Modifying and Accessorizing the FN303


One of the problems I have encountered with the FN303 is that air line is prone to getting kinked which will eventually cause it to develop a leak.  In my estimation this is a design problem as the line sticks out at  90 degree angle from the side of the launcher which causes unecessary stress when in use and is prone to being bent when stowed in the soft carry case.  Later versions of the FN303 “operating system” feature and angled hose assembly which presumably alleviates these issues.  But what about those of us who are have older launchers and are not blessed by FN to buy restricted parts?

In my searching for suitable projectiles on I ran across what is being sold as a stainless steel 45 degree elbow for $6.  Now underneath it may be stainless steel but it looks like chrome plated crap.  The threads were buggered up with flakey cheap chrome plating and required careful scraping to get it to screw together with other parts.  It’s also a bit bulky and will not fit through the hole in the side of the FN303s plastic clamshell “stock” which allows for disassembly.  Rather than cutting the hole larger I chose to simply screw the elbow on with the right side of the clamshell in place.  This will complicate disassembly of the launcher at a later time but it looks more or less ok.  The bigger issue is that the crappy chrome plating is easily scraped off and cosmetically it looks even shittier from the wrench I used to tighten it on.  On the plus side it holds pressure just fine and the hose position seems much improved.  On the whole though I would not recommend this item.

What I would recommend is the beautiful little Parker 316 stainless 45 degree elbow that is available on Amazon for $32.50.  It’s a bit pricy but what you get is a high quality aesthetically pleasing fitting that works much better with the FN303 in that it fits with the plastic clamshell.  It’s rated for 5,500 PSI and there is a plethora of information on the various specifications it meets which is a refreshing change from many of these sort of items which are of murky quality.  Unfortunately it’s very slightly too large to fit through the plastic clamshell but unlike the other angle piece this one requires only very slight enlargement of the hole to fit through right side of the clamshell.

The iron sights on the FN303 are shit.  Yes, they are sufficient to hit a human sized target at close range but they are not particularly quick to use and, despite what it might say in the manual, cannot be adjusted in any way that I can determine.  There is an Eotech variant that was developed specifically for the FN303 with a fancy drop compensation reticle however I’m not quite ready to drop $450 for one.  Bushnell TRS-25 to the rescue…. Yes, it’s a cheap little red dot and I’m normally averse to this sort of thing but in my experience it’s an excellent value.  It has great battery life and I have been very satisfied with the TRS-25 as a budget red dot to go with my cheap ass Palmetto State ARs.  The TRS-25 linked to at the bottom of this page is the variant with a built in riser, if you buy the other version you will need to buy a riser of some sort as shown in my picture here.

A final accessory I will mention for now are packs of port fill covers.  It was amazing the amount of crud I found in both the tanks and operating system of my FN303s that can only be explained by sand getting into fill port and then worked through when the tank was filled.  I’m not sure how FN missed the opportunity to sell these with a little FN logo for $7 each but generic covers are readily available on Amazon and other sites for less than $1 each.

Parker elbow for $32.50:

MCUS elbow for $6:

1/8 Inch 45 Degree Elbow

Bushnell TRS-25

Fill port covers


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