I tell you what, I had a small 23g pin nailer but could only handle short pins, worked great but for pins with longer length I went with this and am more than happy, I put it to the test with Padauk hard wood and that stuff is a close second to dam near concrete as far as hardwoods go. They are not cheap however the design and power is explained the first time you try it. the 650l which I have also has a lock out at about 8 pins left. Nice feature to have the gun actually lock to tell you your almost out of pins, a lever lets you shoot out the last few knowing you only have a couple left so no dry shots.
I agree 100% on this quick review:
"Just one more example of getting what you pay for. I hesitated a long while to shell out this much money on a headless pinner, but after reading so many glowing reviews in so many different publications, I splurged and ordered the Grex P650L. Now, more than a year later, I have fired countless thousands of pins through it, ranging from a mere 5/8" to 1-3/4" in length without even one singe failure to feed. I also like the fact that the gun "locks-out" when empty and won't fire. I've had so many other finish nailers just punch away, thinking I'm firing nails when they are actually empty. Saves a lot of time. Lastly, the 23 gauge is awesome. It leaves an almost indistinguishable hole which is almost always just lost in the wood grain and can't be seen unless really looking for them. On paint grade pieces, the paint usually bridges the hole without any filling what so ever. Truly a flawless gun."