Novice Tune-Up on a B3-1

[hyounker]

Thanks again to all who have helped me get this far with this old airgun.  I really thought I had a piece of junk lying around!  We’ll see, in time.  I’ve decided to chronicle my tune-up here so that others can critique my work and my results.

Yesterday, I shot the airgun for the first time in about 15 years!  I started by cleaning the barrel.  I pushed a dry patch through the barrel with a brass jag just to see what came out.  The patch was covered with rust, so I pushed a couple more through with some Hoppes Solvent on them.  It took awhile, but I finally got a patch to run through clean.  I then pushed a patch through with some Remington Oil on it, then several more dry patches followed that.

I shot about 40 rounds of Crosman Premier Hollow Point Hunting Pellets trying to get a feel for the trigger.  I hope the trigger can be improved.  It is flat out, AWFUL!  In its travel, there are three distinct “releases”, the last one firing the piston.  Nonetheless, I felt like I could predict its travel well enough to shoot in a consistent manner.

I measured off 50 feet from my shooting bench and hung some targets on a cardboard box.  I purchased three different types of pellets locally to try with this airgun.  I chronographed 5 rounds of each type with a Chrony Gamma Master and then shot five round groups into targets from 50 feet.  The tins did not indicate a pellet weight, so I weighed 20 of each on my digital reloading scale and divided the total by 20 for an average weight.  All shots were fired using the factory iron sights.  Of course, POI was nowhere near my aiming point with any of the pellets.  I don’t think it’s a surprise that the pellet that demonstrated the lowest standard deviation over 5 shots was also the most accurate pellet.
Here’s all the results:

Crosman Premier Hollow Point Hunting Pellet
Average Pellet Weight:   7.9 grains
Chronograph:      552
      524
      515
      538
      507
Average fps                        527
SD      16
See picture below of Target #1
Group Size:   1.375”

Daisy Precision Max Premium Grade Pointed Lead Pellet
Average Pellet Weight:   7.2 grains
Chronograph:      563
      534
      571
      544
      548
Average fps                        552
SD      13
See picture below of Target #2
Group Size:  2.875”

Crosman Premier Pointed Hunting Pellet
Average Pellet Weight:   7.4 grains
Chronograph:      557
      548
      559
      553
      548
Average fps                        553
SD      4.5
See picture below of Target #3
Group Size:   .8125”

Anything stand out to you guys, good or bad?  Did I do anything stupid?  Is there anything else I should do prior to tearing this thing down?  Thanks again for all the help.

hyounker

[70GTvert]

Well, that hops was not the best idea. Any solvent like that can lead to detonation (use goo gone instead), but based on your #'s, I doubt it is or it would be higher.
There is a rebuild kit you can get from South Summit for about $8, comes with a better spring, trigger sear, piston and breach seal, and fire starter (cheap used oil). That spring will be able to get you up into the 700's if everything else is good. Best $8 you'll spend. If your seal is leather, soak it in some oil (I used 10w30) for a few days and squeeze all the extra you can out when you install. This will lead to detonation for the first 25-50 shots, but after it will calm down and keep the seal nice for a long time. I like the leather better because it fits any deformities better.

[naildigger]

I'm interested in how much improvement you get after tuning on that gun. so, keep us posted.

[hyounker]

I had read about the possibility of detonation with that kind of stuff in the barrel.  I literally ran 20 dry patches through that barrel to finish.  I was actually more worried about the RemOil that I used to wipe away the Hoppes.

Don't forget, your dealing with an old primer and powder guy here!!!  I really had no idea how to clean that barrel the right way.  I did some searching, but I couldn't find any real specifics, so I went with what I know!  Mistake number one!

Will the kit you mentioned have a replacement for the seal in the picture below?  Not sure what it's called, but noticed while cleaning the barrel that it was cracked, then noticed during shooting that pieces had fallen off it.

Again, thanks for the help.

Henry

[hyounker]

Thanks, naildigger!  I'm as anxious as anyone!

Henry

[70GTvert]

Breach seal, and yes it is included.

[hyounker]

I'm ordering some things to get started on this airgun and have decided to go ahead and order a scope and mount.  I am also waiting for a brand new Gamo Whisper to come in the brown truck.  What do you call the scope mount dovetail on the B3?  And will the Whisper have the same dovetail?

Thanks,

Henry

[scanb3]

If you deside to use one piece mount, pay attention to very short rail on b3.

[hyounker]

scanb3,

Will this work?:

http://www.opticsplanet.net/leapers-airgun-22-1-bi-directional-offset-optimum-profile-mount-rgpmofs38-25h4.html

The base length is only 62mm, as opposed to 100mm for most other Leapers.  I measured the B3 and it looks like you have about 3.25" of useable dovetail.

Also, is this dovetail 11mm?  And will the Whisper be the same?

Henry

[davee1]

Henry, I'm not ScanB3, but I'm sure you are looking forward to answers...so if I may, I'd like to jump in.

Yes, I think that offset mount will work on your B3. On mine, the dovetails are approx. 3.25~3.5 inches of usable groove(80~90mm), and you were sayin that yours is about 3.25". If that offset base is only 60mm, then you should be ok. I always ask how you can stop the base from moving though...so there needs to be some kind of stop.

There is always questions about the size of airgun dovetails, and I will venture to say that after measuring my B3, its about 11mm. I cant be precise, because we need a standard for actually measuring the dovetails. One standard is to put a 1mm rod in each grove and then measure the OD between them, but I have no 1mm rod so I just measured the top width.

I'd like to mention to you that you can make your own breech seals out of soft tubing, fuel hose, vinyl hose...I use 5/16" fuel hose. I like the way that seals better than the stock breech seals. My 5/16" fuel hose is about 17/32" OD, 5/16"ID, and about .350" long...got it at ACE Hardware, but lots of places have it. Take out those old peices of seal, push in a new length of hose, close 'er up, and you are there. Might have to experiment with the length though...the trick is to get that baby so that when she closes up there's a slight resistance, which is the loading port cone pushing into the hose/seal, and sealing up in the process. Too long and she wont close properly, too short and she wont seal all the way. With a good breech seal goin on, your velocity/consistency will come up quite a bit...it might be surprising.

[davee1]

The Whisper has grooves cut into the rcvr just like the B3 and they are about the same size in width. The whisper's grooves are quite a bit longer though, and it has a clamp-on rail that fits into the grooves and acts like a riser somewhat, and also has scopestop pin holes. Here's a pic of the front of the Whisper rail:

[shadow]

With a hopefully decent B out of the box and some good TLC you should be able to squeeze 600 to 700+ out of one. Ed

[hyounker]

Jumped into the B3 today after finishing up my very rough version of a spring compressor.  Worked like a champ though!

Everything went as expected.  The surprising thing about the disassembly was that nothing was much of a surprise.  All the information that I gathered on this site had me very much prepared for the task.  Thanks to all.

I did find one thing inside the ole B3 that looked different from what I expected.  During all my reading and research here, I don't remember seeing a spring guide like the one that popped out of my B3.  Pictures below.  Comments appreciated.

I cleaned all the parts today with mineral spirits and soapy water, then blew them dry with compressed air.  I'll start polishing tomorrow and through the weekend as I have time.  Still waiting on the kit from South Summit.

[hyounker]

Hey Guys,

I haven't heard anything about that spring guide in my last post.  Was hoping to hear if others have seen it before.

Started deburring today and found a problem.  Should I fix this broken weld, or is it okay as is?  The weld that attaches the rolled steel together on the piston has broken (opposite end from seal end).  Seems like conventional wisdom would say to fix it, but I think I've learned to ask you guys before I jump into something like that.

Thanks for any help.

[davee1]

I don't know if you should weld that...but I have seen the metal spring guide in the XS-B3-1, which looks like a AK47. A well built airgun IMHO.

I have 2 B3s and they both have the plastic spring guide. Metal is not a bad thing...will last much longer in the long run...and Moly clings to it real good!!!