Hi- new to the forum, and I have a question. Bought a RWS 350 Magnum over 10 yrs ago. Beautiful gun, fit & finish is great, well worth the money. When I bought it,, I chronied several weights and brands of pellets, and marked them all. I have shot this rifle off and on over the years, but with the ammo shortage I’ve really been practicing with it lately. Just for kicks, I thought I’d rechrony some of the pellets and find it is shooting around 100-130 FPS slower than when it was new! Do the springs get weak on springers, or maybe the piston seal going bad? Still shoots good just not quite as powerful as it used to be
RWS 350 Magnum
- Thread starter RWS-user
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Most likely deteriorated breach seal or piston seal. You can load it and place a tissue over the breach to see a puff if air may be leaking. If it is not the breach seal then I would just get a kit for the internals. Simple job once it's opened up. Better than new, and good for another 10 years!
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Vortek just came out with a High output and a Super High output kit for the 350. They also sell breech seals separately. If you left it cocked for a long period fo time it may be the spring. 10 plus years also may be the piston seal. Breech seal with slow it down some but only about 20-30 fps. Piston seal some as well, but 130fps if its a 22cal is the spring. .177cal, maybe not.
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Yes do inspect your breech seal and try a couple of drops of silicone chamber oil. Make sure it's the special silicone compression chamber oil and not be regular spring oil. I got some under the RWS brand. What I do is break the breach open just enough to get the needle into the transfer port to drop a couple of drops down there with the rifle oriented vertically. Then wait a few seconds and draw the barrel down to the cocked position to aspirate the oil into the Piston chamber.
You can keep your hand on the barrel and pull the trigger to release it then work the piston up and down by moving the barrel between almost closed and almost cocked to distribute the oil inside the chamber.
Good Luck
You can keep your hand on the barrel and pull the trigger to release it then work the piston up and down by moving the barrel between almost closed and almost cocked to distribute the oil inside the chamber.
Good Luck
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And when you originally ran your numbers the rifle was well broken in right? A little lube burning when new will increase fps. And/or it was lubed a bit heavy and that lube is thunk & hard now.
Personally still like JM esp. for lubes. Poke around he does have some 350 parts.
https://www.airrifleheadquarters.com/catalog/item/251485/43075.htm
What are you numbers?
John
Personally still like JM esp. for lubes. Poke around he does have some 350 parts.
https://www.airrifleheadquarters.com/catalog/item/251485/43075.htm
What are you numbers?
John
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A bad breech seal (actually the wrong one) on my FWB 124 caused me to lose 100 fps. The kleenex test mentioned sent the tissue flying two feet off the breech when fired. Try that test first. If the gun shot good before it's sitting awhile then I'm thinking piston seal is bad.
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Update! Took the RWS apart (first time) , broken main spring! Going to replace piston seal- it was looking a little ragged around the edges. Well, when I get the parts and get it put back together, I’ll run it through the crony again and see how it does. I’ll update
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Jon- RWS Superdome- was1015, now 935- (8.3gr)
Beeman Silver Arrow- was 830, now 715-(11.50gr)- took it apart and main spring is broken!
Beeman Silver Arrow- was 830, now 715-(11.50gr)- took it apart and main spring is broken!
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Make sure to debur the receiver tube slot edges and the 90 deg corners before reinstalling the piston. Don't want to knick the new seal.
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Jon- got my new spring and piston seal installed- had to make my own spring compressor and it worked. The new spring was over an inch longer than the old one! Put it over the chrony and the RWS superdomes are now at 1060-1070- a little faster than when the gun was new. Of course the cocking effort is also more.
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