Summary:
After about 1,500 rounds, the rifle is very fun. I find that after about 400 ~ 500 rounds, the HK will need some level of cleaning due to fouling from the 22LR ammunition (which is very dirty). You will need to spray it down with a cleaner/lubricant otherwise, the rifle will start feed jamming or in some cases fail to extract resulting in a double feed. A double feed in this rifle is a Major PITA since you can't easily hold the bolt open.
Double Feed Clearing on this rifle is done by removing the magazine. Using your free hand, pull the charging handle, insert finger up the mag well and pushing up on the bolt hold open catch and then clearing what doesn't fall out and if needed, pry out the stuck round in the chamber.
I suggest bringing a armorer's multi-tool with you to get these rounds out. A paper clip also works but much less efficient.
Anyway, in closing. This is one of my favorite rifles and it shoots extremely tight groups. I will post targets up from my next outing (which I hope is soon).
Here are a few close ups of the rifle.
Bolt and Bolt Cover
Rear Receiver with Magpul ASAP Sling Mount. Forward Assist is fake and functions but doesn't advance the bolt,
HK Rail with Magpul AFG 1
Gas Block - Non functional. This HK is direct blow back operation.
Top down view of the lower receiver - hammer and trigger group insert.
Upper receiver - bolt carrier, return spring. These are typically non-removable. Cleaning is made extra difficult due to the small spaces and dirty 22LR ammunition.
View past the flash hider to show the barrel and barrel sleeve. This is a non-tensioned barrel unlike the UMAREX Colt M4 which is tensioned. You can dis-assemble the rifle without taking off or loosening the flash hider.
Upper and lower receiver together. Bolt release is fake, does not function. In this image, you can see the bolt hold open mechanism and this is triggered by the custom follower in the HK's magazine. The magazine is completely NON-standard. I am working on ripping a UMAREX magazine apart and inserting it into a Magpul PMag magazine body. We'll see how this works.
Upper receiver detail. You can see the mechanism that works with the magazine to hold the bolt open on the last round.
