Fitment guide

Airsoft Hop-Up Bucking Finder

Buckings interchange by hop-up chamber standard, not by gun model. Match your gun to one of the four standards below to see every compatible airsoft bucking and nub we track, with prices compared across retailers. We cover 4,014 distinct buckings and 531 nubs and tensioners across AEGs, gas pistols, VSR snipers and gas rifles.

AEG Hop-Up Buckings

AEG hop-up buckings fit the standard electric gun chamber shared by almost every Tokyo Marui-compatible AEG: M4 / AR, AK, MP5, G36, SCAR, P90 and most others. AEG buckings are physically longer than GBB / VSR buckings and are NOT interchangeable with them. Brands like Maple Leaf, Prometheus, Modify, Lonex and G&G all build to this standard, so a bucking sold for one standard AEG generally works in another. The main exceptions are proprietary systems (KWA, Systema PTW, Krytac rotary chambers and Tokyo Marui NGRS / AEP), which need their own buckings.

1,610 buckings390 nubs 61 retailers from $0.74 1,473 in stock

VSR-10 & Bolt-Action Sniper Buckings

The Tokyo Marui VSR-10 is the airsoft bolt-action bucking standard, shared across the huge VSR-compatible ecosystem: JG BAR-10, Well MB series, CYMA, Maple Leaf and more. This short bucking is the SAME family used by TM-spec gas pistols and many gas blowback rifles, so VSR, GBB pistol and GBB buckings are routinely cross-listed. Because snipers are precision builds, VSR is where flat-hop and R-hop buckings are most popular for maximum range.

933 buckings79 nubs 52 retailers from $1.20 754 in stock

Gas Blowback Rifle (GBBR) Buckings

Gas blowback rifle bucking fitment depends on the system. Many Tokyo Marui-spec and WE gas rifles use the same short GBB / VSR bucking standard shared with gas pistols and VSR snipers. The important exceptions are VFC and GHK gas rifles, which take AEG-standard (longer) buckings instead. Because GBBRs vary, always confirm which chamber your specific rifle uses before buying.

775 buckings37 nubs 44 retailers from $0.89 579 in stock

Gas Pistol (GBB) Hop-Up Buckings

Tokyo Marui-spec gas blowback pistols (Hi-Capa, 1911, Glock / G-series, M9 and most clones from WE, AW, KJW and others) use the shorter GBB bucking standard. This is the SAME bucking family used by VSR-10 spring snipers and many gas blowback rifles, so GBB pistol, VSR and GBB buckings are frequently cross-listed and interchange. Match a GBB / VSR standard bucking, not an AEG one, since AEG buckings are longer and will not seat correctly.

696 buckings25 nubs 54 retailers from $0.64 570 in stock

What bucking fits my gun?

Your gunBucking standard
M4 / AR-15, AK, MP5, G36, SCAR AEG (electric)AEG
KWA / Systema PTW / Krytac / TM NGRS / AEPAEG
Hi-Capa, 1911, Glock, M9 gas pistol (GBB)Gas Pistol
CO2 gas pistol (TM-spec clones)Gas Pistol
VSR-10, BAR-10, Well MB spring sniperVSR / Sniper
Gas / CO2 / HPA bolt-action sniperVSR / Sniper
TM MWS, WE gas blowback rifle (GBBR)GBBR
VFC / GHK gas blowback rifleAEG
GBB SMG (gas)GBBR

Tap a standard to see compatible buckings. Rotate your phone for fitment notes.

Which bucking degree (hardness) do I need?

Bucking hardness is measured in degrees (Shore A). Softer rubbers grip the BB harder for more hop but wear faster at high power; harder rubbers suit higher FPS. Match the degree to how your gun actually chronographs with your chosen BB weight, not just the softest option.

DegreeRough FPS range
50 degreeup to ~360 FPS
60 degree~290 to 390 FPS
70 degree~355 to 460 FPS
75 degree~420 to 490 FPS
80 degree480 FPS and up

Standard, flat-hop or R-hop?

Standard bucking

The simplest choice. A standard bucking works with your stock nub and is plug-and-play. For most players in the right degree, a good-quality standard bucking is the upgrade that counts.

Flat-hop bucking

A flattened contact patch gives a longer, more stable hop and better range. It needs a matching flat nub (for example a Firefly Namazu). A popular mid-level range upgrade, especially on DMRs and snipers.

R-hop bucking

R-hop bonds a patch into the bucking window for the flattest trajectory and the longest, most consistent range. Traditional R-hop is an advanced install, but drop-in R-hop style buckings such as the Maple Leaf MR Hop and 4UAD make the benefit far easier to get.

Frequently asked questions

How do I know which bucking fits my gun?

Buckings interchange by hop-up chamber standard, not by gun model. Almost every Tokyo Marui-compatible AEG shares the longer AEG bucking, while gas pistols, VSR-10 snipers and many gas rifles share the shorter GBB / VSR bucking. Match your gun to one of the four standards below. The main exceptions are KWA, Systema PTW, Krytac, Tokyo Marui NGRS / AEP, and VFC / GHK gas rifles (which take AEG buckings).

What bucking degree (hardness) should I run?

Match the degree to your FPS and BB weight. As a rough guide: 50 degree up to about 360 FPS, 60 degree around 290 to 390 FPS, 70 degree (the most popular all-rounder) around 355 to 460 FPS, 75 degree around 420 to 490 FPS, and 80 degree for 480 FPS and up.

What is the difference between standard, flat-hop and R-hop buckings?

A standard bucking works with the stock nub and is plug-and-play. A flat-hop bucking has a flattened contact patch for a longer, more stable hop and needs a flat nub (for example a Firefly Namazu). R-hop bonds a patch into the bucking window for the flattest, longest-range trajectory and is an advanced install, though drop-in R-hop style buckings (Maple Leaf MR Hop, 4UAD) make it easier.

Do I need a special nub for my bucking?

A standard bucking uses the stock nub. If you switch to a flat-hop bucking you need a matching flat nub. Nubs, tensioners and H-nubs are listed as a filterable product type on each bucking standard page.

Looking for something specific? Search all buckings or browse the full parts catalog.