Rails, stocks and grips on a used gel blaster and what actually transfers

Both my main blasters, the MK18 and the N4, are on Picatinny quad rails: square-slotted rail on all four sides of the handguard. It’s the old-school setup, heavier than the slim modern handguards, and the holo sight I run on both clamps straight onto it.

That last point is the whole post. What matters about furniture isn’t how it looks in the listing photo. It’s whether it works with what you already own, and whether any of it comes with you to the next blaster.

Three rail systems, told apart from a photo

Picatinny (MIL-STD-1913). Square-edged slots across the rail, 5.23mm wide at 10.01mm spacing. Optics, lights, grips and slings all mount with a clamp. Quad rails like mine have it on four sides.

M-LOK. Long rounded slots running along the handguard. Accessories bolt on with a small T-nut that drops into the slot. Slimmer and lighter than a quad rail.

KeyMod. Keyhole slots, a round hole with a narrow tail. It uses its own nuts, so M-LOK accessories don’t fit it without an adaptor. In a 2017 test for US special forces at NSWC Crane, M-LOK held 215% more average load than KeyMod when pulled off-axis, and shifted point of aim less after accessories were refitted. If you’re choosing between the two, that test is a good reason to favour M-LOK.

What moves to your next blaster, and what doesn’t

Usually moves: anything that clamps or bolts to a rail. Optics, lights, foregrips, hand stops, sling mounts. A Picatinny-clamp accessory fits any Picatinny rail, and short Picatinny sections bolt onto M-LOK or KeyMod.

Sometimes moves: pistol grips. Many AR-pattern blasters share a grip pattern, but gel blaster grips often hold the motor, so check before you buy one for a different blaster.

Usually stays: handguards and stocks. Handguards mount to maker-specific barrel nuts. Stocks slide onto the tube at the back of the receiver, and on many gel blasters that tube also holds the battery and wiring, so it isn’t always a standard size. Ask for a photo with the stock removed before you buy one blaster for another’s stock.

🟣 Price the furniture as part of this blaster, not as money in the bank

Checks before you pay

Grab the handguard and twist. Any rotation or flex where it meets the receiver is a condition issue.

Check the battery space. If the battery lives in the stock tube, check a tight stock hasn’t pinched it. A damaged LiPo is the one fault here that’s actually dangerous (QFD battery safety).

Weigh it. An alloy handguard, a heavy stock and a big foregrip add weight in front of your hands. Fine at a static position, tiring over a three-hour game. New players are usually better off lighter.

Know what furniture doesn’t do. It doesn’t change how a gel blaster groups. That comes from the hop-up, the barrel and the gel (gel size and barrel fit).

Frequently asked questions

How do I tell M-LOK and KeyMod apart?

M-LOK slots are long rounded rectangles running along the handguard. KeyMod slots are keyholes: a round hole with a narrow tail. Picatinny is a ladder of square-edged slots across the rail.

Can I put M-LOK accessories on KeyMod?

Not directly. They use different nuts. Adaptors exist, or you can bolt a short Picatinny section onto either and use clamp-on accessories.

Will my stock fit another gel blaster?

Often not. Stocks slide onto a tube that, on many gel blasters, also holds the battery and isn’t a standard size. Check the tube before you buy.

How much do extras add to a used gel blaster?

Less than the receipts. Accessories sold on their own on RedSpear took a median of 104 days and usually sold under asking. Value them for what you’ll actually use.

Sources

• Wikipedia - Picatinny rail (MIL-STD-1913 dimensions, Weaver compatibility)
• Soldier Systems Daily - USSOCOM-sponsored KeyMod vs M-LOK test at NSWC Crane (2017)
• RedSpear Armory Shopify sales data, May–October 2026 (used items, with days from listing to sale)
• Queensland Fire Department - Lithium-ion battery safety

Last checked: 31 October 2026.

RedSpear Armory — Queensland's dedicated marketplace for used gel blasters. Browse listings, sell your gear, and connect with the local QLD community at redspeararmory.com.au.