Questions

425 Views 14 Replies 4 Participants Last post by Mastergold2027, 33 m ago

Mastergold2027

Discussion Starter · 1 mo ago

Howdy Y'all! I'm proud new XCR-M owner, only have about 200 rounds through it so far but those rounds have been nothing short of a pleasure. I'm very impressed with the rifle and only have a few minor gripes. Charging handle knob being one but I've already drawn up prints to machine myself an "enhanced" one. But my other gripe and origin of the forthcoming questions is the FAST3 stock. I feel the buttpad is very thin and makes it pretty uncomfortable, I plan to 3d print and experiment with a different buttpad. The cheek riser is my other point of contention with the stock, I find it to be uncomfortable and perhaps larger than it needs to be.

Has anyone attempted to make parts to improve upon the FAST 2 or 3? Specifically the buttpad and cheek riser?
From what I've read on these forums, it seems to be common practice to swap out the FAST for an ACR stock or buffer tube and AR stock. From an aesthetic and features standpoint I love the FAST3 so I'm thinking I may want to attempt improvements before writing it off for a more traditional AR stock.

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roflcopters

· #2 · 1 mo ago

Not that I'm aware of. Someone sent Alex some feedback on design improvements but I'm not sure that went anywhere.

Flskunkape

· #3 · 1 mo ago

Make it, we need some more aftermarket support!

Mastergold2027

Discussion Starter · #4 · 1 mo ago

Flskunkape said:
Make it, we need some more aftermarket support!

Agreed. Not sure what I can do about the cheek rest but I have a few ideas for improving the buttpad. I'll draw some stuff up on CAD this weekend.

Mastergold2027

Discussion Starter · #5 · 1 mo ago

roflcopters said:
Not that I'm aware of. Someone sent Alex some feedback on design improvements but I'm not sure that went anywhere.

There are certainly worse and less usable stocks out there. This one doesn't need much to be very solid in my opinion.

Sean K.

· #6 · 1 mo ago

Mastergold2027 said:
Agreed. Not sure what I can do about the cheek rest but I have a few ideas for improving the buttpad. I'll draw some stuff up on CAD this weekend.

Not sure if you have the plastic pad model or the rubber one. The rubber one was far better. Not sure if you could adapt one from DoubleStar Arms or whoever it was (Ace maybe?) that was making a tube folder similar to the original design XCR stock.

Just searched....Ace apparently is DoubleStar now...

Again, not sure if one of their pads would work....

Mastergold2027

Discussion Starter · #7 · 1 mo ago

Sean K. said:
Not sure if you have the plastic pad model or the rubber one. The rubber one was far better. Not sure if you could adapt one from DoubleStar Arms or whoever it was (Ace maybe?) that was making a tube folder similar to the original design XCR stock.

Just searched....Ace apparently is DoubleStar now...

Again, not sure if one of their pads would work....

I think mine has a plastic pad, at least it doesn't feel like rubber. If the DoubleStar arms has the some hole positions as the FAST than it just might work. Not sure if I can post links here or not but if someone happens to have a DoubleStar recoil pad on hand and a pair of calipers could you measure that hole distance?

Sean K.

· #8 · 1 mo ago

Mastergold2027 said:
I think mine has a plastic pad, at least it doesn't feel like rubber. If the DoubleStar arms has the some hole positions as the FAST than it just might work. Not sure if I can post links here or not but if someone happens to have a DoubleStar recoil pad on hand and a pair of calipers could you measure that hole distance?

Keep in mind there were persistent rumors that RobArms was using Ace tube stocks on their early model rifles. However, I'm not sure that was accurate b/c Ace (to my knowledge) always used solid polymer bar stock for the top 'cheek tube' with a foam sleeve. RA used aluminum anodized tube on both the upper and lower tubes....

Supposedly, the rubber butt pads were the same size/shape/hole pattern, but I've never had my hands on an Ace to double check. Might have more luck on a dedicated AK forum where they are commonly used. Here, everyone that had the old tube folder used the RA one since it was more robust due to the aluminum upper 'cheek' tube.

Mastergold2027

Discussion Starter · #9 · 4 d ago (Edited)

Sean K. said:
Keep in mind there were persistent rumors that RobArms was using Ace tube stocks on their early model rifles. However, I'm not sure that was accurate b/c Ace (to my knowledge) always used solid polymer bar stock for the top 'cheek tube' with a foam sleeve. RA used aluminum anodized tube on both the upper and lower tubes....

Supposedly, the rubber butt pads were the same size/shape/hole pattern, but I've never had my hands on an Ace to double check. Might have more luck on a dedicated AK forum where they are commonly used. Here, everyone that had the old tube folder used the RA one since it was more robust due to the aluminum upper 'cheek' tube.

My bad for the inactivity, I think for the time being I'm going to opt for the folding buffer tube adapter. Don't worry I still want to try and make some improvements to the FAST stock but I'd like to have something that makes it tad more shootable for now. The main 2 things I want to address on the FAST 3 are the cheek riser and the buttpad. Anyone know where I can get my hands on a folding buffer tube adapter? Doesn't seem like RobArms has them anymore.

Also, I'll share some pictures of the charging handle knob "upgrade" I did.

Mastergold2027

Discussion Starter · #10 · 4 d ago

Here is the current prototype knob. Made this out of bronze, things I learned:
1. In this instance bigger is not better, made it a bit larger than the original one and ended up not being happy with it.
2. The weight/mass of the knob matters. Prior to changing the part out I had put roughly 300 rounds through the gun without any sort of malfunction or failure save for those that were the result of messing with the gas system. However, when I think the gun out with the new knob I was having a lot of issue with the bolt not going into battery when I would pull the charging handle all the way back and let go. I'm guessing that the added wait of the new knob is too heavy for the spring to force the bolt into battery. Supporting this theory IMO is that once I got the bolt into the battery the gun functioned as normal and didn't have any issues until I loaded another mag.

I have Mk2 charging knob in the works that should hopefully fix that problem

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Mastergold2027

Discussion Starter · #11 · 4 d ago

Mk2 version. I'll show a picture later showing a size comparison but this version is smaller, lighter, and hopefully actually an upgrade 😅

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Sean K.

· #12 · 4 d ago

Mastergold2027 said:
My bad for the inactivity, I think for the time being I'm going to opt for the folding buffer tube adapter. Don't worry I still want to try and make some improvements to the FAST stock but I'd like to have something that makes it tad more shootable for now. The main 2 things I want to address on the FAST 3 are the cheek riser and the buttpad. Anyone know where I can get my hands on a folding buffer tube adapter? Doesn't seem like RobArms has them anymore.

Also, I'll share some pictures of the charging handle knob "upgrade" I did.

They still have pics of the adapters up on the site. Did you call/email to order whichever one you need?

robinsonarmament.com

Parts Guide

The XCR-L is 12 years old this year! Over the years, the XCR has been sold in...

robinsonarmament.com

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Flskunkape

· #13 · 4 d ago

Do you plan to make the finished product in brass? Too bad the first one was too heavy I liked the it's looks. I'm also looking forward to seeing the mkii on the rifle..

Mastergold2027

Discussion Starter · #14 · 3 d ago

Flskunkape said:
Do you plan to make the finished product in brass? Too bad the first one was too heavy I liked the it's looks. I'm also looking forward to seeing the mkii on the rifle..

I'm actually using bronze for this. It's a little harder and lighter than brass and will be less prone to getting all dinged up. Planning on drilling the cross hole for the roll pin this week wo I should have it all put together relatively soon.

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Mastergold2027

Discussion Starter · #15 · 33 m ago

Flskunkape said:
Do you plan to make the finished product in brass? Too bad the first one was too heavy I liked the it's looks. I'm also looking forward to seeing the mkii on the rifle..

As promised here are a couple photos with the "mk2" version.

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