Choosing an Airsoft Shotgun: Spring, Gas, CO2 and Shell Systems

The word “shotgun” does not identify one airsoft operating system. A spring CA870, a gas M870, a GBB Saiga and a CO2 shell-ejecting CAM870 use different magazines, loading methods and consumables.

Compare the operating system first

• Spring: manual operation for each shot, with no gas or battery.
• Gas pump-action: gas is stored in the replica or a removable reservoir while BBs may feed from shells or a magazine-like holder.
• GBB: gas operates a cycling action, as on the Tokyo Marui Saiga family.
• CO2 and shell-ejecting: the shell design, generation and charging method are part of the system and must be matched exactly.

Spring shotguns

Spring operation keeps the power source simple, but capacity, hop-up, number of BBs released and loading method still vary by model. A Maruzen CA870 does not become compatible with another M870-pattern shell merely because both resemble pump-action shotguns. Check whether the listing uses a magazine, fixed loading route or removable shells.

Gas and GBB shotguns

A gas M870-style pump and a GBB Saiga provide different handling. Check where gas is stored, how BBs feed, whether the action cycles automatically, and what is included. Temperature and repeated firing can affect gas operation; do not compensate for a fault with a higher-pressure gas unless the exact manual permits it.

CO2 and shell-ejecting systems

APS CAM870 generations, Striker-12 systems and Maruzen/Tokyo Marui designs must not be mixed by appearance. Match the manufacturer, exact version, shell reference, wad or seal requirements and charging method. A spare shell product is not evidence that it fits every replica bearing an M870 name.

Checklist before choosing

1. Manufacturer, model and generation.
2. Spring, gas, GBB or CO2 operation.
3. Magazine or shell reference and stated capacity.
4. Items included with the replica.
5. Current availability of the correct shells, magazines and consumables.

For detailed cartridge questions, use the CAM870 and M870 shell compatibility guide. Browse the airsoft shotgun collection for current listings.