FWB Speed Boost Steps

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JoeWayneRhea

JoeWayneRhea

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Apr 5, 2015
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So I'm shooting my FWB with my buddy Murphy 59 and I am pleased to see my guns velocity has gone up after changing out the piston buffer and breech seal and replaced piston O-ring and stripped lube and put in a new stronger spring , here's how it worked out
1. Rifle before was 605 fps before any updates
2. replaced breech seal and gained 5 fps ( evidently seal was good before ) 610fps
3. replaced piston buffer and gained more ..620 fps
4. replaced O-ring and gained another 15 fps .635 fps
5. replaced original dual spring set with a new Macarri spring. 655fps
6. I stripped gun down yet again and wiped every single trace of lube from the piston and compression chamber . 685 fps !!! That's a 80fps boost . Which may not sound like much but it's almost a 15% boost . AZ , Pete B. , GoodtoGoand Jonnes among others have finally got it beat into my hard head that a dry piston and chamber is the way to go .
If I couldn't strip one of these down before , I dang sure can after today :) It was worth it to see how all the little stuff would affect fps . I'll update in a week or so and see where velocity is after it all breaks in . PS all shooting was done with JSB 7.33 pellets .

Here's a video about it .
 
Nice work Joe. I need to order a few seals to keep on a shelf.

AG72 it helps to have a few picks that have the right angle bend for the small e-clips or c-clips. I also lay a large magnet on my table and lay a small screwdriver on it. It just helps to pick up the clips and get them close to where they go. And watch Joe's videos and be sure you have a small punch to use when you are removing the spring. It is just to take the pressure off the spring. The FWB300 does not have much preload on the spring. It takes me about 30 mins to lay it all out and get it back together lol. My tx200 takes about 10 mins to take apart and get back together.
 
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AG this is a shot from video showing how to remove the tension , just use a punch or something round and you can wiggle it back an forth so there is no tension on the nut . But if you are truly worried it may not go back together because threads are already messed up then I'd probably just leave it be until it needs to be taken apart . Good part is that the nut that holds it together is still available so you can pick up a replacement
 
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Today i was planning to have some nice winter shooting with my fwb, but there was something wrong, the first shots sounded like they where realy fast, then the velocity droped and then realy fast again, and the accurasy was gone, some high and then to the right and low,and could smell something burned, she was dieseling, shot a couple moore but they droped like 2 inches so gave up, took here apart and there was oil on the buffer, wiped her bonedry and changed the sealing so hopefuly the problem is solved
 
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So today i went out again to see if she had improved, but no, about 3-5 shots in the same hole at 25 m, then abit low or to the right or left, but in the same hole, had about 30 rws superdomes left in the can, when they where finished i opened a new batch and they went in alot easier, so i hade to start over again, but the result was the same, tight groups for a handfull and then it whent away, shot trough the chrony and speed was between 160-170 m/s for 10 shots, about 8 joule, so no improvement there, but then i saw something: the rear scopemount was not atatched to the gun, it was loose hanging! So fixed that and shot 10 in the same hole! But could not continue cause it got dark and the wind started to get bad, but hopefuly the problem is solved... Please sun comeback, I need you!
 
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