Stopping Spring Guide for a Crosman 2240

[WobblyHand]

Been toying with this the past day or two. An SSG is used to reduce hammer bounce in air guns. This can in turn reduce gas or air usage and usually results in lower extreme spread of velocity in shot strings. Not my invention, but merely my bumbling version, machining nearly everything from raw materials.
Design concept

Made a couple of changes - some due to my screw ups, some because I thought the ordinary nuts were ugly. So I knurled some stainless instead.

The report is shorter using the SSG, indicating lower gas consumption. (Shorter dwell time.) The 2240 is a CO2 single shot air gun. Bought it on sale new for $45. The rod is adjusted so it does not touch the hammer when at the hammer's maximum distance. Single pointed the threads, save for the 3/8-24 cap. Used a tap there. Should have single pointed them, as the tap ran large. Had to remake the adjuster screw (3/80-24 threads) because the tap size ran large. The adjuster screw was made from hex stock, turned to 3/8, single pointed, then drilled and reamed to 3/16" Then the bottom was bored to 0.280" diameter, 0.250" deep for the spring. Was a fun little project on the lathe.

Might make a different version of this, maybe something to cover up the nuts. They could be somewhat of a hazard to someone not paying attention. This is when the air gun is cocked.

 

[Ischgl99]

Nice project and explanation. I have an HW95 springer and I’ve been looking into getting a PCP rifle and saw people talking about SSGs, but didn’t really understand how they worked, this helped a lot, thank you.

 

[OTmachine]

Nice work! Was tempted to get one of those so we could have some competition shooting at the house, ( have a CR150 also). Along with a few(?) other air guns. You probably already know that taps come in different thread limits, GH -1 to 4 and GL-1 to 4 being the most common.

 

[WobblyHand]

Nice work! Was tempted to get one of those so we could have some competition shooting at the house, ( have a CR150 also). Along with a few(?) other air guns. You probably already know that taps come in different thread limits, GH -1 to 4 and GL-1 to 4 being the most common.

Thanks. I knew there were different limits, but was I paying attention when I bought my tap? Apparently not. I have a few 3/8-24 taps, probably ought to check their sizes, just grabbed the first one. Maybe even mark the tube!

Made some aluminum nuts this morning, just to see if I could. They were knurled on my mini-lathe only because I don't have a scissors knurler for my 10x22. Fiddled around getting them thinner, mostly for the aesthetics. Managed to get them to be about 0.150" thick, which was fun. I started out on my mini-lathe using a 1/2" ER-32 collet on the rod and knurled the 6061. I then brought the rod to my 10*22 and drilled and tapped to 10-32. Then chamfered the edges and parted off the pieces. I then switched to a 13mm collet to hold the pieces by the knurl. I used the excess knurled rod to fill the collet and pushed in the 0.150" nut to square it and face off the parting nubbin. Surprisingly worked quite well.

The bark is considerably toned down by the SSG, since the dwell is shorter. Actually that is how one sets it up. Loosen the adjuster so that the spring guide is no longer touching the hammer in the uncocked position. The hammer free flies to hit the valve stem and bounces back. The hammer then does work compressing the spring and friction loss. The hammer doesn't have enough energy to rebound and reactivate the valve. The sound is reduced enough that one can fire indoors.

This was a fun little project that worked out well.