I'm looking for a high power, 300mA (preferably more) Led, in a 5mm package (or equivalent size) in a 10 to 20deg beam size. Can't seem to find a source.

Thanks!

 

5mm as in T1-3/4 round? I found a green one but it isn't very bright at 900 mcd

 

probably. Basically the standard radio shack size. Or what you see in cheap led flashlights.

 

May as well start here. 5 mm, commonly known as the T1-3/4 size, is the one you see most often.

Just apply some filters bit by bit to narrow your choices down:
http://www.mouser.com/Optoelectronics/LED-Indication/Standard-LED-Through-Hole/_/N-75pv5/

 

There is always laser diodes.

 

You buy the LED.. Then you buy the optics. The optics are what gives you a narrow beam.. Typically LEDs are anywhere from 60 to 150 deg viewing angles.

And by 5mm I assume you don't mean a T1-3/4 LED as I highly doubt there is one with a If of 300mA (most are only 20mA).. Now a 5x5mm is a different story.

I have seen some 20mA 5mm (T1-3/4) LED's with a 12 to 20 deg viewing angle but never a high power led that can do that without the optics.

 

You can buy them, they just aren't consistent. I used something similar for a ping pong ball liquid detector. The bulbs obsoleted on me, and they were always getting silvered on the inside. So I upgraded to LEDs.