# DealExtreme 20mw green gun laser



## killforfood (Jul 6, 2007)

Does anybody have any experience with this laser?













I'd like to mount this on a shorty AR15 for some nightime bunny boppin.
My main concern is if the aiming rings are real or just fake like I've seen on other cheap lasers.


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## nerdgineer (Jul 6, 2007)

Don't know anything about it. Maybe it's just me but for a weapon light, I'd prefer a red (or some other color) single diode laser over a greenie because of the inherent fragility of the 3 cascaded lasing components required for a typical DPSS greenie.


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## killforfood (Jul 6, 2007)

nerdgineer,
I wasn't aware there is a difference in the way different colored lasers are designed. 
If these are fragile, I'd sure like to know?
My reasoning for wanting a green laser is the ability to see the beam and track it to the direction it's pointing. Red lasers seem to have an invisible beam and some times your point of aim has to be searched for.


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## nerdgineer (Jul 6, 2007)

I'm not the expert, but basically, there are a limited number of materials which can be used to make a solid state laser diode, i.e. something which will lase when electricity is applied to it. Only a limited number of laser colors can be produced this way, mostly reds and infra-reds. Nothing will make a green single stage laser diode.

To get a solid state (as opposed to gas) green laser, the designers use a trick: they start with an infra-red laser whose output is pumped into a second crystal which - when excited by the infra-red, will lase at another frequency deeper in the infra red. They then pump the output from the second crystal into a third crystal which then lases at twice the frequency of the incoming laser beam (only for a laser frequency near the second IR laser's output). Twice the IR frequency gives you green laser light.

All this requires that 3 lasing crystals and a set of optics be carefully aligned for it to work. A single stage laser (i.e. red...) requires only that a single laser diode be aligned with the optics, which is much easier to do and cushion against shock. The green is thus inherently more delicate because of its many more lasing parts.

It is POSSIBLE that the laser you show is isolated well enough to withstand weapon firing shock; but if it were, I'd expect it to be VERY expensive (like a set of Leitz camera lenses...). Otherwise, I'd expect it to be unacceptably fragile.

Check out DPSS laser design in wikipedia for more. 

Just my 2 cents. And as I said, I actually don't know ANYthing about the specific laser you show.


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## killforfood (Jul 7, 2007)

Well, I posted my question on Dealextreme and got a quick answer back from Fernando.

*killforfood *Friday, July 06, 2007 11:53 AM Reply I've seen on some of the cheaper lasers that the point of aim cannot be changed because the aiming rings are fake. 
Are the aiming rings for real? 


*Fernando @DX *Friday, July 06, 2007 10:41 PM Reply no, that part is not functioning. Maybe just a decoration. 

I guess I shouldn't be to suprised since it's about the lowest priced green gun laser on the market.
I think I'll lay off buying one until I get a better idea of who makes one with a good aiming system.

nerdgineer,
Thanks for the excellent green laser primer.

It's funny, I use a laser system on a regular basis at work but never really sat down to learn the hows and whys. I just plug it in and go. I use it to measure and correct linear distance on precision measuring equipment.
One of the larger CMM's (coordinate measuring machines) that I maintain actually uses lasers for the linear scales.
Over time it has become more difficult to maintain adequate signal strength. Some of this can be corrected by cleaning dust from the interferometry optics or by re-alining optics but after reading posts by some of you power hungry crazies, I wonder if there's a way to just PUMP IT UP!

If any body knows how to overdrive a Spectra physics 117B laser let me know. They only cost about $17,000 (it's not my money :thumbsup each and I have 3 or four spares on the shelf, so lets be brave.


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## nero_design (Jul 7, 2007)

Looks a lot like the one I recently purchased online on EBay. It's true output is 30mW but it states on the front of the aperture casing (erroneously, I might add) that the laser is a 20mW Class IIIa 650nm laser but instead is actually a 30mW Class IIIB 532nm laser. I can only suspect that the manufacturers are both illiterate and possibly using a case from an older laser model to house their new model. Just a guess though.

My sighting rings appear to work fine although you need to loosen the mechanism with an allen key first (included in the box) to prevent drifting.

You can see where the Allen key fits on three of the segment in this picture (below):


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## killforfood (Jul 8, 2007)

Nero design,
That appears to be a better sighting system then the one I posted above.
I've been hanging out over at AR15.com reading a 5 page thread about this very subject.

http://www.ar15.com/forums/topic.html?b=3&f=20&t=323371&page=1

I pulled the following quote from that thread and it really describes why these lasers are such a crap shoot.

"When dealing with laser, only one or two companies may make the actual body, the other manufacturers will produce and install the module / sighting / cam system. I have been purchasing these for over a year (14 units from different distributers, manufactures, and vendors - THEY LOOK THE SAME. Module and cam design will be the difference. Please understand one thing about China manufacturers, I can purchase any product for what every price I want to pay. What this means is I can purchase a $50, $100, 0r $200 laser from the same manufacturer. The difference in price will reflect the quality that goes into the unit not what the unit will look like. Photos will not tell any difference in the produce"


I think the key is finding good solid reviews from people who take the time to mount the laser on a firearm and do some thorough testing.
How easy is it to adjust the aim?
Does the laser hold zero under repeated recoil?
Can it even withstand heavy recoil?
Does it have an IR filter?

Well I'm off with the family to go camping at the beach for a week.
See ya.


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## AJ_Dual (Jul 19, 2007)

I think the profusion of inexpensive green weaponsight lasers is that in the Asian market, there's very little private gun ownership as compared to the U.S., and very few of those privately owned firearms would be "tactical" in nature to have rail mounts, or any desire or need for a laser.

So probably 99% of them are destined for the Airsoft market. And the great distance, and language barrier between China and any gun owners in the U.S. is such that I doubt quality feedback to the manufacturers to withstand real firearm recoil happens.

One saving grace is that many Americans who are dudding up a tactical rifle with such accessories are doing it to AR-15 types with lower than average recoil due to it's direct gas impingment action, and the generous buffer spring in the stock.

But it does look good. And for $58, I'd take a chance on it. It's not a bad price just for a 20mw pointer! And I've got an Airsoft P90 it can find a home on if I think it's quality wouldn't be suitable for firearm use. 

The visible green beam could be a great benifit in reflexive aming at fleeting targets like pest control, but I sure wouldn't want one in a real defensive situation unless it was daytime. (a red and a green side-by- side for day/night use would be ideal) Otherwise that green beam is a visible line right back to you, and about as good at designating your position as the intended targets.

Bunnies, okay.

Bad guys with weapons of their own. Not okay.


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## Juicespeare1 (Jan 12, 2008)

Where did you buy that one. I don't do Ebay, so a source in the US would be great.




nero_design said:


> Looks a lot like the one I recently purchased online on EBay. It's true output is 30mW but it states on the front of the aperture casing (erroneously, I might add) that the laser is a 20mW Class IIIa 650nm laser but instead is actually a 30mW Class IIIB 532nm laser. I can only suspect that the manufacturers are both illiterate and possibly using a case from an older laser model to house their new model. Just a guess though.
> 
> My sighting rings appear to work fine although you need to loosen the mechanism with an allen key first (included in the box) to prevent drifting.
> 
> You can see where the Allen key fits on three of the segment in this picture (below):


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## happydog (Jan 14, 2008)

Hello , I am a small gun laser dealer, as in just me , But I do know about the laser you ask about, I have purchased 4 ,all four are in my parts box broke , you can buy the china stuff and get buy sometimes but thats not the one , it looks cool , but the small springs will pop off there props , the four small allen screws are never uniform to each other and will strip very easy because of alum, you can not get a replace remote , and I will stop here but most of all the lasers lite goes bad , I speak only the truth , If you already bought yours I do have some parts , but the ones you may need are broke.


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## Juicespeare1 (Jan 15, 2008)

Thx for the reply.

I bought a Lasermax UNI-GREEN but want another green laser to play with.

I haven't bought one yet but have been looking at the NCstar one and one like this. So the laser modules on yours don't work anymore?

Now that sux. I know the floating head design sux, and want one of these to play with. I have my eyes on a 20mw laser module (actual green output after IR filters) from a reputable dealer. I'd like to experiment on the actual body to see if I can fashion something myself. Maybe use the body and a new quality green laser module. I was thinking of making a metal sleeve to mount the laser module in and threading it so that when using quality screws it would be more secure.

I know the laser modules inthese are poor at best, hence the desire to get a quality 20mw laser module from somewhere else.

Would you like to get rid of your parts?


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