None really, the new delrin ones are light as hell!
Anyone who says these are heavy is high, because not onnly are they light as hell but now you can up your cocking pressure to make it faster that will more than compensate for any measly 10 gram difference in weight! these guys were so cool, they couldn't ship immediately so they shipped express at no extra charge! and they were super helpful! the best part for cockers ever made with awsome customer service for a super reasonable prices! what else could you ask for
I don't use drugs but i still think 44 grams is heavier than it needs to be.
I have a V1 delrin jam bolt which weighs the same as an orracle bolt on my home made balance scale. the orracle bolt is 63 grams. This is mostly due to there being a large chunk of brass inside the V1 JAM bolt by the inlet hole. plastic would have made a much better plug. it looks from the pictures like he switched to aluminum in the V2 JAM bolt. again plastic would be better and shave away some or drill holes on the sides. all that is needed is enough material for strength, allignment and to guide the travel of the spring assembly.
the shocktech supafly is somewhere around 44 grams and I own 2 of those.
Orange claims 22 grams but is really 23.
Slik edge V3 Nylatron is 15.5 grams and appears to be plenty strong enough. that is hitting paint with a lighter weight and a lower cocking pressure. I think that could be at least as effective as a jam bolt and make your gun cycle alot faster.
faster cycling means it is harder to short stroke because the bolt goes all the way back the instant you touch the trigger. Lighter weight means lower pressure and less total force hitting. I can get pinches with my superfly and stock ram on my lowest mech cocker. I played for about a year and a half with it with only one chop and that was due to my timing being affected by an empty tank. I sometimes shot fast enough that little kids though i was using full auto (on my hinge frame) so I think you can do better with light weight than a spring.
I like the jam bolt, I own one, i just think that it could be a lot lighter than it is and that would radically improve total performance.