There are a number of reasons why the P7 was not successful in the American defensive pistol marketplace. Among them are:If you're looking for an excellent, extremely safe chambered carry gun, check out the H&K P7. Safe to carry with a round in chamber because it is impossible to fire unless you give the squeeze cocking lever a very conscious squeeze.
1. With the P7 and its sqeeze lever front strap, you are either loosely gripping an uncocked pistol, or tightly gripping a cocked one. There is no such thing as tightly gripping an uncocked P7. Gripping it loosely leaves it vulnerable to being separated from you in gun grab / struggle / fall. Gripping it tightly enough to hold the lever in is tiring over time, and leaves you with a weapon in the same condition as a cocked 1911 with the safety off - which is the situation the squeeze lever was designed to fix but doesn't.
2. If you're not REAL careful about keeping your finger out of the P7's trigger guard until the gun is aligned with a target you've made a decision to fire on, you're vulnerable to an ND. This is very easy to do during the draw stroke. (Think about how you would bring the pistol out of the holster in a firm firing grip without putting pressure on the front strap.)
One of the largest police agencies that ever adopted this pistol experienced a number of these ND's (self shootings to the leg, buttock, or foot on the holster wear side) during their transitional training process.
3.If you encounter a sudden noise, loss of balance, or other surprise situation, or need to grab something tightly with your nongun hand, you are extremely likely to encounter either the startle response which causes the hands to automatically and unconsciously clench with about 50 lbs of force, or the parasympathetic nerve response which causes the opposite hand to grip tightly when the other hand does so. Either response will cock the weapon involuntarily and leave it in a condition functionally identical to a cocked 1911 with the safety off, and will give away your position as described below.
4. The cocking mechanism is LOUD. Each time the squeeze lever is either gripped or released, there is a pronounced "CLACK!" that may not be noteworthy on the range, but in a tactical situation where you'd like to keep your opponent from identifying your position whenever you can, that inescapable noise is a dead giveaway of where you are. It has about the same effect as shining a flashlight on yourself. It's an unnecessary tactical gift to the opponent that I see no reason to give.
To sum it up, the P7 never made it in the marketplace because it was an imaginative solution to a problem that is better resolved by proper training on any one of a number of high quality weapons, and the new solution brought with it a suit of new problems that was judged to be unacceptable by the law enforcement community as well as the general shooting public.
The XD is available in a 16+1 .40 S&W configuration as the XDM. Grip size is the same as the earlier XD. Right now it's only available in the full size configuration (grip size same as the XD with an extra half inch on its match grade barrel) which would make a great uniformed carry or home defense piece. Details can be found at the link to the Springfield Armory catalog below. Descriptions of the XDM start on page 18.XD's are nice but there are pistols out there that have more capacity with relatively the same dimensions. I.E. FNP-40 is close in size to an XDSC 40. FNP-40 has 14+1, XDSC has 9+1 and 12+1 if you use the extended grip.
http://www.the-m-factor.com/images/down ... atalog.pdf