Crosman 760 New-ish Style Bolt Blowing Open

[imadunatic]

Are there any known tricks for keeping these bolts shut? I know there are some hot rodders out there and it seems the consensus is to add an o-ring to the bolt or the barrel, the issue I have is that this particular gun hails from 2000 or so and has the plastic transfer block instead of the older cast style.

I'd like to still be able to shoot BB's if possible as this was built as a sort of gallery gun for the kids, but the bolt blowing open is currently a no-go. It should also be said that this was converted to CO2 and in stock tune it was BLASTING CO2 from every orifice when you fired it. I milled the spring pocket in the hammer about .500" deeper which lightened it ~5 grams and then I cut 3 full coils off the hammer spring before it finally settled down the point that it was somewhat efficient. I think this has exacerbated problem because the hammer spring now has negative preload and I think on a stock gun the hammer preload helps to keep the bolt shut.

I wouldn't be opposed to putting a SSG in this gun, but honestly it's just not worth it, efficiency wise, for a pop bottle cutter running off a 24oz bottle (plus anyone familiar with this gun knows there is a screw running right through the back spring guide, no place for a SSG to live without it riding with the hammer, though this may be my only option)

I'm happy with the performance for what it is, now if I can just get the bolt to seal/stay closed I'd probably stop tinkering with it and let the kids have at it. It's very fun to shoot.

Any help is greatly appreciated.

[Dave180]

I'm not impressed with the crosman bolts either.   They have it on all their guns that have a sliding bolt.  I'm sure a metal receiver would help but probably not much.  Did you try the piece of rubber wedged into the bolt trick?  It helps a little.   

[imadunatic]

Did you try the piece of rubber wedged into the bolt trick?  It helps a little.

I haven't tried it yet, was just reading through the other thread on the Model 66 and noticed that. If I was more perceptive I would have just followed that conversation instead of starting my own... 

Do you just use a chunk of hose? I'm very tempted to just machine a new aluminum carrier/bolt similar to the old pivot style, but I'm really hoping to just improve upon the current design rather than start over, especially on this gun. There is so many of us that have this problem it would be a nice one to solve.

[plinker99]

what i found is the little tab inside the receiver gets worn & the bolt no longer stays latched.  using a soldering iron & some plastic i had,  i reformed the tab.

here's a link to a post i did awhile back. http://www.gatewaytoairguns.org/GTA/index.php?topic=40631.msg459691#msg459691

hope that helps.

while i'm at it, here's a link to a trigger mod i posted . http://www.gatewaytoairguns.org/GTA/index.php?topic=65696.msg625723#msg625723

[imadunatic]

what i found is the little tab inside the receiver gets worn & the bolt no longer stays latched.  using a soldering iron & some plastic i had,  i reformed the tab.

here's a link to a post i did awhile back. http://www.gatewaytoairguns.org/GTA/index.php?topic=40631.msg459691#msg459691

hope that helps.

while i'm at it, here's a link to a trigger mod i posted . http://www.gatewaytoairguns.org/GTA/index.php?topic=65696.msg625723#msg625723

Plinker, did you use plastic welding rod or another material to build that area up? I do have access to a plastic welder, but that might be overkill, plus using the soldering iron at home would be more convenient.

[plinker99]

l just used a plastic that look like a similar material that i had.  in my previous work, we had a panel that was often thrown away.  i saved some & it came in handy.  i thought of using the back end of he bolt since it looked like there is a section that can be spared.  after building up the tab,  some filing & sanding to make sure the bolt latches with no front to back play is needed.