Gravitas - Sentry Raw Copper

The Copper Sentry is one of the heaviest pens on the market. However, I find that hand fatigue is hastened more by grip section than the pen's overall weight. Moreover, the pen is back-weighted, with the center of gravity resting on the web of your hand between thumb and index finger, which makes the business end of the pen much easier to move across the page. The grip section of the pen is made from PVD coated stainless steel, and tapers from around 13mm to 11.5mm in diameter, making it ideal for a large pen.
The finish is flawless and free of blemishes and tarnish, but it will accumulate micro-scratches over time. However, unlike coated or painted pens, these scratches will me much less noticeable, because there is no bright shiny metal to contrast with the colored coating.
The nib is JoWo #6 compatible, meaning that the nib unit has the same type and size of threads as a standard JoWo nib unit, and you can most likely put a different type of JoWo #6 type nib into the nib unit. However, if you do that, be extremely cautious when putting the cap back on your modified pen; if the new nib sticks out a bit further than the original nib, there's a chance that the inside of the cap may touch/damage/destroy your new nib. And I can not tell the difference in performance between the Gravitas nib and a "genuine" JoWo #6 steel nib. The nib is smooth, with barely the hint of feedback, and ink flow is absolutely perfect, even with Pelikan 4001 Königsblau ink, which is dry enough to cause ink flow problems in some of my other pens.
The clip...is still not present on Gravitas fountain pens. And there is no roll-stop, either. So...that does limit your options in how you transport your pen, and the handy black single pen zippered pouch the pen is delivered in may become your default storage and carry option. If you're considering a pen sleeve, get one with a folding flap, to prevent the pen from sliding out of the sleeve.
Last item: ink capacity. Gravitas pens are designed for Standard International cartridges and converters. Converters hold 0.5ml, Standard International Short cartridges hold 0.7ml, and Standard International Long cartridges about 1.2ml - 1.4ml. You can "refill" cartridges with bottled ink using a blunt tip ink syringe, which gives you almost as much ink capacity as a standard piston filler pen. With a little practice, you can refill your cartridges without making (much of) a mess ;-), but keep a paper towel handy, just in case.