Tuning FX Maverick Locking Shroud Mod (For Barrel Rigidity & Harmonics)

[mtnGhost]

Figured that this would be worth it's own thread. I've had some ideas for improving the barrel support in the FX Maverick since they were released. I haven't had the time or drive to make the more complicated idea, but I went ahead and took a risk today by doing a permanent modification to my rifle so I could test the simpler idea. I've warped my fair share of FX barrel housings, but there's no bending this one lol

First, I made a crazy carbon fiber shroud with titanium end caps (aluminum would also work for this though). Thread link with the details - https://www.airgunnation.com/topic/anyone-interest-in-heat-anodized-titanium-parts-fx-maverick/#post-1190170

Then, I counterbored the front support housing to ~19mm as well as the rear end cap that had already machined (too lazy to make a new one)..

Then I made a bushing with a perfect 14mm press fit for the barrel bore and press fit for both the end cap and barrel support housing counterbores..

So when I thread the shroud on to the barrel, it tensions down just enough to make the barrel rock solid to the rifle. They literally become one solid piece when everything is connected. Here's a short video clip that I uploaded earlier to IG..


https://www.instagram.com/tv/CZ0Y9Z2qlmw/

Overall, great success!

 

[Vetmx]

Very interesting note on over tensioning. Your system is so rigid that you get more for less. Very nice. They say measure twice, cut once. Sometimes it’s best to put off a project long enough that the best way of going about it rises to the surface after all the thoughts are done bouncing around in our heads. Occasionally when we jump right in we wind up with several revisions. I am curious what symptoms arose when you stretched some liner housings. That’s valuable info as I’m a die hard tensioner with these spaghetti noodles.

 

[mtnGhost]

Very interesting note on over tensioning. Your . I am curious what symptoms arose when you stretched some liner housings. That’s valuable info as I’m a die hard tensioner with these spaghetti noodles.

Oddly enough, I've somehow managed to warp the FX barrels and a 700mm CZ barrel while they were in one of my weakly padded nylon rifles cases (a thinner 5.11 bag). Probably from getting banged around in my vehicle in the mountains. Bent a couple of others in the field.

The only 500mm FX housing that I trashed was the original 500mm housing that came with this Mav. And that was when I was reinstalling my factory scope rail after I rolled up to Kraford & Lypt's machine shop to help Stephen test fit the first Gigarail prototype. He's using 12mm M3 screws for his rails, and I didn't realize that 12mm was long enough to bottom out deep into the barrel! Thank God my liner was alright!!! LOL

 

[biohazardman]

Another very nice mod for sure. Looks to be very good for keeping things concentric around the bore which is something I am always concerned with on my Impacts when I do my simple barrel tensioning mod. I am also concerned with over tensioning.

 

[mtnGhost]

Another very nice mod for sure. Looks to be very good for keeping things concentric around the bore which is something I am always concerned with on my Impacts when I do my simple barrel tensioning mod. I am also concerned with over tensioning.

Thanks. Yeah it's definitely better to add minimal tension, and to get the threads to just bottom out in the right place. Alignment mods for concentricity are ideal for tensioning solid barrels (you really don't want any micro moment / play)!

 

[mtnGhost]

I did one final round of modifications. Re-added / re-located the o-ring groove in the support housing and I made another base ring (with an o-ring groove as well). The reason for doing this - I noticed that I was having POI shifts of up to 3" at 100y, depending on how much torque was applied to the shroud. My overall goal was being able to torque it down tight enough to make the shroud very stiff (and without any lateral barrel movement), so I adjusted the design a bit and hit the tighter tolerances all around.

So I solved for this by adjusting the ring and end cap specs and I'm now running a little 19x1mm o-ring now in the back of the end cap that bottoms out on the ring. The effect of this o-ring is AWESOME! It actually provides a "feel" for how much torque is being applied to the shroud. It's soft and smooth as it compresses, and then there's a point where it stops (so any further tightening / torquing effort gets a lot harder). This seems to provide VERY repeatable torque!

Posted some video on IG of the process and the fit of the ring in the end cap - https://www.instagram.com/p/CZ96t5oLMdm/

The POI shift appears to be non-existent now, but this is a MUCH better design change.

Last little mod is this titanium shroud extension. It's a pretty solid hunk of metal, but there's no POI shifts with or without it

 

[bunkeru2k]

Would it be conceivable that you could mill a wrench flat on it somewhere so you could use a torque wrench to get exact torque measurements for repeatability?

 

[mtnGhost]

Would it be conceivable that you could mill a wrench flat on it somewhere so you could use a torque wrench to get exact torque measurements for repeatability?

Yep, using a 1/2-20 hex nut on the endcap thread or shroud extension thread + socket on a torque wrench.