View Full Version : PTR91 Grenade Ring now installed!

Herr Walther
September 21, 2017, 13:32
Thanks to Mark at Arizona Response Systems my PTR91 is one step closer to looking like an authentic HK G3 rifle.

I sent Mark a grenade ring extension that I purchased from Robert with the dimensions of the barrel journal and the amount needed to be removed from the inside of the grenade ring to get it to fit over the muzzle and the barrel journal ahead of the three ring sight base.

I got it today and it fit perfectly. There was only the slightest amount of friction between the barrel journal and the grenade ring. Mark did an excellent job for me on this and even Parkerized the part.

I used a minimal amount of long-setting JB Weld to attach it to the barrel journal and the front of the sight base. It looks great and it looks more authentic now.

Thanks Mark!



September 21, 2017, 19:16
Wow. Just when I thought things couldn't get any more awesome. I will have to get a couple of these.

Herr Walther
September 21, 2017, 19:22
Here is the 'before':


October 05, 2017, 14:51

Since I have a PTR and dummy rifle grenades...


October 18, 2017, 21:41
Man that looks awesome! Just wonder if the JBWELD will hold up to the heat. Generally epoxies turn to water when heated.
Is the originol an interference fit? Seems like they get it to within a .001 and use heat and thermal expansion to set the part. They heat the od part to expand, then cool the id part to contract. Then the parts slide together. Once they return to room temp, they are on there.
Not sure this type can ever be disassembled because it would be tough to cool the barrel whilst heating the ring. Maybe more knoledgable types can pipe up here.