Could you please help reviewing the following classification? :-)
In particular CP-BLK/CP-HW part, where naming is a bit confusing.
Over the years cartridge design has changed considerably. Dummy cartridges are still used, but as cap-firing and later blowback mechanism was invented, many modelguns can be found in several versions requiring different cartridges. Often they can be converted to another type of a cartridge, sometimes just by replacing detonator pin or modifying existing one.
dummy - usually made as a solid single-piece construction, sometimes with a positioning hole in the front. Dummy cartridges can be manually cycled through modelgun, or just used for decoration. Some cap-firing modelguns can be converted to cycle dummy cartridges by replacing detonator pin with one for dummies.
This type of cartridge is still widely used in a variery of modelguns.
open - early versions of cap-firing cartridges did not have any blowback action. All cap power was for effects, model had to be manually cycled. Cartridges used a simple, often single-piece design, where cap is inserted in the tip. You need to remember that the first caps were actually paper caps, and you might encounter cartridge that was designed for these, not for modern plastic caps.
Apart from older non-blowback designs this cartridge type is still used in revolvers and bolt-action rifles.
BLK (BLowbacK) - the first major revision of cartridge made it possible to operate blowback action, where part of pressure operated slide or bolt in semi- or full-auto action. Such cartridges are very similar to open type, single-piece tube, but instead of placing cap at the tip it is pushed deep into a single-piece shell. Cap is fired by a thick detonator pin that fills whole inside diameter, pressure acts between pin and bottom of cartridge for blowback effect. Bottom of the shell usually had a hole to aid in pushing out of a used cap, with a wedge-shaped insert normally covering it from inside.
These cartridges are used in older MGC models that have not been released again as CP-BLK type.
CP-BLK (Cap Piston BLowbacK) - the next major improvement by MGC. Multi-part cartrige now looks more like a real one, as the detonator pin (and corresponding hole in the cart) was made much thinner. Cartridge is made of two parts, top and bottom, screwed together. Cap sits at the very bottom, and a piston with pin is placed on top of it. Detonator pin (thin) now only strikes piston (thick, filling inside diameter). Early versions used an empty cap as a seal to ensure correct operation. Later "CP-BLK" cartridges seem to use normal o-rings, leading to a bit of confusion in naming with "CP-HW".
Typical for MGC modelguns.
CP-HW - slight modification of CP-BLK design, with silicone o-ring used as a seal instead of a cap, to ensure better operation.
This is probably the most popular design, found in most modern modelguns manufactured by MGC.
PFC (Plug Fire Cartridge) - as certain aspects of CP cartridge design were covered by patents, Marushin had to invent another way of doing things. PFC design places pin at the bottom of the cartridge, with an upside-down cap above it. Cap works at the same time as a seal. There is also another insert above the cartridge that serves as a piston. Detonator pin pushes piston together with cap onto the pin.
Later modifications added a silicone o-ring around the piston, and also made pin in the bottom removeable for easier cleaning.
PFC cartridges are used in all Marushin models.
Often "PFC" is synonymous with a cap-firing modelgun, regardless of actual cartrige type.
Hudson - design is very similar to CP-BLK and PFC, but with Hudson specific variations. Variation usually means a side hole in the top part of the cartridge, differently shaped piston pin. Special plastic rings were intially used for seals (instead of used cap in CP-BLK), later replaced by silicone o-rings (as in CP-HW).
Tanaka - wierd multi-piece design used in Tanaka modelguns. It is normal size, but instead of 7mm cap it uses 5mm, requiring additional internal parts to adapt smaller cap to larger internal diameter of a cartridge. Much more complicated than any other design.
KSC (revolver) - while revolvers with closed cylinder (metal) had integral firing pins mounted inside cylinder and could use open cartridges, other revolvers (ABS/HW) had open cylinders and required different cartridge design. Firing pin was integrated in this cartridge design from KSC, as a screw-on top part.
These cartridges are very popular in ABS/HW revolvers with open cylinders.
Proposed naming of cartridge parts:
- shell - when cartridge does not screw into two separate parts, the main part can be called "shell". This is typical for open and BLK cartridges.
- top and bottom - for cartridges that are made of two parts screwed together: CP, PFC and revolver. In revolver design top part has integral firing pin.
- insert - insert found at the bottom of cartridge (BLK, CP, Hudson), or rod going through center of the cartridge (revolver, open).
- piston - round metal insert that sits on top of cartridge in PFC design. Also any other such piece inside a cartridge.
- piston pin - metal insert integrated with small detonator pin, found in CP and Hudson cartridges.
- o-ring - silicone o-ring used to seal piston (CP/PFC/Hudson) or firing pin (PFC).
Note: I will work on pictures to illustrate that, time permitting.
Sat Jun 19, 2010 4:13 pm
Cartridge types and differing designs can be confusing without seeing actual examples but this, with the diagrams particularly, is excellent and really helpful
