B3 tune

[xschug3]

All of you B-3 owners out there, I've got a question regarding the potential power of a B-3 after a tune. I would like to know if anyone has replaced their spring and seal and gotten anywhere close to ~800fps? My B-3 is currently stock, but I would like to order a new spring and seal for it and attempt my first tune. I have no idea what it's shooting at now, probably between 550 and 600 fps but I would like to get it close to 800 or more if that's possible. So, what spring and seal should I use? Can I install a completely different spring in it such as one from a Gamo powerplant or is would this spring be too big?

Thanks for all the input in advance.

Trey

[JimL911]

I don't have one but this might be helpful.
http://webpages.charter.net/guru1/documents/index.html

[longislandhunter]

I've tuned all 3 of my B-3's and they all turned out very well.  In all of them I simply used the QF-2  cleaning/tune kit  you can get it several places including southsummit and I believe perhaps Archers.  The kit gives you a replacement spring that will fit no problem and that will give you more power.  It also contains a couple extra breech seals as well as a replacement synthetic seal.  If you're going to use the new synthetic seal, which fits just fine, you'll need a seal button or you can use the old 22 cent (2 dime & 2 pennies) trick where you simply put the coins together, drill out a hole in the center for the mounting screw and then use the coins as your button.  

In 2 of my B3's I reconditioned the stock leather seal and re-installed it with the new spring, raised the fps pretty good.  In the 3rd B3 I installed the synthetic seal using a button I purchased online and it gave much higher fps than the leather seal, pushing the fps up into the middle to high 700's depending on the pellet.

There was a time a while back when a bunch of us were tuning up our B3's..... do a search and you'll find a ton of helpful info......

Jeff

[lillysdad621]

my b3  in .177 shoots them at 720 fps... hometuned, same spring.

[shadow]

I have a collection of tuned B's and all are pushing 700+fps. As Jeff mentioned there was a B3 craze awhile back and there's a tone of info on tuning and mods for them. Ed

[xschug3]

Thanks guys! I've been searching and have found a wealth of information on here. This place is so resourceful! Jiml911, that link with the pictures was just what I needed. I havn't done a tune before so those pics are a great help and step by step instruction.

Trey

[cole5169]

I tuned a couple of mine with the QF-2 kit (one kit purchased from SouthSummit, the other from Compasseco).  I used the springs, the new breech seals, and the sear and sear-spring drop-ins (on one, the other is still wearing in the original sear).

I went ahead and kept the leather seals in.  They needed some work, but they came out fine after soaking in oil, squeezing out the excess, and roughing off the "carmelized" coating that they had with sandpaper.

Some of Jim Maccari's heavy tar on the springs quieted them both down a lot.  Both are smooth shooters now.

Other than a very little metal polishing (and a lot of cleaning...), I didn't do much to the piston or compression chamber.

My go-to B3 has a Beeman universal MB on a barrel chopped 6.5" shorter (and a correspondingly shortened cocking arm).  After recrowning the chopped barrel, the improvement in accuracy over the "as delivered" condition was amazing.  I really didn't expect to make it any better (it was, a frankly terrible shooter to begin with).  Now I can get better than 3/4 inch groups at 25 yards (5-shot).  
It shoots Gamo Match (.177) at 710fps with very little variation.  I keep meaning to bedliner the stock, but it actually is a nice, dark brown, and I can't bring myself to do it yet.