B3-1 Tuning

[rr_shooter]

I'm taking apart my first B3 and starting on the trigger.  It's somewhat difficult for me to visualize the operation of the trigger because of the stamped housing.  Does anyone know of a diagram that shows the engagement of the sear with the piston and the contact surfaces between the trigger and the sear?  Or, maybe just a figure that shows which surfaces need to be polished in order to smooth the trigger operation?

Thanks in advance for the help!

[longislandhunter]

Here ya go............

Jeff

[rr_shooter]

Excellent - that's just what I needed. I'm always amazed at the depth of knowledge of this forum's members (and their desire to help out others).

Thanks, Jeff!

[longislandhunter]

Glad I could help Paul....  

I tuned the 3 B-3's I own,,, they came out great.  There's a ton of tuning info available for them, just do a search and you'll be amazed at the info you'll find.  I'll be looking forward to your future posts on that shooter....  Keep us up to date.....  

Jeff

[don_centex]

Hey Jeff,
What does polishing those trigger locations with 600 grit sandpaper help?  Does it make the trigger action more smooth and repeatable?

You've probably mentioned this before, but are you using the oem spring or some other custom version?  I'm getting ready to order a  spring from Mcari for my broken TF97 so I'm considering one for my B3 also so I was thinking he might have a good alternative for the B3 too.

I agree this is a great BB.  Lots of helpful information and people don't  seem to get their knickers in a knot over silly things.

tight groups!

Don

[shadow]

Smoothing the contact points of the trigger and sear give's a smoother and more predictable pull. There's a B3,B4 kit that comes with a replacement mainspring which is a nice replacement for the B3. South Summit in our MALL still carries them I think. Ed

[don_centex]

Is the spring in that kit any better?  Stronger, longer, easier to cock, anything like that or is just a replacement for one breaking?

Don

[shadow]

Basically the same spring a little longer which gives a little more punch. The cocking is about the same too other then the smooth cocking of a tuned one verses a box stock one. Ed

[don_centex]

OK, tks for feedback.  I'll keep that in mind.

Well, now that I have a broken TF97 spring that broke near the end I may have a suitable replacement that gives a similar ammount of more punch.  I'll have to see if it will fit without too much hacking and grinding.

I suspect that one of the reasons my B3 is a bit more accurate than my tf97 is just because the oem  B3 spring has less punch, less than 500fps based on my pellet drop calculator.

Acuuracy/power, hard to get both but fun to try.

regards
don

[scanb3]

My B3 when new.

[scanb3]

New try:

I tought to tell mods I have made to my .177 B3-1.

I think that first thing was to hone sylinder. I used sand paper wrapped around some cloth that was wrapped around drill bit. Nowadays I use brake sylinder hone for that job. I also made transferport little larger with 4,5 mm drill bit. Barrel needed some bending to get scope adjusted. There was also some burr in chamber end of barrel, which made pellet setting more difficult than I wanted.

Then I got idea to chop the barrel. Original pipe was 45 cm long and I took off 20 cm. Velocities was within a few meter/second before and after. Because of dieseling, it is hard to say exact numbers. Anyway, Beeman Kodiak extra heavy shoots about 150 m/s.

Here is pictures when B3 was new and after cutting.









Top quality muzzle:



After some shooting I noticed interesting feature. First shot of the day was about 10 cm apart from the others (distance 25 meters). I figured out it was due barreltime variations, because velocity difference didn´t explain that. It was time to replace leather seal with synthetic one.



I used seal from qf-2 sercive kit and added washer or two to both end of the spring.












As a result velocity is now constant from the first shot and  went up significantly. Here is picture, shot with 7 grain Geco. Both string first of the day.

[70GTvert]

If you get into any modifications, DO not make the same mistake I made with one of mine. I wanted more volume, so I ground the top of the piston about 1/8 of an inch, liked the increase in FPS so I then ground it 1/4 more. This weakened the top of the piston to the point that after one of the cocking cycles, it auto-fired by blowing out the piston top. Now, IF that happened while I was still loading I would have lost the ends of at least 2 fingers, no amount of safely holding the cocking lever through the whole loading process would have prevented it. Luckily, it did it after the loading cycle and while pointed at the ground. DO NOT GRIND the end of piston even a little. This was a bad tip I saw somewhere that I carried to an extreme.

That being said, his mod above works (different versions of it are out there, some with coins instead of washers, why, who knows, those washers are cheaper!) That being said, a good power-plant "blueprinting" ie: Tune, with one of those replacement QF2 springs makes these into sweet cheap shooters. Here are two of mine, both Industry and South Summit versions, that are "Safe" to shoot!

[rr_shooter]

Scanb3 -

What washer sizes did you use to make the mount for the synthetic seal?

[irocz28]

Thanks for the pictures of the switch from leather to synthetic piston seal.  I see the same behavior with my B3 leather seal.  I have two, .177, .22.  The 22 is from south summit, has the synthetic seal.  Shoots very good.  The 177 is a toolsnow with the leather seal.  Even with soaking in neatsfoot oil, roughing up and expansion washer mod, not as consistent as the 22 with synthetic seal.  Easy to switch back too.   Need to get a chrony someday.

[scanb3]

I have some of them in my garage behind ice, snow and darkness and I am in pyjamas. I will check dimensions some day, but I believe they are M5 and M6 fender washers.