With very few exceptions, the Bosch FNA250-15 Angled Finish Nailer is among the most nimble and lightweight finish nailers we’ve ever used. Features like a tool-less trigger mode and adjustable depth of drive make this a tool that matches flexibility with quality construction. It’s just easy to manipulate into tight areas and that makes it a very effective tool for finish nail applications. We brought it with us to several trim-heavy job sites. It remained consistently equal to or superior to many other products we’ve used.
We interviewed several pros and let them handle and use the 15-gauge Bosch FNA250-15 Finish Nailer. Reactions varied, but many shared similar traits – the tool was perceived as lightweight, slim, and easy to adjust. Though we never encountered any jams, the nose easily disassembles. Users like when any difficulties can be easily dealt with.
Full Force Technology
According to Bosch, the company has been working, in some fashion or another, on the Full Force design for around 4 years. Full Force technology uses a patented air chamber design. It eliminates the need to use some of the drawn air to recycle the driver to the start position. Basically, it sends a second, smaller, burst of air through the gun. This resets the driver—removing the need for a surrounding chamber to store air. The result is a 20 percent space savings (mostly in girth) and a 10 percent power boost over comparable tools. The power-to-size ratio is actually quite impressive – and anyone who picks up the nailers sees this right away.
A typical pneumatic nailer 
Full Force Technology
Bosch FNA250-15 15 ga Angled Finish Nailer Features
Build Quality
We love the look of the Bosch Full Force nailers. The FNA250-15 impressed us no less than the impressive SN350-20F framing nailer. It’s just as attractive, though the FNA250-15 vents out the rear of the tool instead of the front. The vent can be pointed in any direction. You’ll want to ensure it’s moving the ejected air away from your face. The colors are the expected Bosch blue with an aluminum casing. Ample rubber overmold that protects the handle and offers a secure grip that works perfectly with or without gloved hands.
Like Bosch’s SN350-20F framing nailer we reviewed earlier, the trigger also has a nice rubber overmold. It fit our gloved hands without any trouble. The tool features a duck-bill bottom that helps keep your finger ready to press the trigger—even when you hold the tool overhead or sideways. One of our favorite features was the tool-less mode change. You go from sequential “one pull, one hit” to the popular “bump mode”. Holding the trigger down readies the tool for continuous shooting on impact. Switching modes is about as easy as you get. You simply push in on the yellow plastic insert located on the backside of the trigger and move it up or down to switch modes. We loved being able to flip modes so easily, though we typically left it in the normal mode. Bump mode is extremely effective for framing applications where precision isn’t as important.
Loading the Magazine and Clearing Jams
We selected the Angled FNA250-15, which pitches the magazine at approximately 34 degrees. It gives you the ability to really reach into tight spaces like corners and alcoves. Nails are loaded by feeding them through the back of the magazine. You then pull back on the nail feeder mechanism which rides over the nails and then settles in behind. Jams can be eliminated quickly by simply flipping up the Quick Clear mechanism’s hinge. We practiced the procedure and found it to be very quick and easy, though we never actually needed to do this during the course of testing the tool.
Adjusting Nailer Depth
Like the SN350-20F Framing Nailer, you can easily adjust the nail depth by spinning the metallic red depth adjustment knob. Located just behind where the nail leaves the tool, this control keeps you from having to vary the air pressure from the compressor or grab a tool in order to set the nail depth. We found ourselves using this feature periodically when switching between paint-grade woods and hardwood. Even with gloved hands, we found the depth adjustment control easy to use.
Unlike Bosch’s framing nailer, the depth control doesn’t have any visual marks to use as a guide. You can actually over-adjust the tip until it falls out! Of course, if this happens it just screws back in place. The tip also comes with two removable no-mar rubber covers. You can store one on the magazine itself, so it’s always handy.
In the Field
The Bosch FNA250-15 15 ga angled finish nailer was a very consistent tool, sinking both 2″ and 2-1/2″ finish nails just below the surface of the wood in our door trim project. We used Porter Cable, Paslode, and even Senco brand 15 gauge fasteners in the nailer and didn’t seem to find anything that caused a problem. Air was supplied by the excellent Bosch CET4-20W 4-gallon compressor.
Putting up trim around an antique panel door involved firing into some old (read: nearly petrified) 2×4 lumber (the 80-year-old kind that actually measures 2″ x 4″). We’ve seen regular trim nails bend on occasion when hammered in by hand, but the Bosch consistently drove in our fasteners without breaking a sweat. We found that we had to adjust the depth to a bit higher than we were used to, but the tool came through.
The finish nailer also came in handy with some flooring work we did, including the installation of some interior pine thresholds. We kept the no-mar cover off of the tool for the most part, and found the uncovered tip to be easy to use without damaging the surrounding wood. For those working on more delicate materials, it’s easy enough to install as needed.
Conclusions & Recommendations
We found that you can get a lot accomplished with the Bosch FNA250-15 15 ga Angled Finish Nailer. This is the highest compliment for a tool that gets itself out of the way and lets you accomplish your work. The retail price of this tool is borderline astronomical, however, street prices were commonly between $100 – $150 lower than the list, putting it right in line with the higher-end competition. For this reason, we feel it represents a good value. The performance was exceptional, and the Bosch FNA250-15 15 ga Angled Finish Nailer earned our respect.
I have one of these and never use it. I can’t find anywhere to buy nails for it. It takes a different angle of nails than other trim guns, but it doesn’t say on the gun what the angle is. I can’t find that information in the owner’s manual either. Wish I’d never bought it.