M*CARBO Brotherhood

Spare Magazine Holder On S2K Buttstock For Glock

This was requested on another thread and here it is. It’s one of the better options for mounting a spare magazine holder on the S2K. Faster and easier than a belt mounted mag holder when performing a tactical reload and it doesn’t affect the maneuverability of the gun. The position of the holder is adjustable in 2 directions and is offset so it doesn’t interfere with the charging bolt. I use Picatinny rail to store my red dot scope on a quick release mount when I am using it as a truck gun. Scott

Spare Magazine Holder on S2K Buttstock for Glock Magazines

Parts Used:

Monoki Keymod Picatinny Rail Sections, 5-Slot 7-Slot 13-Slot Lightweight Picatinny Rail Section for Keymod Handguard Mount Rail System (5/7/13-Slot) $14

Monstrum Tactical Lockdown Series Adjustable Height Riser Mount with Quick Release (2.5 inch Length with Quick Release) $15

Glock GLKMP17076 Mag Pouch 9Mm/40/357 Cal $10

Fasteners $3

Two size 6 - 3/4” flat head stainless steel screws

Three size 6 - 1/2” round head stainless steel bolts

Three size 6 stainless steel nuts

Three size 6 stainless steel washes

Amazing GOOP 170011 Marine Adhesive, 3.7 Fluid Ounces $8

Total Cost: Around $50

Installation Steps:

  1. Attach 7 slot, 3” Picatinny rail to the buttstock with two size 6 - 3/4” flat head stainless steel screws and Marine goop.
  2. Remove the left belt attachment on the mag pouch with scissors.
  3. Remove the upper section of riser mount and drill 3 holes for the bolts.
  4. Drill 3 holes in the right mag pouch belt attachment to match the holes in the riser mount.
  5. Apply Marine Goop to the areas of contact between the mag pouch and riser mount then install the bolts. Tighten the nuts until finger tight only. Apply more Marine Goop in between the nuts and the riser mount.
  6. Put a magazine in the mag pouch. If the pouch is perpendicular or 1-5 degrees angled outward, you do not need soapily a clamp. If the pouch is angled out more than 5 degrees, use a clamp to bring the pouch to 5 degrees. Check the retention of the pouch. If it is too tight, release the clamp a little until the retention is correct. Let the glue dry for 48 hours.
  7. Paint the heads of the bolts with paint or finger nail polish. (optional)


That is very ingenious @Scooter! Very clean and professional. Makes the factory buttstock more aesthetically pleasing and functional. I’d pay fiddy bucks for that.

Thank you for the exceptional pictorial. :+1:


@Scooter, Good looking out for the group! Very clean and nicely done. Props on the pictorial and explaination. I will surely enjoy this project for my own S2K. You guys are giving me such great ideas… Now to ‘afford’ my new adventure!


I like spare charging handle attached to the buttstock.


Concept is there, just looks really awkward.

From an ergonomic perspective, it is pretty comfortable. Only a 90 degree turn to index the mag vs 180 degrees for a belt mag. Shorter distance too.

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I wanted to make a second version with the hopes of not having to use the clamp. I drilled the holes partially on the raised area which eliminated most of the bowing which required the clamp to correct. The plastic on the Glock Mag holder is super thin and deforms easily. “Glock Perfection” LOL.

On the upside, version 2 is an easier and cleaner design. On the downside, the OEM mag retention is a little loose. It can hold a G19 or G17 upside down in normal use but probably not rough use. The clamping in version 1 provided better mag retention which you could adjust while the glue was setting up. I think either version is fine in normal use.

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From Amazon Tulster NeoMag

Just found this.