I have the Cock on Open mod on my QB 79. Installed it about a year ago and think it's a worthwhile improvement( for me at least). The only thing that takes a little practice is loading the pellet in the smaller space you have in the loading tray. After time it comes naturally just like when I first got my TX200 which was also a pain to load in the beginning. I find my TM1000 harder to load than the QB.All these other bad characteristics you said the one you shot had, mine does not. When I put the bolt back it stays there until I push it back and lock it. Mine does not have a rear slot that the bolt handle goes into, only a front slot. Maybe the kit was not installed correctly? I'm sure someone with more knowledge that me on this subject this will chime in.
OK, When I pull the bolt back and cock the gun, I hear the "Click" at the very rear on the bolt handle stroke... yet if I release my rearward tension on the bolt handle, it will move halfway forward with the force of what I have to assume is the hammer spring. (It is VERY strong).
ok, it has now been explained to me that mine does NOT have the hammer pin drilled and relocated. The reason is, since this build has always been focused on maximum buildable power, the hammer will have more stroke this way, and therefore allowing for less spring tension and easier cocking. OK so now that makes sense to me as to WHY it was done this way, and I will just have to become accustomed to locking it back in the rear slot to load the pellet. I will probably touch up the rear slot just a hair to create a minimal "hook" like Bob's, to help prevent the accidental slamming shut. I need to get this done so that it can go to it's rightful owner.THANK YOU ALL, for all your help.
Quote from: tri-5-ron on December 21, 2015, 05:56:22 PMok, it has now been explained to me that mine does NOT have the hammer pin drilled and relocated. The reason is, since this build has always been focused on maximum buildable power, the hammer will have more stroke this way, and therefore allowing for less spring tension and easier cocking. OK so now that makes sense to me as to WHY it was done this way, and I will just have to become accustomed to locking it back in the rear slot to load the pellet. I will probably touch up the rear slot just a hair to create a minimal "hook" like Bob's, to help prevent the accidental slamming shut. I need to get this done so that it can go to it's rightful owner.THANK YOU ALL, for all your help.I can't quite get my head around this one. My hammer "hooks up" on the sear in the exact same spot as it did when the pin was in original spot. Only thing that changes is the position of the bolt. How do you get more travel?Here is my hammer
Quote from: BigTinBoat on December 21, 2015, 08:09:58 PMQuote from: tri-5-ron on December 21, 2015, 05:56:22 PMok, it has now been explained to me that mine does NOT have the hammer pin drilled and relocated. The reason is, since this build has always been focused on maximum buildable power, the hammer will have more stroke this way, and therefore allowing for less spring tension and easier cocking. OK so now that makes sense to me as to WHY it was done this way, and I will just have to become accustomed to locking it back in the rear slot to load the pellet. I will probably touch up the rear slot just a hair to create a minimal "hook" like Bob's, to help prevent the accidental slamming shut. I need to get this done so that it can go to it's rightful owner.THANK YOU ALL, for all your help.I can't quite get my head around this one. My hammer "hooks up" on the sear in the exact same spot as it did when the pin was in original spot. Only thing that changes is the position of the bolt. How do you get more travel?Here is my hammerRob,here's how it was explained to me....For the cock-on-open, at this power level, (max),it is necessary to have a good amount of spring preload. At the stock power level, the cock-on-close action is just barely tolerable. With the preload increased, it can actually hurt the ball of your hand when pushing it closed. A couple more benefits(with having the Cock on Open mod) is that it provides more hammer travel which is a good thing, otherwise it must be compensated with even more spring preload. Another benefit is that it allows (the shooter) to feel any problems with a poorly fitting pellet. Drilling the hammer and relocating the cocking pin gives some space to insert a pellet without putting the bolt into the rear slot. Latching the bolt fully back gives a nice wide berth for dropping in a pellet.
ok, it has now been explained to me that mine does NOT have the hammer pin drilled and relocated. The reason is, since this build has always been focused on maximum buildable power, the hammer will have more stroke this way, and therefore allowing for less spring tension and easier cocking.[/quote
The only way to change the hammer stroke is to change the relationship between the ring where the sear latches and the front (striking face) of the hammer.... If you reduce the distance, you will get a longer stroke.... You can also shorten the valve stem, or drill a recess in the front of the hammer, but doing so the hammer may then hit the backing block and not open the valve as far....As soon as you change to "cock on open", once you have cocked the gun (with any preload), the ring on the hammer where the sear catches rests against the sear in the trigger.... This causes the pin to push the bolt part way closed.... Moving the pin back in the hammer repositions the bolt further aft, relative to the hammer, and hence there is more room to load a pellet.... I have never tried that, because I was usually looking for more hammer travel, using a custom hammer as in the photo below....The stock hammer and cocking block are on top.... the custom ones are on the bottom.... Note on the hammer the reduced length between the front of the hammer (near the hole) and the front of the ring where the sear engages.... That increases the hammer stroke (when cocked, the front of the hammer is further from the end of the valve stem).... However, since the hammer moves further back you have to remove the boss on the back of the hammer because it will hit the cocking block.... Once you shorten the back of the hammer, then the pin (spring guide) on the cocking block can then hit the inside of the hole in the hammer, and it still won't cock.... so that must be shortened as well....Although I no longer have this particular QB, it would appear that if I used the lower hammer and cocking block, and also moved the cocking pin back on the hammer, I might not need the rear downward slot.... The caveat is that with the hammer latching onto the sear further back, if you also move the pin, you MIGHT end up in the situation of not being able to pull the bolt back far enough to clear the rolling sear on the trigger.... ie you couldn't cock the gun!.... It MAY be possible to cut the slot for the bolt handle further back.... or maybe not, the bolt may hit something else.... That is the fun of modding, one change means two more, and those two mean four more.... etc.etc.... Bob