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How to modify your SCAR grip tang & fit MIAD backstrap

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61K views 62 replies 30 participants last post by  PsYkHoTiK  
#1 · (Edited)
I for one do not care for the A2 grip. It's doable, but not something desired. Better grips are out there. I like the Magpul MIAD and MOE.

The FN Scar lower was molded incorrectly with an oversized grip tang. You could not simply remove the A2 grip and replace it with an after market one unless the grip tang cavity on the grip was oversized.

I called Bob (FN) and Jeff (Tangodown) and they said the same thing. Modify the grip or the tang. With the release of the black Scar, I had hoped that FN "corrected this", but no joy.

Two options....mod the grip or mod the tang? Modding the grip will weaken the grip (less cross sectional material left over when done) and you can't use another grip down the road. Mod the grip tang and you can attach almost any grip provided it didn't have a backstrap. So you could use a Hogue. Downside.....if you FUBAR the tang.....your fXXked.

So, here we go......(it is your resposibility if you FUBAR this up. I take no liabilty for YOUR mod.)

BE SURE ALL WEAPONS ARE UNLOADED!! :?

I presume that anyone that has a Scar, already has a M4 and clones. If so, this will go much quicker.

Here's my Colt 6920 (that I know is in spec). Remove pistol grip.
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Take a piece of paper so that you can use the corner to overlay against the grip tang. Crease along the three edges of the grip tang. Cut along the creases and corner. This will give you a rough template of the in spec grip tang. Trim the template to fit better on the M4 grip tang.
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Here's the template.
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Tools that make the job easier: safety glasses, dremel, medium grinding wheel, fine polishing wheel, flat file, pencil or marker.
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Again, be sure your weapons are unloaded!!
Remove grip from Scar. Use your new template and overlay it on the Scar grip tang. As you see, there is too much material on the diagonal edge. Approx. 1/8". (I already started grinding, so there's not much left against the template) Once that is removed, the other edges come into close to spec with the template. Use a pencil to mark the excess limit to remove.
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WEAR SAFETY GLASSES!! You'll get hot shards of plastic in your face depending on the rotation of the Dremel wheel.

GO SLOW if you use a Dremel and leave plenty of room to hand file for the final fit of the edges. Use the flat file to make sure the grip tang is flushed!
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Check for grip fit every so often.
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Personally, I like to choke up on the grip and the B1 backstrap is no better than the A2 grip to begin with. I wished someone else had posted a "How to do for dummies", since I wasted a MOE during the "learning process." :-(
This is the B3 backstrap I used as the "second" try. You can see the interior profile needed from the rear view.
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Here's the B2 backstrap on the left with the needed profile and the MOE on the right with a much shallower profile.
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Here's the top view of the needed contours of a B2 backstrap.
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BE CAREFUL GRINDING AWAY NEAR THE EDGES. I got too close on the MOE and B3 backstrap and caused a flat edge on the upper right curve as seen below. (MOE on right, B3 in the middle, B2 on the left).
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Go slow and try fitment.
Finished end results.
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The MOE was my first attempt. The B3 was the second and I got the profile needed down pat. The B2 was the final attempt. I did it in a minute. Remember to stay away from the edges or grind there too long. You don't want a flat when it should be a curve.

I used the original Scar grip screw and checked for clearence with the trigger components. Cleared fine. IF YOU REMOVE TOO MUCH MATERIAL FROM THE DIAGONAL FLAT OF THE SCAR GRIP TANG, THE FACTORY SCREW MIGHT CONTACT THE TRIGGER LOWER FLAT. IN THAT CASE, A CUTTING DISK IS HANDY.

And no I did not do this in my living room. A good vacuum can hide evidence. :D

Hope this helps someone out! :?

 
#27 ·
This mod is not for everyone.
Seems that FN has still not made the correction to the tang. :th_tsk:

However, TD has released their pistol grips to fit the new tang, if you like that grip profile.

FWIW......I applaud all who mod their sticks as to fit their needs. Takes brass ones for this.
 
#28 ·
I got a new SCAR 16S yesterday, bought the MAGPUL MIAD Grip. It fits great with the backstrap that does not curve around the body of the rifle. The biggest problem I had was figuring out how to remove the "bolt" down inside the handle. I finally got it moving with a ratchet but could not get it out. Turns out it takes a large Allen/Hex wrench, hard to see even with a good flashlight. Fortunately I had just bought a 43 pc Kobalt set on sale at Lowes. It takes a long one to reach down into the handle. Not sure if FN or MAGPUL may have made changes. I imagine I would have to alter the straps that curve around the body of the rifle but the frame of the rifle curves there anyway. I'm not sure what using one of those curved straps would accomplish unless someone with larger hands might prefer the grip/frame joining point to be a little thicker. My hands are liking the MAID Grip with the plane rear strap and it seems to fit well out of the box.
 
#29 ·
SCAR 16 with MIAD install

Here is my finished MIAD. I did grind down my lower by about 1/16th inch though to get the gaps to fit perfectly (the MOE grip requires about an 1/8 inch). The back strap was obviously ground down as well, but looks good. I still need to grind down the sharp corners that stick out by the trigger guard - apparently the SCAR trigger guard is not as wide as on an AR.

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#33 ·
Every time I see pics like yours GoldenGun showing a nice clean job it really makes me want to tackle this. I've gotten used to the A2 grip, but part of me always wonders about that MIAD.

Does anyone have precise measurements of an in-spec grip tang for someone like me who doesn't own an AR?
 
#34 · (Edited)
e0603,
It's the "A2" grip tang from Colt. There should be a TMP/TPP of the tang, since it's public info. Ergo has released a Scar specific grip in black and FDE. Make sure you order the correct ones as the Scar ones have a different SKU.

PM me your address. I can cut out a template from my Colt and send it to you. Or I can scan it and email you and you can cut it out. :biggrin:

It's a really easy mod, if you go slow and take your time. You shouldn't have to "get use" to your equipment, mod it to your needs.
 
#35 ·
I cut a template from a Palmetto Lower I had sitting around out of two post it notes. I duct taped around the spots I wanted to watch and hit it with a plastic grinding wheel on the dremel. When I got about 2mm away from where I wanted to be. I switched over to the plastic medium cut file. I then switched to some modeling sandpaper. You tell me how it turned out.

Scared sh!tless to do it, but super happy I did it!

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Thanks DOE!
 
#39 ·
You have to remove very little to get the 'grip' part of the MIAD to fit. I had my misgivings too, but it was super easy. I just lightly touched the scar's lower to a bench grinding wheel and wa-la, the MIAD slipped right on. Highly recommend this mod. My next thought might be to try a bcm battlegrip due to its sharper angle.
 
#40 ·
I did it. Basically just take off 1/8 from scar level from bottom. No need to measure with previous AR. Practice first with the opposite one you do not want and it will go easy. If you are using a dremel, use the lowest setting, grab a coffee and take your time. To remove the rind use your finger nails. Make sure not to slip UP AND AROUND the other end as I did, a nice scrap but hell, its a gun and on the right side of the gun so you cant see it unless you are looking for it. The edges will become VERY brittle. Face it, it will NOT fit perfect where beaver tail is, at least I had quit ahead. I have about a 1/16 inch gap but it is nothing to worry about and even notice unless you are looking. Lets face it, the A2 grip blows and the MIAD is really a nice update. Conservatives can store batteries and liberals can store medical marijuana in the grip :lol:
 
#44 · (Edited)
Using the OP's write up I modified the grip tang and documented with photos. I gotta tell you.. your balls tighten up the first time that dremel touches the lower but after that it gets easier. Now I can use any grip I want. So here we go...

As you can see... that gap is unacceptable. Since the top of the handle isn't in contact with the lower not only does it have the potential to accumulate crud it also cause undo stress on the tang because the pressure isn't distributed correctly.


The rifle I used for the template (Spikes tactical Piston AR15) laid next to the SCAR.


Just for ****s I stuck the ergo from the AR on the scar to see what kind of gap that would have and as you can see...


Laying my template paper on the AR's Tang I pressed firmly along the edges until I had some nice visible creases to identify the cuts I needed to make.


Self explanitory.
 
#45 · (Edited)
Again self explanitory and yes that is a PS3 instruction manual lol!


This is a close up of exactly how much extra material the good folks at FN have manufactured on the SCAR tang.


I used an exacto and cut a line using the template of the material that needed to be removed. As you can see there is still a ton of plastic behind that line so this wont affect the integrety of the tang IMHO. I know it's a heavier rifle then then the AR but who's heard of an AR's grip tang breaking off? Yes I am talking about the polymer lower AR species. In any case getting to the P.O.N.R.


Luckily I had this at my disposale.


This is the sanding drum I used to remove the material. I had it on the 3rd speed setting to get it to sand smoothly. Taking my time and trying the Hogue repeatedly I removed a little bit of material at a time until I got it. 10 minutes max.
 
#46 · (Edited)


And here is the finished product. I got to do a little at home gunsmithing project which I love and I am very happy with the finished product. Next to tackle the MIAD. On a side note after I removed the material with the sanding drum I used a metal polishing wheel and smoothed out the tang so it's nice and pretty again. Thanks OP for the inspiration to do this.
 
#47 ·
I wonder why they dont make a scar specific MIAD? Maybe there is one in the works. oh well now I can use whatever I want ://:
 
#51 ·
Okay I got my magpul miad this week and I don't have a template to start hacking away at my lower. Even worse I don't have the heart to do it lol. Can you just mod the grip to fit the scar? I really hate the original grip. Worse comes to worse I can probably put it on my sig 556 but really want to change out the scar grip
 
#53 ·
Do you own a printer? If you do make a printout of the seal that sgt designed: You may have to play with the size a bit. Then just cut out his grip tang: Then put it on cardboard and you have a templete> Or even less complicated. Measure a 1/16 " up the tang and take it down to that. That's what I did. Then I took just a tad bit more off and it fit perfect: The tang isn't a different shape it's just slightly smaller on a standard AR: The back strap is simply trial and error. I haven't messed with that. I figure eventually someone will make a cool grip for it. The tangodown Grip fits, but I personal don't care for it.
 
#56 · (Edited)
For those without an AR-15 lower for a template it is simple to do this mod without it. This is the single best picture here in this thread that shows exactly the single flat cut needed on the lower:

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I understand the sentiment not wanting to mod or screw up your lower. That being said modding the lower by far makes the most sense. SCARs are relatively low volume and you can't count on many custom grips being made. Once you mod your lower pretty much any AR-15 grip will fit (perhaps less a small mod to to the backstrap if present (like MIAD)). That to me is the big secondary benefit - permanent widespread compatibility with an industry "standard".

Go for it!