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Beeman P17 Mods & Issues
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Author:  Chrissstiaan [ Mon Jun 27, 2016 12:15 am ]
Post subject:  Beeman P17 Mods & Issues

Hey there, I have recently really wanted to mod my Beeman P17 pistol as I am always looking for ways to improve anything and I enjoy little things like that to work on. I've never done any mods before is there anything I should know or be aware of before starting? I'd like to do the air mod and make the piston a bit longer for higher compression & power.

If anyone here has any experience or tips please let me know!

Attachments:
File comment: This is the piston inside the pistol.
mod.JPG
mod.JPG [ 195.76 KiB | Viewed 6728 times ]

Author:  Plasticman [ Wed Jun 29, 2016 5:28 pm ]
Post subject:  Re: Beeman P17 Mods & Issues

I built up the piston with a bit of JBweld and it gave me a small increase in FPS.
It is a great little indoor gun and mine has over 2000 pellets shot'
It still works great.I cleaned up all the rough edges inside when I first got it. Had a bit of trouble with one of the trigger springs and just a bit of bending cured the problem. It has worked great ever since.

Author:  Chrissstiaan [ Fri Jul 01, 2016 1:46 pm ]
Post subject:  Re: Beeman P17 Mods & Issues

Plasticman wrote:
I built up the piston with a bit of JBweld and it gave me a small increase in FPS.
It is a great little indoor gun and mine has over 2000 pellets shot'
It still works great.I cleaned up all the rough edges inside when I first got it. Had a bit of trouble with one of the trigger springs and just a bit of bending cured the problem. It has worked great ever since.


Interesting, so far mine hasn't been modified or anything it's in out of box condition basically. I've put through about 800 or so pellets, I expect that to go up a lot this summer when I can shoot everyday.

Author:  offroad720 [ Sat Jul 02, 2016 5:56 pm ]
Post subject:  Re: Beeman P17 Mods & Issues

For hanging out with friends, I put a .22 barrel in my P17. It gives them a more notable damage to pop cans. I am using a HW45 in .22 cal and it was still affordable to run .22 RWS hobby in both. I am in the market for a chrony but with Canada Post talking about the strike, I will wait. I'm sure the FPS is low, but wouldn't mind doing other mods in the future..

Author:  hytong [ Sun Jul 03, 2016 8:54 am ]
Post subject:  Re: Beeman P17 Mods & Issues

check the air intake port edges inside the cylinder and smooth it out with abrasive, if there are rough edges it will start cutting your o-ring every stroke, below video shows it, a little bit of silicon lube e.g. molycote 111 should work well

https://youtu.be/BkGDRuHB-XY?t=4m25s

this brings to the question:
anyone has a good source to buy replacement O-ring seals?

Author:  twister [ Sun Jul 03, 2016 9:00 am ]
Post subject:  Re: Beeman P17 Mods & Issues

hytong wrote:
check the air intake port edges inside the cylinder and smooth it out with abrasive, if there are rough edges it will start cutting your o-ring every stroke, below video shows it, a little bit of silicon lube e.g. molycote 111 should work well

https://youtu.be/BkGDRuHB-XY?t=4m25s

this brings to the question:
anyone has a good source to buy replacement O-ring seals?

http://scopesandammo.com/storefront/pro ... -kit-p-739

Author:  Chevota [ Sun Jul 03, 2016 12:25 pm ]
Post subject:  Re: Beeman P17 Mods & Issues

Below are what I measured in my gun:
Valve, small .075 x .100" actual size = ~ -005
Valve, large .075 x .185" actual size = ~ -008
Breech seal .072 x .185" actual size = ~ -008
Piston seal .100 x .798" actial size = ~ -117

the -# is the AS568 (Standard USA) you should get, which is ID and sectional thickness.
So for the piston you'd want an AS568-117. Many places list fractional dimensions, so it might say 13/16 x 3/32, which is not really accurate but the closest fraction that's easy to understand.
So a -117 is supposed to be, per the spec, .798"ID x .103", and thus OD would be ~1.004". They usually are not the dimensions they're supposed to be, but close enough, which is why the actual I measured above is not exactly what AS568 lists.
On my gun the the tubes ID is ~.985", piston groove is ~.813 x .103.
Also, the guns dimensions may vary a bit, so between that and O-rings varying you might consider buying a couple -009's for the valve and breech since a true -008 is .176 and -009 is .208 and see which works better.

Also, there was mention of bending a spring to avoid hanging up the sears, but what I do is debur the sears and hammer. You can see where the springs contact the parts so that's where the need to be deburred, but I deburr everything and add a bevel in those key areas to be sure the springs are free to move.
There is also a wire inside the trigger that acts a guide which a sear passes thru, and if that's a tight fit you need to sand the wires a bit. The sears contact points can be smoothed and sharpened if you like.
Plus the mods in the pix:

Attachments:
Trigger screw mod.jpg
Trigger screw mod.jpg [ 59.88 KiB | Viewed 6475 times ]
Intake port.JPG
Intake port.JPG [ 78.43 KiB | Viewed 6475 times ]

Author:  Chevota [ Sun Jul 03, 2016 12:27 pm ]
Post subject:  Re: Beeman P17 Mods & Issues

.....

Attachments:
Optional Black.JPG
Optional Black.JPG [ 61.73 KiB | Viewed 6475 times ]
2 cocked and modded.JPG
2 cocked and modded.JPG [ 76.44 KiB | Viewed 6475 times ]
Valve.jpg
Valve.jpg [ 45.92 KiB | Viewed 6475 times ]

Author:  Chevota [ Sun Jul 03, 2016 12:46 pm ]
Post subject:  Re: Beeman P17 Mods & Issues

And for the piston, people have tried different ways to bump pressure, but this is what I did.
I think the rod in the piston is threaded in, if so then simply unthreading it to the perfect length would
be ideal, but it's in there tight as hell so I've been trying to figure out how to unscrew it w/o damaging it
cosmetically. Not a big deal to most if it has vice and vice grip marks on it, but it would bug me bad.

Attachments:
Piston shim.JPG
Piston shim.JPG [ 114.93 KiB | Viewed 6474 times ]

Author:  paddyfritz [ Wed Jul 06, 2016 6:32 am ]
Post subject:  Re: Beeman P17 Mods & Issues

They can be made multi stroke.

Author:  longhunter [ Tue Jul 19, 2016 7:30 am ]
Post subject:  Re: Beeman P17 Mods & Issues

I used aluminum repair tape on the face of the piston to bump the pressure. it needed 5 layers to bring it up to the face of the chamber. put it on one layer at a time, and trim with a razor blade. it now gets 430 fps, with an extreme spread of 2 fps. not bad considering that it was only doing about 390, when I got it. I also used a metal epoxy to bed the barrel in the frame. it stiffens up the top frame, and helped the accuracy, with the scope mounted. before I did that, I couldn't keep poi. I think there was too much flex in the frame.

Author:  Chevota [ Tue Jul 19, 2016 7:55 pm ]
Post subject:  Re: Beeman P17 Mods & Issues

Did you post pix of that metal tape and epoxy bed somewhere? I ask because I swiped some pix just like that from somewhere online.
Did you measure how much metal tape you added, or know the thickness of one layer? No doubt each gun is different but I'm curious since 5 sheets seems like a lot. Was that to just kiss the chamber with no air pressure? Mine kissed with .010, but I added 10 more as described in the previous pix.
What pellet/weight was the velocity measured with?
Out of the box mine was:
8.26 = 396
10.34 = 355
13.43 = 319
Haven't checked since mod but will post.

Author:  DerekVinyard [ Tue Jul 19, 2016 9:36 pm ]
Post subject:  Re: Beeman P17 Mods & Issues

P17 repairs? Just o-rings, a little oil and if you are eager a little deburring / polishing.

Best bang for the buck short range ever...

Author:  thumper [ Sat Jul 23, 2016 8:13 pm ]
Post subject:  Re: Beeman P17 Mods & Issues

...I read a post online where a second 'o' ring was added to the piston , and the piston shaft was removed and threads added so it could be adjusted with a locknut for piston depth......You have to keep in mind the strain on the cocking parts as you raise pressure......

Author:  thumper [ Sat Jul 23, 2016 11:56 pm ]
Post subject:  Re: Beeman P17 Mods & Issues

...If you google "Beeman P17 mods", then hit "images".....the second down on the right is a double 'o' ring mod from 'another airgun blog' .......The fourth down on the left is another double 'o' ring mod with the threaded adjustable piston rod ...... sorry, I cannot forward 'links' ( only provide directions.....old school)

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