Accuracy International Thumb Rest

[samb300]

Hey everyone,

I designed and made a custom 3D printed thumb shelf for the AT and AX platforms. I wanted to share some pictures and information to see if anyone else would be interested in them.

The unique part about this design is how it bolts to the chassis with ZERO permanent modification whatsoever. It will work on both the AT and AX, at this point I’m not sure if it will work on the AE or AW. I utilize a printed insert with a threaded feature to replace the AI logo button (you know, the one that always falls on the floor when you take the skins off ?). Then a second screw threads into a metal insert in the chassis itself. So other than a 2.5mm Allen wrench and a pliers, no special tools are required.

This thing is rock solid. I made a few revisions and have the size/shape to where I like it, but I will be sending some prototypes off to friends to test out and give me feedback. So what you’re seeing now is a sort-of-final prototype.

With the AT install, the thumb rest will delete the bolt-side flush cup. On the AX install it will delete the plastic “stock capture” piece, meaning the folding stock won’t click in place anymore. But it will still fold all the way and not contact the thumb rest.

Let me know what you think, and if you’d be interested in buying one when the design is final. I don’t have a firm price, but I’m thinking it will be in the neighborhood of $30. It will be available in right and left handed versions.

If I get some interest, I will create a Group Buy thread and go from there.

Thanks!

 

[Nik H]

I'm in for the LH version which needs to come out before the RH version

 

[TheOE800]

What is this left-handed nonsense?

 

[samb300]

What is this left-handed nonsense?

Thankfully CAD and 3D printers work in the non-Devil’s hand dimension as well ?

 

[jordan0317]

I'm down for a right handed one

 

[samb300]

Right hand version...

 

[Basher]

In for a right-handed AT version!

 

[PBWalsh]

F you!!

I was dead set on a Mausingfield/KRG and you had to go and do this. Serious 1st world problems.

If I had an AI... or maybe when I get an AI, I’d buy it for both sides.

 

[samb300]

F you!!

I was dead set on a Mausingfield/KRG and you had to go and do this. Serious 1st world problems.

If I had an AI... or maybe when I get an AI, I’d buy it for both sides.

Hopefully not to rain on your parade, but as it is it won’t work having a thumb rest on both sides. There is a flush cup on the weak hand side that threads into a metal insert, and the thumb rest threads into that insert as well. So if that weak side flush cup gets deleted, I’d have to come up with some special replacement insert that both thumb rests screwed into. It’s possible, just something I haven’t worked on.

 

[samb300]

Forgot to mention that this gives a nice place to put your thumb when shooting free recoil so you don’t have to wrap it around the back of the grip!

 

[Covertnoob5]

In for 2 rights.

 

[PBWalsh]

Hopefully not to rain on your parade, but as it is it won’t work having a thumb rest on both sides. There is a flush cup on the weak hand side that threads into a metal insert, and the thumb rest threads into that insert as well. So if that weak side flush cup gets deleted, I’d have to come up with some special replacement insert that both thumb rests screwed into. It’s possible, just something I haven’t worked on.

Realized that after looking at the pictures more. Looks like a win for AI folks. I just need to decide on the rifle and get to shooting. I’d be in for 1 right version if I go with an AI.

 

[samb300]

Realized that after looking at the pictures more. Looks like a win for AI folks. I just need to decide on the rifle and get to shooting. I’d be in for 1 right version if I go with an AI.

You won’t regret getting an AI!

 

[samb300]

Here’s a couple of videos I made to go over what the thumb rest looks like and how it gets installed.

 

[MarinePMI]

I'm in for a right hand version.

 

[buffybuster]

I'd like to test fit on an AIAE MKII & III

 

[samb300]

I'd like to test fit on an AIAE MKII & III

I think it's possible on the AW and AE systems, however - these chassis do not have the hole going through them, and the skins don't have either of the holes. It would require a special metal insert, along with permanently modifying the chassis.

Right now, I'm going to focus on the current design for the AT and AX. Once these start going out and I get some feedback, I may consider looking into this, but I can't promise anything. Thanks!

 

[Serpico1985]

I'm in for a right hand AT version

 

[TheOE800]

Thankfully CAD and 3D printers work in the non-Devil’s hand dimension as well ?

I’m interested, but losing retention of the stock kinda sucks.

 

[samb300]

I’m interested, but losing retention of the stock kinda sucks.

Yup, there's certainly no easy way around that. The plastic retention piece on the AX threads into the metal insert through the chassis, which is where the thumb rest bolts into.

Personally, the factory retention piece got in the way when I tried to shoot with my thumb on the side. I find it to be obtrusive, and I never "need" to retain the folded stock for my use (match / range practice / cleaning). But that doesn't mean that others don't need the stock retained for packing or hiking with it folded.

I will look into it a bit more for the AX model. I think I could design a separate piece that potentially fits, but it would have to not protrude beyond the face of the thumb shelf so that it didn't get in the way. Not sure how much retention force that would have on the stock, and not sure how durable those 3D printed "fingers" would be that held on to the metal button.

 

[Delta24]

Interested in a right hand AT version as well.

 

[pineoak]

Consider a smaller backstrap in the future. I wear XL gloves but prefer a different grip angle (more vertical) than the factory grip.

 

[samb300]

Consider a smaller backstrap in the future. I wear XL gloves but prefer a different grip angle (more vertical) than the factory grip.

Good idea. I’ll look into it and see how much I could take off the “hump” of the factory backstrap. Only challenge is the lower screw does stick out pretty far on the frame of the grip.

 

[Badfinger]

In for a right-handed version!

 

[pineoak]

that looks great! consider a 2nd option that also fills up the top of the backstrap as well for a more vertical (not completely) grip, would require larger hands or used in conjunction with the thumb rest (combo offer?) for a more vertical grip like the MPA

 

[Aaron47pb]

I shoot with my thumb up, not wrapped around the grip, and I'm struggling to understand the point of the thumb shelf. Is it just personal preference or is there a practical reason to have something to rest your thumb on?

 

[TorF]

Why don't you add thickness, in your case, to the left side of the grip. In effect the grip will be off center. Then the position of the hand will be more natural and comfortable. If you get problem with reaching the trigger you can add a wide trigger shoe. You can then almost use the bolt handle for thumbrest and have an extremely good layout for rapid fire.

 

[PBWalsh]

I shoot with my thumb up, not wrapped around the grip, and I'm struggling to understand the point of the thumb shelf. Is it just personal preference or is there a practical reason to have something to rest your thumb on?

For me I like having a consistent resting place for my thumb. A good thumb rest/shelf helps me build a consistent grip every time, like a reference point. I also find it uncomfortable to have my thumb float in the air.

 

[samb300]

I shoot with my thumb up, not wrapped around the grip, and I'm struggling to understand the point of the thumb shelf. Is it just personal preference or is there a practical reason to have something to rest your thumb on?

I think the root of it is the balance of forces. For me, when I wrap my thumb around the back of the grip, the web of my thumb is resisting the trigger pull in the opposite direction...so I get a consistent pull and break each time. When I shoot with my thumb on the side "floating" like PBWalsh mentions above, I find that the only thing acting in the opposite direction of the trigger pull is a small portion of my palm. With a sub-1 lb trigger pull that isn't a big deal, but with a 3 lb trigger pull it makes it hard (for ME) to be as consistent. I think the thumb shelf helps in giving a repeatable position, and for balancing out the trigger pull force when shooting with the gun loaded in your shoulder or with free recoil.

If you look at other chassis and stocks, you'll see that the MPA, KRG, new Magpul, etc, along with traditional Manners and McMillan stocks, give you a consistent place to put your thumb on the side should you choose.

 

[impactaddict]

I'd be in for a right handed AT version when they're available.. It looks like it'll beat my QD mount hack.

 

[goldenbear926]

Count me in for a right hand AT version as well.

 

[LawnMM]

Nicely done!

 

[mkollman74]

I'd take a lefty AT version. Thanks for your work on this. In terms of unsolicited feedback I'd prefer a flatter, not "upswept" rest.

 

[Jeffd]

I will take 2 RH AT and 2 RH AX

 

[Ruggedtouch]

Very clever mod.

I'm in for a RH, AX version.

 

[samb300]

I'd take a lefty AT version. Thanks for your work on this. In terms of unsolicited feedback I'd prefer a flatter, not "upswept" rest.

Thanks for the feedback. I'm hoping to hear back from some of my testers soon to see what they do and don't like about the shape and feel. In all honesty I tried to replicate some of the MPA thumb rest shape/contour - and combined with my hitchhiker thumb - this is the initial version I arrived at. I'm somewhat limited in room since I can't go a lot lower without interfering with the knuckle of the trigger finger, but the angle and shape can certainly be tweaked if that's what people want.

 

[samb300]

Just an FYI for everyone, I should be getting the metal inserts for the AT version soon. Once I do, I have a few more testers to go out to buddies with ATs. Then it will be a matter of finalizing the design, and making sure the printed piece is exactly how I want it.

I hesitate to put a timeline on everything, but my hope is I will have the feedback I need in the next couple of weeks as friends start their match seasons.

Thanks again everyone for the interest!

 

[phlegm]

Good idea. I’ll look into it and see how much I could take off the “hump” of the factory backstrap. Only challenge is the lower screw does stick out pretty far on the frame of the grip.
View attachment 6897251

I've contemplated buying a 3D printer just for this ability.

 

[Fitz]

Am in for a right handed AT as well.

 

[OzzyO20]

100% in for a right handed AT.

 

[Dave62677]

In for right hand AX

 

[Sniperwannabee]

So what's the reason not to wrap your thumb around ?

 

[Sogan]

So what's the reason not to wrap your thumb around ?

You will see both. Really comes down to personal preference. However not wrapping my thumb feels more natural when shooting a precision gun and could prevent me from torquing the gun one way or another due to the awkward grip when pulling the trigger

 

[96C]

Following, good work Sam!

 

[mpk1996]

I'd be interested in one for right hand AX, especially if it came in TAN!

 

[samb300]

Hey everyone, here’s an update on the thumb rests:

I got the first batch of metal inserts for the AT yesterday, so my plan is to borrow my buddy’s AT next week to ensure the installation will work as planned. I’ll make an install video for the AT when I put it together.

Once I confirm it works on the AT, I will be sending the last couple prototypes out to be tested by some friends. I am also working on a few tweaks for the final design, so those changes - along with any that come from user feedback - should make the final version even better.

My buddy (with the AT) and I will be shooting a local match the first weekend in June, then a 2-day PRS match the following weekend. My hope is that I’ll have the final prototype on hand to test at those matches, so we can get a bunch of rounds downrange to make sure the thumb rests work.

I will keep you posted with updates, with a goal of having final parts ready to ship by the end of June. Thanks!

Sam

 

[*Tavman*]

This is great. I've been considering an AT and the lack of a thumb shelf was a major bummer. I'd be in for the left handed version.

 

[hypno02]

In for a righty AT

 

[03psd]

In for a right AT

 

[samb300]

I got the AT version installed and confirmed that it will work. Here’s a picture and an installation video to tide you over. I’m still planning on having parts ready by the end of June.