Bo's Explanation of the P7 M13 XM9
project guns:

Here is the quick and dirty explanation of some of my P7s:

HK P7 A10. US Military started looking at new pistols in the early 1980's The Trial was designated "XM9". HK made 34 examples of a 10 shot mag. model of the P7 by extending the frame, called the A10 ("A" = arbeitstitel = working title) & shipped it to the US for testing. These were taken out of current production P7s so the serial number range was 27841-27873. US wanted bigger mag. so the P7A13 came next. HK then used the same serial numbers over again that they had used on the A10. RH grip says "XM9", Left grip red "P7A13". I have 2 of these.

HK P7 "A13" #VM0036. Arl. VM=Versuchsmodell means Test Model. This one is the first prototype P7 model that works. Was shipped here for US Govt inspection/testing which is how it got away from the factory. Almost all the other VMs are still at the factory. HK made 33 P7A13 guns using the same serial numbers they had used on the A10 guns, but this is the only VM they made.

PDW (Personal Defence Weapon) US Army Trials (1984) to choose new US service weapon. XM9. TRAINING PROGRAM WEAPONS: US govt. required HK to provide 10 P7M13s to train the Trials shooters/armorers. Special serial #'d & engraved "Training Program Weapon" on slide so that they could not be substituted for the guns that were actually shot and put through all kinds of testing. These were the first "production" M13s. They were made entirely by what HK considers "hand" but are identical to regular M13s. Regular mags. work fine in TPWs. Cost HK $6,200 each.

P7M13 #015. When the P7M13 was born, the first pilot lot went from serial number 001 to 059. Actual production numbers started at 71101. This example of the pilot lot is NIB.

All of these P7s are very rare.