be too accurate because it is too far from the bore. What I ended up doing was making my own mount that attaches to the factory screw locations and allows the laser to be mounted directly below the barrel. I went with a Crimson Trace CMR-206. Makes for 1 more step to clean the rifle, but it holds zero really well.

View attachment 129033 View attachment 129035 View attachment 129037
unable to view the picture
 

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Can't see the picture.

I wish there was a way to modify a pistol laser from say, Crimson Trace or Viridian, to use as an internal laser.

I like how Promoted Pawn has accomplished this, except for the laser used itself. If there was a way to get a tiny pistol laser to fit inside the PS90 stock somehow, and then have the wiring to reach the back toward the buttpad in the space above the trigger pack, it would be easy to change batteries from there. It would require stock modifications and wires being ran, similar to how Promoted Pawn does it, but at least the laser itself wouldn't be a budget breaker and would be easily serviceable.
 

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Discussion Starter #8 (Edited)
i would really like to see the laser setup you are talking about on your PS90. I am almost godlike with my DD/Colt MK18, but my favorite firearm by far is the P90. I am trying to get a 2nd one so I can SBR it for my daughter to train with.
 

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Discussion Starter #13
Bringing my old topic back to life. I am still looking for a side rail mounted laser. The ranges I would like to have it zeroed for would be 7 to 15 yards. The reason a low light situation or not a direct line of sight while aiming situation.

I am curious to the Lasermax Micro II with a green laser. It has a after 10 minutes of use auto shut off, and 5 hr run time. I wanted a light weight, small and not super expensive laser system for my PS90 SBR.

If anyone is using this laser or similar type please fill me in on your personal pros and cons.
How much of a POI shift there is at different distances ( which I sure there will be with a side mounted laser)
Your preferred zeroing distance with your laser etc.
 

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Bringing my old topic back to life. I am still looking for a side rail mounted laser. The ranges I would like to have it zeroed for would be 7 to 15 yards. The reason a low light situation or not a direct line of sight while aiming situation.

I am curious to the Lasermax Micro II with a green laser. It has a after 10 minutes of use auto shut off, and 5 hr run time. I wanted a light weight, small and not super expensive laser system for my PS90 SBR.

If anyone is using this laser or similar type please fill me in on your personal pros and cons.
How much of a POI shift there is at different distances ( which I sure there will be with a side mounted laser)
Your preferred zeroing distance with your laser etc.
The POI (Point Of Impact) shift is somewhat complicated to figure out.

At zero and ONLY at zero, the POA (Point Of Aim - in this case, the laser point on the target) is POI (Point Of Impact - bullet hits bullseye). Any other distance off of zero (+A and -A projectile arc, along with +B and -B, projectile distance before and after zero) and you have some major calculations to make in the X and Y planes. Just measure the offset from bore of the barrel to the laser Point of Origin (POO). Lasers travel in a very near straight line (atmospherics play hell with lasers over distances). Don't forget there are two measurements of the laser line of sight (LOS), both height and offset (Y and X plane). Lets say the laser POO height is 3 inches (Y) higher than bore, and the offset is 2 inches (X) off of bore. If you set the POA of the laser to be zeroed at 7 feet (in reference to the projectile flight path or arc), then at 14 feet, the POA of the laser is 3 inches low (Y) and 2 inches off bore (X) depending of which side you place the laser while negating the projectile arc of travel. Add another 7 feet (21 feet) and now its 6 inches low (Y) and 4 inches off bore (X) again, negating the projectile arc of travel. Now take the bullet trajectory (projectile arc of travel) into consideration. The projectile is in a positive arc of travel (+A) in reference to the Y plane but will eventually go into the -A arc of travel in the Y plane, so in reality the height of the laser which is your POA in reference to the travel of the projectile at 14 feet is much more than 6 inches low (Y), is is more like 9 inches low (Y), while the offset remains the same because the bullet trajectory is in the Y plane (+A and -A) only (above and below the POA) and not the X plane (side to side where wind is involved in the calculations, the offset). So now anything off of zero and you have to calculate +A or -A, +B or -B, X and Y depending on pre or post zero.

You should be thoroughly confused at this time......::FF:: Although I am pretty sure that you have already figured most of this out.





I had a laser mounted on the side of my receiver on the PS90 SBR and hated it because the laser was only accurate at the set zero. I had it zeroed at 50 yards so the offset in both the Y and X planes were not as pronounced. So I removed the laser and spent the bucks to get a laser that mounted right under the bore, ie the Lazerex P90 laser. Directly above or directly below the bore is the only place that a laser belongs on the PS90/PS90SBR, and even with that, you still have to worry about projectile trajectory (+A and -A) which varies on which ammo you use over distance (+B and -B) and wind calculations (+C and -C).

All lasers are only good for 1 distance (zero) with 1 ammo choice (ammo used to zero) while trying to negate any other effects. Any other distance or ammo choice requires additional mental calculation for the POA of the laser to be the actual POI of the projectile. So in the above example, at 14 feet, your POA for the laser has to be 3 inches high and 2 inches offset (depending on which side the laser is on) and this STILL DOES NOT take projectile calculations (+A and +B along with -A and -B) into consideration, to hit the bullseye, which of course will vary depending on which ammo you use that was not used to zero the firearm. Now you have another variable or a different +A -A +B -B for each different ammo you use in relation to the Y and X plane of the laser POA.

Now imagine that your laser is on the side of the receiver and we will negate the offset at this time. Using the above charts, if your laser is 3 inches high off bore and you set your zero at 50 yards, simple draw a line on the 50 yard zero chart that starts at the point +3 (over bore) and intercepts the laser POA from +3in to bore line of sight at 50 yards (your zero), and you can see the massive descending line of sight (LOS) of the laser Y versus the amount of arc travel in the +A plane of the projectile. You can do the same with the 100 yard zero and the bullet trajectory will more closely match the projectile flight path (after zero intersection) than at 50 yard zero. Remember, the offset X has been negated in this example. If you extend the line further, you will see that eventually the arc of travel (now -A) will eventually intercept the laser LOS in the Y plane. This is akin to what was learned while zeroing the M15/AR15 using ball ammo.....if you zero at 30 meters, you will again be zeroed at 300 meters. This works with all firearms with all ammo because the projectile travels in an arc due to the effects of gravity.

Simply, you are working in 3 dimensions with 2 different flights of travel (Laser POA X=Offset, Y=Height, Z= Distance (XYZ) and projectile arc trajectory AB). This is what snipers have to worry about so instead of a laser, they use a scope, which at least is adjustable, so they can calculate the POI at the POA. At least the scope has an adjustable X and Y plane (MOA/Mils in both planes) which calculates Z (thus eliminating A and B), whereas the laser is ONLY good at a single location using a single ammo type. This is why marksmen have ballistics charts for each type of ammo for EACH firearm, not each type of firearm. And ballistics charts change each time a rifle is fired, it is minuscule at first but gets worse and worse as the neck erodes in the rifle barrel. However, there are now new scope like lasers that because they can calculate Z distance, they also can calculate Y and X along with A and B and put a projectile on target at any distance using any ammo out of any firearm. This is point and shoot with a mini computer doing all the calculations.

My head hurts and I still may not have gotten this completely correct......

This is akin to orbital mechanics when you actually do the math calculations. After all, an orbit is just a reversal of arc of travel, unless you are geostationary, then it is travel without movement in relation to a point on the plane.
 

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Discussion Starter #15
wow a lot of info there. I wanted to have the laser zeroed for 7 10 or 15 yards only (one of those) and i was going to see POI shifts at a indoor range for each distance.

The reason I want a laser is for low light or shooting from off positions ( around a corner or above furniture or vehicle etc) The laser would just be a tool in the tool box. A backup if my light goes down or both my light and optic vs using the backup irons on the top rail that are not very good at all.
 

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wow a lot of info there. I wanted to have the laser zeroed for 7 10 or 15 yards only (one of those) and i was going to see POI shifts at a indoor range for each distance.

The reason I want a laser is for low light or shooting from off positions ( around a corner or above furniture or vehicle etc) The laser would just be a tool in the tool box. A backup if my light goes down or both my light and optic vs using the backup irons on the top rail that are not very good at all.
You can do an educated guess and get near a hit when the target is near zero. It is more complicated if your distance varies from zero. A backup to a backup to a backup...... Lasers are point and shoot or else they are pretty useless. I rely on my laser much more than my ring sight with the REM. Because in BOTH cases, the sight and laser are line of sight, not line of projectile travel. The laser has the advantage because I have a dot on the target and it is more point and shoot. You have very little time in an active shooter situation to take aim and worry about not hitting the target. With a laser on the PS90SBR, center of mass aim will result in a near center of mass hit.
 

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Discussion Starter #17
that is what i was curious about i think i will zero a laser ( when i get the one i want) for 7 yArds and check the impacts at cqb to 15 maybe out to 25 to see how much of a hold over or to the side i will need to do at different ranges. Hopefully most will be center mass
 

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that is what i was curious about i think i will zero a laser ( when i get the one i want) for 7 yArds and check the impacts at cqb to 15 maybe out to 25 to see how much of a hold over or to the side i will need to do at different ranges. Hopefully most will be center mass
Changes between POA and POI are smaller with a longer zero. I would recommend at least a 50 yard or 75 yard zero. The biggest concern is how far the offset in both planes the laser point of origin is to the bore of the rifle. The more variation of distance between point of laser origin and bore, the bigger the variance in POI will be. This is why I opted to put out the bucks for a laser that sits directly below the bore of the barrel.
 

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pos and poi for the regular zero (the optic) with min shift at longer range?
I assume you mean POA not pos....

No because they both work on the same principle. Line of sight vs projectile trajectory. When you aim through a sight, it is a straight line aim...just like the laser. With a laser, you see where the sight line terminates. With the sight, it is imaginary. So if you are looking at the laser vs the sight, the laser has the advantage if it is very near the bore because it puts the dot on the target, whereas the sight puts an imaginary dot on the target. So the laser has the advantage because you see very near where the projectile will hit. With the sight, you are just guessing that your LOS aim is where the projectile will hit.
 
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