Both breeches operate the same way. The brass in the plunger tube slides snugly into the larger brass in the barrel extension. When you close the breech, the plunger brass slides into the barrel brass and makes a seal.
The difference is that Jay cut a tongue into the plunger brass and Walcom didn't. Otherwise, the mods are identical.
The tongue guides the plunger brass into the barrel brass, preventing it from misaligning and jamming open. It also provides a smooth guide rail to help you slide the dart into loaded position. Otherwise, it shouldn't affect performance or functionality.
The drawback of Jay's mod is that it's difficult to cut a good tongue into brass. Ideally, you'd use a bandsaw or a bench-mounted Dremel and vise so you can cut an even, symmetrical tongue. The cleanup is also tricky - you need to round off the sharp brass edges and carefully bend it back into shape.
The downside of Walcom's mod is that it's marginally harder to load the blaster. Also, if something flexes or shifts, the brass pieces can misalign, and instead of closing and sealing, the plunger brass will push the barrel brass out of the blaster and bend out of shape.
Zack The Mack,
thank you for replying. ok but Walcom's is flush up agents the brass breech and the receiving piece of brass goes into the breach and in Jay's the piece of brass in the breach has a bit sticking out and that goes into the receiving piece. so that doesn't make a difference ? and this would be my 1st breach mod what one would YOU recommend ?
Ang Jay also mentions 1/2 inch brass, why is this and is it better to use 1/2 inch brass instead of the 17/32 inch brass ?