Getting My FWB 300 Shooting Again

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wijib

wijib

Member
Jul 8, 2020
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Leland, North Carolina, United States
I just started to disassemble my FWB 300 to give it a complete tune. It had never been apart since it was manufactured in Germany and the breech seal and buffer were the consistency of dried caulk. Everything was stuck/stiff to move including all the screws. I ran into a problem removing the guide pins for the sledge but I persevered. The first one came out a bit stubbornly but was fine . The second one came out in two pieces. So now I'm looking for a replacement. Anyone other have ideas as to how I should proceed/aquire a new guide pin?
 
 

https://www.feinwerkbau.de/en/Service-Download/Exploded-drawings
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I learned that the front guide pins are manufactured with different diameters. Geez...why do things always become complicated. I was lucky to have a micrometer so I could measure mine. 0.1573 " . Lucky too that Neil Stepp had one left with that diameter. I think he said that there were 4 or 5 different diameters on those little buggers. I'll bet it doesn't matter if they are a little small...do you really need the precision on those guide pins anyway? While I was at it I ordered new factory springs for it.


 
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Well, here's where I'm at so far: The FWB 300 is disassembled. Needed a new guide pin...Fuhrung Sache # 1700.013.1 (ordered one from Neal Stepp at International Shooter Services). While I was at it I also order a new spring set. Ordered new breech seal and buffer from J Maccari. Removed the old seal and buffer...was like prying out old window caulk. Cleaned and polished the outside of the compression tube and removed some superficial corrosion. Inside of the tube had some of the old buffer stuck to it so I gently cleaned it out and noted the surfaces in contact with the piston were in great shape. Piston was cleaned and polished. The piston ring is in excellent condition. Need to get some lube somewhere for moving parts. I will do some research as to how best I should lube everything.

I have read that the spring set from Jim Maccari (Arctic) may perform better than the factory springs. Any comments about that? 
 
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Maccari discontinued the Arctic spring for the 300s stating that it may give undue wear and stress to the gun. I haven't installed them and just bought several just because he was no longer going to make any more.

I would install one if I came across a beater for cheap that needed a replacement spring though.

If You purchased yours as a collector then I would suggest restoring it as close as possible to factory specs using modern day improved time and wear friendly parts.
 
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The hottest I've ever had one shooting with drop in parts was around 670fps with 7.3gr pellets. A stock spring setup is like 630-640fps usually. 

Not enough difference to matter really. But the Maccari spring does have more recoil. You can tell by how much the sled moves around. 

Run the factory dual springs if you got em in my opinion. 
 
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I think the Arctic spring is supposed to produce higher velocity than the factory springs. Don't know if that's necessarily better, or how much more, though. I've got one of JM's springs, but haven't tried it yet.
Click to expand...

Maccari discontinued the Arctic spring for the 300s stating that it may give undue wear and stress to the gun. I haven't installed them and just bought several just because he was no longer going to make any more.

I would install one if I came across a beater for cheap that needed a replacement spring though.

If You purchased yours as a collector then I would suggest restoring it as close as possible to factory specs using modern day improved time and wear friendly parts.
Click to expand...

The hottest I've ever had one shooting with drop in parts was around 670fps with 7.3gr pellets. A stock spring setup is like 630-640fps usually. 

Not enough difference to matter really. But the Maccari spring does have more recoil. You can tell by how much the sled moves around. 

Run the factory dual springs if you got em in my opinion.
Click to expand...

Thanks guys for your willingness to share your experiences with me. I've been around a long time but I am always learning new stuff.
 
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