TOP-DEAD-CENTRE (TDC) Hop Unit Assy AEG M4 v2

The hop unit behind the NUPROL DELTA Series. True TDC vertical pressure, a pre-installed Flat-Hop and a finely adjustable rotary dial give predictable, stable flight and handle BBs well into the 0.30s.

• True TDC (top dead centre) vertical pressure from a hinge-pivot assembly
• Pre-installed Flat-Hop: a specialised bucking and nub with a larger, uniform contact patch
• Uniform pressure across the hop rubber for predictable spin and flight
• More range, lift and stability, particularly with heavier BBs
• Rotary dial for incredibly fine hop adjustment
• Handles heavier BBs well into the 0.30s
• The same hop unit fitted to NUPROL DELTA Series AEGs
• Aftermarket upgrade for most M4 AEGs on the market

The NUPROL TDC Hop Unit Set is the hop unit behind the NUPROL DELTA Series AEGs, and the reason they shoot so well. It can now be fitted as an aftermarket upgrade to most M4 AEGs already on the market.

Most hop units use a single engagement arm that swings down onto the hop rubber. The arm moves on one pivot, so the pressure reaches the bucking at an angle rather than straight down. That works with lighter BBs, but standard single-arm hops start to struggle once you go past 0.28 g.

The TDC assembly uses a hinge pivot instead, giving true TDC vertical pressure: straight down on top dead centre of the pre-installed Flat-Hop. Flat-Hop is a specialised bucking and nub with a larger, uniform contact patch. It spreads the hop pressure evenly across the rubber, so the BB picks up spin the same way every time and flies predictably. The result is significantly more range, lift and stability, particularly with heavier BBs. The rotary dial offers incredibly fine adjustment, so you can dial in exactly the right hop.

Together, TDC, Flat-Hop and fine dial control give excellent flight control on V2 M4 AEGs, with the grip to fling heavier BBs well into the 0.30s. The hop unit is one of the most important parts of an M4 AEG for performance on the field, which makes this an essential upgrade for players and an essential product for retailers to stock.

• What does TDC mean? Top dead centre. The hop pressure is applied vertically, straight down on the centre of the bucking, rather than at an angle.
• What is Flat-Hop? A specialised bucking and nub with a larger, uniform contact patch. It applies the hop pressure evenly across the rubber for predictable spin and flight, and significantly increases range, lift and stability, particularly with heavier BBs.
• What BB weights can it handle? Standard single-arm hops start to struggle past 0.28 g. The TDC hop goes well into the 0.30s.
• Will it fit my AEG? It’s designed for V2 M4 AEGs and fits most M4 AEGs already on the market. It’s the same hop unit used in NUPROL DELTA Series AEGs.
• How is it adjusted? With a rotary dial that offers very fine adjustment.