I have two 760s. In both cases the bolt leaked air badly. I did solve the leak problem by making new bolts. The original bolts are .186 dia. They are way too loose. I made mine out of steel and made them .192 dia .This made a good seal and still moved smoothly. Gained 50fps at full power with BBs. No air blowing back at you either. n.h.schmidt[/qouote]I did make an extension for the original brass bolt. Cut the magnet off and drilled and tapped the end of the bolt. Added a brass extension about the same diameter as you used. Wanted to keep the brass bolt to look original.Don't want to use bb's, but do want a rifled barrel. Just need to find out what would be the best barrel to start with.Maybe a 1760 or ?
Just picked up an nice clean Crosman 760 1st variant for $5.00 at the local flea market. Just needed resealing, made a new aluminum o-ring piston for it but stock other wise. Now this is a self cocker so uses a different barrel than the newer models.What I need is some advise on machining a new rifled barrel. What Crosman barrel is best to use? Any tips on sealing the bolt to barrel (no seal on original). No problem on doing crowns and leads as I have a lathe and mill.If anyone has done one before, any info would be appreciated.
The barrels for the newer 760's are different than the old style self cockers. Think maybe a 1760 will work with some machining.
Quote from: Robert Skelton on April 30, 2017, 08:24:22 PMThe barrels for the newer 760's are different than the old style self cockers. Think maybe a 1760 will work with some machining. I know there are experts on this board who can help you with this, eventually they'll show. I dont own a 1st variant. I was never lucky enough to get one for $5. So, I don't know the internals.I HAVE modded a few of my airguns. So, I've run into some issues which you may have.You may just need a .177 barrel with the same Outer Diameter as the stock barrel. You probably can cut and choose what ever length you want. 1760 would be the longest barrel in .177, if I'm not missing something.I'm not sure if the 1st 760 had a transfer port drilled into it, but that would be one measurement to look out for. Also make a smooth lead-in and you mentioned the crown already.If you can, try and take pics. I enjoy seeing other people's work.
Got a chance to work on the 760 this week. Changed the red dot to my old 70's Weaver K 2 1/2 power. Also milled some off the mount to clear the receiver and moved it back 1 1/2". Finally found a pellet it liked, Air Arms 8.4's. Getting 1/4" at 10 yds and 1" at 30 yds. No chrony test yet.Made another scope mount like the one on the 760, tried it on my Crosman 100 but like any scope on those style of rifles it raises the scope to high to be practical. Hard to believe how much time it takes to make one.