STILL getting hammer bounce in 1720T

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STILL getting hammer bounce in 1720T

Postby Loki_762 » Thu Apr 27, 2017 9:49 am

I purchased a used Crosman 1720T about a month ago, and since then, I have not been able to stop the hammer from bouncing. Shortly after purchasing the gun, about 20 shots, the valve stem broke, and I had to replace it. I just bought an OEM replacement, nothing fancy. I put it into my gun, reassembled it, and the hammer has been bouncing ever since. I have tried the Bstaley mod with 3 o-rings and with 4 o-rings. No luck. I have put in a heavier hammer spring with the OEM valve spring. No luck. I have put in a heavier hammer spring with a heavier valve spring. No luck. I have done a heavier valve spring with the OEM hammer spring. No luck. I have adjusted the hammer tension and throw all over the place. But nothing has worked - once the gun gets under about 2700 psi, the hammer begins to bounce, and the closer I get to 2000 psi, the more it bounces. This isn't my first 1720, and when I did the BStaley mod before, it worked beautifully - after drilling out the TP to 3/32nds I was getting about 25 shots at 870 fps with Polymags, which is what I was hoping to get out of this one. I even set it at all of the same settings as my previous one. Needless to say, I am frustrated.

At this point, I am feeling like the only thing it could be is a problem with the valve. Maybe the valve stem isn't properly seating, and is allowing extra air to escape. Maybe there is a chip in the valve face that allows air to escape if there isn't enough pressure on the valve seal. I am considering chucking up a polishing bit in my Dremel and taking a go at the valve face, but I am not sure that is the best idea yet. I may also just need a new valve. I dunno. Do any of you out there in Airgun Land have any brilliant ideas that I may not have thought of?

Thanks in advance,
Posts: 65
Joined: Thu Jul 25, 2013 4:20 pm

Re: STILL getting hammer bounce in 1720T

Postby moorepower » Wed Oct 11, 2017 7:51 am

It is the nature of the beast. Call Travis for s tss. That will get rid of the majority of it.
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Joined: Mon Feb 24, 2014 5:14 pm

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