problem found with 350's breach

[GoodOlRWS45]

Hey everybody, I hope all is well with my fellow members.  I've been gone for a couple of weeks, due to illness.  While I was down though I was looking at my new RWS 350 and found that my breach seal seemed to be a bit under the metal.  When looking from the side, I couldn't even see the seal.  On the opposing side (compression chamber port) there was lots of evidence of blow-by.  I compared it to my model 45 that has a new seal in it (the 350's seal is also new, as is the whole rifle) and it is quite a bit higher, and there is no evidence of blow-by on it's compression chamber port.  I've taken pics to illustrate my problem.  How do I go about fixing it?  I've heard of shimming the seal, but how is this done?

Thanks.

[melloroadman]

I bought shims for my 46 from Umarex .Marvin

[Gene_SC]

Jonathan, it does look like it is not sealing properly. Quick test is to lay a small piece of tissue accross beech block and then shoot. If tissue blows off then you have a problem. A good fix is by shimming, like Marvin wrote. I have had good luck by winding teflon tape around barrel bore and then push breech seal back in place. This is not an unusual problem and shimming is what you need to bring seal up.

Good luck and let us know what your fix was.

Gene

[GoodOlRWS45]

Is there a good way to remove the breach seal without damaging it?

[SDale]

Use the file from a set of nail clippers. That should get it out fairly easily without damaging it. You can Use dental floss, paper or that clear semi-hard plastic from a blister pack to shim the seal. I prefer the plastic. Did it on a couple guns and usually all it takes is one piece. Works like a charm!

[Gene_SC]

Also a scribe will lift the seal out very easily.

Gene

[vinceb]

Not an uncommon problem with Diana breakbarrels

http://www.pyramydair.com/blog/2008/04/shimming-diana-breech-seal.html

[longislandhunter]

I enjoyed reading that Vince,,,, very interesting.  I haven't shimmed any seals yet but now I know how  :)    Thanks.....

Jeff

[vinceb]

For shimming, the 90089A330 fiber washer from McMaster works nicely. They're about $10 per pack of 100 and can be used on a variety of guns.

The standard #109 Buna-N O-ring works nicely as a breech seal, they cost about $2 for 100.

[GoodOlRWS45]

Thanks guys...I popped out my breach seal and there was an aluminum shim under it already.  I tried using the hard plastic from a blister pack which helped, but I ended up using two of them to make it right.  So under my breach seal, there are three shims...one aluminum and two plastic.  the seal seems to stay in place with out any problems.  when I get a chance I will take the rifle out and see what a difference that made.  Thanks again!

[daveshoot]

Still seeing any ground squirrels up there, or are they going to bed yet?
This was an interesting thread. Hope you're feeling better.

[GoodOlRWS45]

Thanks, I am feeling better.  This morning I took a ride out to one of my hunting areas and didn't see a single squirrel.  I did see a couple cotton tails though.  Now that I have this breach seal thing figured out, I can't wait to see how many yards I gain.

[vinceb]

That's the best way of telling.

[GoodOlRWS45]

No, I don't have a chrony.  the only way I have to test is in the field.

[GoodOlRWS45]

WOW!!! What a difference!!!   After adding those shims, I took my rifle out and was amazed.  Not only did I get more power, but the rifle is much quieter.  Also at 40 yards my pellet is striking the target 7.5 inches higher then where it was zeroed.  I had to adjust my scope so my rifle would shoot lower.  The noise of the pellet going through the air is quite a bit louder too.  I have no Idea how much velocity I gained, but it seems huge.  I thought the rifle was powerful before...I can't wait to hunt with this baby!!!