MBW works continuously to lower maintenance and extend life expectations of its rammers. MBW rammers feature the industry's only percussion system completely free of high friction/heat/wear metal-on-metal reciprocating wear surfaces. The patented design features c-shaped, non-metallic, slide bearings between spring separator and spring box, ram shaft and spring box, and spring box and guide tube. Wear characteristics of the MBW bearings are several times better than traditional steel-on-cast iron designs.  Lower operating friction/heat provide positive implications for engine, lubricant and bellows life. Unlike stiff plastic bellows, the MBW vulcanized rubber bellows with stranded steel enforcement reduce jobsite punctures and is far more resiliant to UV degradation. In the event percussion system lubricant is lost, MBW percussion systems are designed to fail a single slide bearing, locking up the system and preventing damage to other bearing surfaces, as well as bearings and seals in the rammer's gearbox. Because MBW percussion systems generate less internal friction, rammers operate more efficiently, consume less fuel, and deliver more compaction force for the purpose intended. When replacement is eventually called for, MBW slide bearings are replaced at low cost, returning percussion systems to original specification.


Endurance testing of the new design exceeded even MBW's expectations. As a result, MBW gas powered rammers now provide a 5 YEAR WARRANTY on percussion system slide bearings and bellows.

LIMITED WARRANTY. Some restrictions may apply.

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The 422 & 442 Rammers are ideally suited for the compaction of granular, mixed and cohesive soils in confined areas. A mainstay in contractor and municipal fleets, the 422 & 442 offer highly productive percussion rammers at 145 up to154 lbs. (66-68 kg). The contoured fuel tank provides the largest fuel capacity in its class and effectively baffles engine noise. Power is supplied by Honda engines. Model 442 delivers approximately 25% more compaction force and is recommended for heavy clay soils. Available with a choice of two engines...Honda GX100, Honda GX100 with oversized air filter or Honda GXR120

• Elevated bellows placement for trench applications
• Patented polyethylene slide bearings provide minimal internal wear
• 11” ductile cast iron tamping shoe
• 4” and 6” trench shoes available for the 422

US & International Patents

R422 R442 AR56 AR57
Shoe Size 11 x 13 in (28 x 33 cm) 11 x 13 in (28 x 33 cm) IRON 11 x 13 in (28 x 33 cm) ALUM 13 x 15 in (33 x 38 cm)
Engine Option Honda GX100 (145 lb/66 kg)
Honda GXR120 (145 lb/66 kg)
Honda GX100 w/Oversized Air Filter (149 lb/68 kg)
Honda GX100 (150 lb/68 kg)
Honda GXR120 (150 lb/68 kg)
Honda GX100 w/Oversized Air Filter (154 lb/70 kg)
Travel Speed Up to 55 ft/min (16 m/min) Up to 55 ft/min (16 m/min) Up to 60 ft/min (18.3 m/min) Up to 60 ft/min (18.3 m/min)
Compaction Depth* Up to 18 in (45 cm) Up to 18 in (45 cm) Up to 24 in (61 cm) Up to 24 in (61 cm)
Compaction Area 3025 sq ft/hr (281 sq m/hr) 3025 sq ft/hr (281 sq m/hr) 3300 sq ft/hr (307 sq m/hr) 3900 sq ft/hr (362 sq m/hr)
Percussion Rate Up to 720 blows/min Up to 720 blows/min Up to 650 blows/min Up to 650 blows/min
Weight 124 lb (56 kg) 126 lb (57 kg)
Height 42.5 in (108 cm) 42.5 in (108 cm)
Width 13.5 in (34 cm) 13.5 in (34 cm)
Length 24.75 in (63 cm) 24.75 in (63 cm)
Air required 100 psi (75 cfm) 100 psi (75 cfm)
RPM 4500 4500
( ) Metric Measurements.
​Specifications subject to change without notice.