In the last blog post, I talked about the specifications and ordering the PTR PDWR. Even before it arrived, I knew I wanted to add a brace. My plan was to use PTR railed handguard and I had a “wait and see” attitude towards the brake.
So, the first step was to remove the existing end cap. In HK-type weapons is is held in place by two push pins that are simply pushed back out. You’ll notice that one side is relatively flat:
The other side will be protruding and this is the side that you push on and will remove the pins from the other side:
You then wiggle the end cap and push it off the end of the stamped receiver. It will look like this:
I then secure the end cap assembly in a vise to make working on it easier.
In the next photo you can see how the tube and sling really are like a small stub of an AR/M4 buffer tube complete with an indexed end plate to keep it from rotating and a castle nut. The swivel is separate from the tube and is threaded into place so unscrew and remove it first.
In the next photo, you can see the lighter grey castle nut on the black tube. The light grey surface you can see in the otherwise black cap is the plate you will need to fish out after you back off the castle nut.
To remove the tube itself, you do the exact something you would on an AR. Use a castle nut wrench to loosen the castle nut and then thread it back out of the way. Then pull the end plate out of the receiver so it can rotate and then turn the tube to remove the assembly.
In the next photo you see the castle nut wrench on the tube with the sling. I realized shortly after this was taken that I probably needed to get the sling off before I could back out the tube – that is why I said remove the sling first.
As written above, you will need to pull the end plate out of receiver to be able to turn the tube. With the plate pulled out from the receiver, the tube simple unscrews. If it does not want to unscrew, make sure your plate is out of the way. Also in the next photo, you can see the very secure mount that the sling screw threaded into. That was well thought out.
Now it is a matter of reassembly. I installed an SB PDW tube and an SB SOB (love that acronym) brace. Now, to install the tube, I reused the PDWR’s end plate to and a new castle nut that came with the tube.
To install the buffer brace on the tube, I spray silicone on the tube so it can slide on way easier plus it makes it easier to true up the brace if it needs to move a little bit one way or the other.
Here is the end result with the tube on the end cap assembly.
Now, in terms of the handguard, I thought I was going to use the original PTR model you see in the photos above. It’s a little small left-to right in my hands so I actually wound up changing to a US made wide tropical forearm. It’s a tad looser than I would care for and will post updates about that later. I may stick with the existing wide tropical unit or move to a DTAC like I have on my POF-5.
So that is it for now. The next post will be about the scope I mounted.
If you find this post useful, please either buy something using one of the links to eBay and Amazon or click one of the AdNow advertisements. EBay and Amazon you need to buy something, AdNow pays for each link you visit – no purchase needed. With Amazon, if you click on one of our links and then buy something else – even unrelated stuff like clothes, electronics and groceries – we get credit and it would be hugely appreciated. Doing something like the above will help us fund continued development of the blog.