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Targeting laser advice needed

DrumFed50

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Hello,
I've experimented with lasers on and off for 18 years, back then, they where CO2 gas.
I need advice for my next purchase.
A laser the cuts or burns is well and fine and power is always useful.
But I am looking to upgrade my laser sighting equipment for my .50 Beowulf
M4 rifle. I currently have a Laserlyte K-15 on it which claims a <5mw output @532nm. I wish to replace the laser module inside with a more powerful one that I can see at long range during bright sunlight hours. Its divergences is also not so good. No info on this is listed but at 150 feet the dot is
roughly 2-3 inches in diameter. I would like something with a divergence of around 1/4 " or smaller at 100 yards. The K-15 internal laser modules diameter is 0.45 " and its length is 1.45". The driver board and spring contact attached to the rear of the module adds another 0.96" to its length. I'm looking for quality and power
This has to handle recoil from high caliber weapons. It needs to be a clean beam ie glass optics not plastic.
On ebay they have many 532nm laser modules listed.
at 5,10,30 ,50,100,150,200 mw.
How can I tell if they are selling what they advertise? power rating, glass optics, QC, divergence.
Any suggestions on distibutors?
I'd prefer to stay below $100, as this is not for burning, but visibility at long range is needed. Also, the module needs to be te same size range.
I'd prefer expert answers only.
Thank you gentlemen
Sincerely
Les
 

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Achieving the power is not the issue, but getting the divergence you seek may be...

Getting a 1/4in dot at 100yards will be tricky with low cost modules.
While the optics they use are okay, to get a tight beam like that would
require a really good expander set, if not a secondary set of optics to expand the beam further and get the divergence even lower.

Im not sure how easy of a task this would be if price is of concern. I also make green lasers from scratch, but its been a while, and cant remember how good I was able to get the divergence at the specified range..

Hope this helps some.
 

Asherz

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Well according to the info you gave, assuming at 1ft, your laser has a beam diameter of around 1-2mm, and at 150feet its 3", it gives you around 1.6 mrad divergence, that's not fantastic but it's respectable.

The best divergance you'll be looking at without a beam expander would be around 1.1mrad, it is possible to get it alot lower with a beam expander, but they are large heavy and not practicable for use on a gun. With 1mrad you'd be looking at around a 1" dot.

Power wise, I would suggest around 100mW, since the distance is fairly great and you'd be surprised how even the brightest green lasers get drowned out in sunlight.

Stay away from ebay when dealing with green laser modules, they're almost always underspec.

As for the mount, the standard size for most green modules we deal with is 12mm, so if you measure your current module and it's 12mm diameter, you could do a direct replacement as long as you can give the module around 4V of power.

Some good sites that produce some quality products and good prices are:

rayfoss.com
o-like.com

they're the chinese company's we deal with a lot and often product over spec modules with good quality QC.

I'm not 100% sure on this but one of the best quality companys around for hobby use is CNI, Scopeguy (Glenn) runs one of the largest groupbuys on the forum for this company and gets some pretty good deals, although I'm not sure whether they do only green modules. The cost will be quite a bit more as well compared to the sites listen above.

And unfortunately green lasers do deal with some sensitive optics, lookup DPSS system. The only away to avoid that is dish out thousands of dollars for an unreleased green diode, at around a few mW. Not practicable, stick with the modules I think it should stand up fine, especially since you'r using one currently.

Hope this helps :)
 

DrumFed50

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Thank you gentlemen for you thorough and quick replies.
I measures the module again in metric and it is 11.5 mm diameter. The housing it fits in has ample room for 12mm modules. I could definently live with 1 " at 100 yards.
it would be far better then what I have. I did not realize that divergence was normally this bad. I will research the options you gave me and stay clear of ebay.
Thank you again.
 
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snypr

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^ major factor will be recoil. I purchased a 532(10mw) with mount for my 12ga home defense gun. After spending $200.00 on it (about 2 years ago and on a no name brand), the laser diode self destructed from the recoil of the gun (after 3 shots), shooting low base bird shot (very low recoil). Viridian makes a nice unit (5xl) if memory serves, but you will have to check the specs on the diode.
 




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