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Slavia · Moderator

Both Gamo and Crosman have come out with new piston designs. First, Crosman - here's Steve Upham, VP of Sales for Crosman:
http://www.youtube.com/watch?v=6qKvQRYDFKg
Crosman is employing a split piston with a flexible disk that locks the piston to the cylinder, preventing rearward rebound off the cushion of compressed air (1:04). He also claims range is increased by a factor of 2 (1:50). After playing with Chairgun I call BS on this one. Either they developed the piston in Area 51 with alien technology, or we need to re-open the discussion about what hallucinogens are in the Pellgun Oil formula. Since he is in sales, I can give him a break - if he worked for Industry Brand he would probably be telling me a B3 is good for Cape Buffalo.

Jeff Hanson, a Crosman ME involved in the development of the design, is more believable:
http://www.youtube.com/watch?v=voSn5EHUIkI
Some interesting points from his interview:

1. The new compression tube is larger (1:25).
2. The arresting disk is polyurethane (1:56).
3. The new piston is buttoned (2:03).
4. Crosman has achieved a 10 lb. reduction in cocking force (2:54).
5. The gas strut is rated for a minimum of 10,000 cycles (3:54).
6. The new trigger design is a "true two-stage" (4:12).
7: He claims a 35% increase in FPE (4:59).

Gamo has a new "turbo" piston design:
http://www.youtube.com/watch?v=vVivgxlnD_I
It appears to me to be simply an additional bearing surface that allows the metal coil spring to spin. (I couldn't find it offered with any of their gas strut/IGT guns.) The video shows the spring twisting on cocking at 0:32 and on discharge at 0:35. Not to say this is bad, because it would be one less thing to do on a tune.

Both of these designs raise questions about accuracy, power, cost/benefit, pellet selection, and retro-fitting older guns. How lubrication of the cylinder walls will work with Crosman's arresting disk is another question, as is the disk's durability

Does anyone have more information? Perhaps a different interpretation of the stuff that I'm looking at? More questions?

AirGunEric · Site Admin

I spoke with the engineer about this in a fair bit of detail at the SHOT Show a couple weeks back and looked over what I could (the piston and strut pieces, only the fully assembled rifle otherwise- no trigger block or such parts were available).

The tube is larger, thus more volume, thus the higher output. I did not bring up the screwy numbers being claimed as such claims are usually BS anyways- the real numbers will be available when people with chrony-in-hand test it. The buffered, or "arresting disk" thing is neither new or particular to Gamo or Crosman- at least one Norica rifle already has this.

The engineer readily admitted that the new trigger is better than the old unit found on the B18 and B22-platformed rifles, but not as good as the aftermarket units- there was not enough time from design, approval and production start to really do alot with the trigger. The quote, at least as I remember it was "it is a better design and has a 2-stage function" which might be able to be interpreted a couple ways.

Slavia · Moderator

Slavia · Moderator