One of the benefits of having a long standing advertising relationship with Brownells is having access to catalog data as well as a deep familiarization with their product offerings. When researching updated website content for .22 pistol conversions I happened upon the HK HK P7K3 22LR kit. Now if you happened to click the link to the left you too will probably be taken back by the price tag of the kit. While I am quite familiar with the HK P7 the HK P7K3 22LR variation was unknown to me. I did a little research and found hkp7.com had the info that filled in the missing pieces. It turns out that while Brownells is offering a .22 conversion kit the HK P7K3 was originally a HK P7 designed to shoot three calibers .22 LR, .32 ACP, .380 ACP. Today these pistols complete with caliber conversions are selling in the $3500-$5000 range. At those prices I will never own one but as most know, money is know object if your a true HK fan .
Download the HK P7K3 Users Manual (English)
Anyhow according to the author at the site mentioned above the additional slide is only used when converting to .22lr.
HK P7K3 22LR