UMAREX SERVICE KIT FOR T4E HDR .50cal

The Umarex HDR 50 Service Kit contains all the essential components needed to quickly repair your HDR 50 revolver. Standard spare parts set of the manufacturer.

• Trigger reset torsion spring (Larger spring)
  
• Rebound torsion spring (Smaller spring)
  
• O-ring (11 x 1.2 mm) - For the brass screw which the pressure indicator nub protrudes out of. Use some silicone grease to slip it over the brass threads and definitely use an angled O-ring pick.
• O-ring (6 x 1.5 mm) - The small cyan one, fits in a female groove, at the end of the tube opening of the tube that the valve fits over
  
• Valve seal / square tube O-ring (17 x 3.3 w/ rounded inside flange) (The flat buffer, that looks like a rubber washer). This slips over the aforementioned tube.
• Bump cap assembly w/ O-ring factory fitted - full assembly. Usually only for if you lost yours.

Otherwise, in terms of general maintenance, we recommend;

1. The exterior can be cleaned using a simple wet cloth and some SUNLIGHT. Use a toothbrush to get into the smaller areas like screw holes and the Picatinny rail slots. Just mind that the screws can and will rust, so something like WD-40 afterward, or, once dry, a dab of multipurpose lubricant to remove rust / prevent it forming. PLEASE DO NOT SUBMERGE your HDR50 into water - the springs inside are spring-steel, have no corrosion resistance and will readily rust up if exposed to tap water.
2. Into the trigger and in via the area tfrom which the magazine stopper emerges, you should spray some multi-purpose lubricant. This will counteract the formation of rust on the springs inside the trigger and indexer assembly
3. In terms of O-ring lubrication - use RUBBER GREASE on the green O-ring on the bump cap assembly. In terms of lubricating the internal O-rings - you don't chuck a few droplets of SINGER 3-in-1 OIL into the pressure chamber where the CO2 capsule would be pressurized. Try and aim for the little hole on the brass disk w/ the flat drive slot when dispensing. Don't use any petroleum based substances to lubricate here - that includes Q20 / tool in a can. You can use SILICONE spray as well, if you have the long john nozzle to reach to that little hole.

If you want to buy a replacement bump cap because you cross-threaded the threading at the base of the handle - then the damage is likely a little more extensive and just replacing the bump can will not solve the problem - the threads will have to be redone or the pressure chamber replaced. You should however, be able to manage simply by rotating the pressure chamber around - the top part then (the threading is usually just staked) can be sealed up gas tight w/ the use of red thread adhesive. That will likewise, glue the threads together and prevent the pressure tube from slipping off. a Cheap product like NASCA thread adhesive will do the job.