This discussion pops up from time to time, and yes, there are some jurisdictions that require full head nails, but if you read the actual studies, there is no factual basis that a full head nail "holds" better then a clipped head.
From a previous post:
From Senco:
(you guys will love this)
Q: What are the pros and cons of clipped head and full round head nails?
A: The clipped vs. full round head (FRH) nail question:
1) Clip heads were the original type of collated nail for air tools, and still remains popular in most parts of the USA.
2) FRH nails came on the scene in the late ’80s as a popular product in the earthquake/hurricane markets (SoCal-Fla). In these markets, discussions about possible code changes led many builders to change from the clip head to the FRH nail. Building inspectors started to discriminate against the use of the clipped head nail. They felt the FRH would help prevent an overdrive into shear wall (structural sheathing).
3) Today, it seems the FRH nails are the dominant format on the West Coast, Florida and the South Atlantic regions. Again, FRH is the product of choice in the earthquake and hurricane prone markets.
4) Independent lab research results yield no significant difference in performance between both types.
5) FRH nails come in strip or coil format. The FRH strips are collated with a plastic material; the coils are collated with wire. Clipped head nails are only available in a strip format and are collated with paper strips and adhesive. The FRH strips will leave some plastic debris on your job site, and some plastic chunks embedded into your work surface trapped by the nail head (flagging). The paper-collated clipped heads are a bit cleaner, with some flagging, but most of the paper seems to disappear.
6) The clipped head tools have a shorter magazine track because the nails are right next to each other. The FRH tools feature a longer magazine track, which protrudes to the rear of the tool body. Some users prefer the shorter magazines for the maneuverability they offer, and some users like the longer magazine tools for the exceptional balance.
Our advice: Buy the format that is popular in your market, so it’s easy to buy the nails where and when you need them. Our dealers tend to stock only the popular format for the specific market you are in, so if you buck the trend, you might have difficulties finding the nails designed for your tool.