I recently acquired this Umarex H&K 416 pistol. For only $299 from CDNN, it is a bargain for a Pistol AR in 22LR. Originally the HK416 pistol comes with a faux suppressor muzzle device and a rear end cap on the lower receiver that has a QD sling fitting.Aside from the faux suppressor, a lot of the AR style features are not real AR accessories. The trigger is built into a drop in pack so unfortunately it does not use standard AR triggers. The safety selector is proprietary as well. The forward assist and bolt catch/release are also fake but the dust cover is functional.
The faux suppressor is threaded onto an uncommon thread pitch. However, HKPARTS.net makes a threaded adapter. I got one so I could install my Spectre II suppressor.
The next upgrade was to install some sort of brace/cheek rest. The Umarex HK416 lower receiver is not like a traditional AR receiver. It is similar to the VFC airsoft gun HK416 receiver. Here is a photo from the back of the .22LR receiver. Below is a photo I found of the VFC receiver.
I thought it suspect when I saw that Umarex sells airsoft guns of the HK416. Particularly the HK416C which VFC also happens to make and sell. So I ordered a HK416C stock and modified it as a brace and can’t be shouldered. It installed without any modification. With the brace collapsed, it works rather well as a cheek rest.
The final upgrade was to ditch the cheese grater quad rail. I looked into various rails and settled on the Midwest Industries HK416 9″ rail. It covers some of the suppressor but allows enough room to remove the suppressor. The MI rail installed rather easily. It was a simple matter of unscrewing the cross bolt in the Umarex rail, sliding off the rail and sliding the MI rail over the factory barrel nut. It is a perfect fit. Now I have a slightly longer sight radius, the handguard is smoother and narrower. It is MLOK so I can install rails if I need them. The HK416 pistol does not have a faux gas block/front sight like the rifle version. If it did, I would have to cut the sling loops off the gas block.
I also modified a spare AR grip and swapped out the HK416 style pistol grip.
The HK416 pistol works great. I did experience a little gas blow back when cheeking the pistol close to my face and rapid firing. If I use the brace then I do not experience that problem. For $299 plus the minor upgrades, I am very satisfied with this setup for the cost. This has turned out to be a very fun plinker.