SPA WF600 (B3-4) clean-up, re-lube and tuning

[airmec]

In this thread I’ll be detailing the clean-up and tuning work I did on my Snow Peak Airguns model WF600 (wood stock) underlever in .177 caliber, non-PAL. The gun was bought brand new (thanks AGS!) and shot only once before tearing it apart. I have some experience with Chinese airguns, and when I shot this one I felt it would benefit from a good overhaul.

I’ll start with the trigger and anti-beartrap mechanism, which were in good need of attentive cares. The B3-4 trigger has nothing in common with my BAM/Xisico B4-2 trigger (cheers Ace!), it seems to be a copy of the BSA Super Meteor trigger :

https://www.pyramydair.com/blog/2018/04 ... er-part-5/

https://www.pyramydair.com/blog/2013/10 ... or-part-2/

The trigger parts are well made, the sear and trigger are MIM with a nice finish, the trigger blade itslef is stamped sheetmetal. I needed to slightly re-work the trigger blade parts as there was almost no ‘’first stage’’ before let-off.

The anti-beartrap bar was a little bent upward, and needed some de-burring/polishing, but works well other than that. It positively locks the trigger as soon as the underlever is about 2 inches out of the ‘’rest’’position.

The safety is well thought and effective, there’s almost no fore-aft play in the trigger blade when ‘’on safe’’. It’ll benefit from some smoothening/lightening though.

More to come, to start here’s some pictures of the anti-beartrap and trigger, last one shows all trigger parts :

[airmec]

Here in the T_4 picture you see the tiny ’’first stage’’ spring in between the trigger blade and trigger lever. The T_5 picture shows the trigger blade assembly parts. I took it apart to be able to have some first stage travel, and to lighten the spring pressure a bit too, as it was almost as strong as the ‘’second stage’’ or let-off and gave a very imprecise feel of the trigger.

[airmec]

Next, in the T_6 picture you see the original height of the first stage spring, in the T_7 picture you see it sitting about 1/16’’ lower after I bent it. This cuts the first stage weight about in half.

[airmec]

In the T_8 picture, the edges and contact surfaces of the trigger lever (the main piece in solid steel) and sear were very lightly polished with 400 grit sandpaper (sorry for the blurry pic). They actually didn’t need much work, they had a pretty smooth finish already from factory. The area where I put most efforts is where the end of the trigger/sear ’’L’’-shaped spring seats in the trigger lever (circled in red). I rounded and polished the edges as they were very sharp, I didn’t want to risk a trigger spring failure because of wear.

In the T_9 picture the top of the sheetmetal trigger blade was de-burred and polished flat, with a wee bit of material removed to get some first stage travel. The pivot being in the middle of the blade, the front and rear edges act as ’’start and stop’’ points for the fake first stage. Please note that there’s no actual sear travel during this first stage.

T_10 shows you the trigger parts ready to be lubed and re-assembled. I have left the ’’L’’ trigger/sear spring alone, I didn’t try to make it softer by re-bending. It wasn’t that heavy to start with, much less than on my B4-2, and with some tungsten paste on the parts I’m sure it’ll do well.

[airmec]

T_11 shows the safety lever. The edge the spring goes over was gently rounded and polished. This helps having a smoother ’’ON/OFF’’ action, I do this on my Crosman B18/19 safeties too.

In the T_12 and T_13 pictures you see the anti-beartrap bar or lever. The cocking lever slot is factory de-burred, but the end that goes into the trigger needed some re-shaping and polishing.

[airmec]

In T_14 the small pin (red arrow) under the safety lever was a bit too long and interfered with the lever. I just grounded one end smooth, that was enough to have it clear the lever but with no excessive side-play.

In the T_15 picture you see the small gap at the rear of the trigger (red arrow), this is what allows first stage travel. There was none originally, now there’s a distinct stop before let off. Second stage doesn’t have too much creep, there’s about 1/8’’ of travel before the shot.

Will be back with more.

[JayDee24ca]

What sort of optics are good on these guns? As I understand it, springers tend to eat some scopes due to shock and vibration. So how can I tell what to look for , buying optics for the B3?

[notec]

Ive made this a sticky......great posts like this should remain at the top of the forum.

[ricksplace]

What sort of optics are good on these guns? As I understand it, springers tend to eat some scopes due to shock and vibration. So how can I tell what to look for , buying optics for the B3?

Having owned five of them, I can say none of them blew up a scope, even the "freebie" scopes often included with entry level springers.
Considering the rearward placement of the dovetail and the exposed loading port, a short scope works well to maintain eye relief while not interfering with loading. My current WF600 in .22 wears a "freebie" 4x32 scope in a one piece mount that leaves enough clearance for loading. No problems with it. My other two B3s in .177 wear a compact 3-9x32AO in individual rings. (rings on one piece mounts are spaced too wide)
All three of my B3s are scoped without the need of a scope stop. I use double screw individual rings, or a one-piece base. They don't move.

[TCooper]

I'm still using a cheapo 4X CenterPoint that came with an Optimus rifle pkg. The scope length is 10.5" which brings the scope to the beginning of the loading port. I had a longer 3-9X UTG mounted for a while but loading was a bit awkward.

Some compact style scopes will work with this rifle. Unfortunately the scope grooves do not run to the very back of the receiver tube (like HW does). The shorter groove length prevents the compact scopes from being mounted far back for proper eye relief. Rick found a nice compact scope that has a longer eyepiece and it works great for this rifle.

There is a Discovery VT-Z 4x32AOE scope with mildots that measures 9.06" in length but I haven't seen them advertised in Canada. A red dot would also work on the WF-600 but then you lose the magnification for precision shots.

The Hawke Vantage 2-7X32 AO MIL DOT (14111) might work okay on the WF rifle. It's 11.5" long but the eyepiece looks longish and the objective bell looks short. The Vantage line isn't recommended for springers but the WF has mild recoil.

[airmec]

Ive made this a sticky......great posts like this should remain at the top of the forum.

Cheers Jonathan . Stay tuned, there's more .

[airmec]

In the following part of the rebuild thread I’ll be talking about the work done on the piston/seal, compression chamber and spring/guide assembly.

Let’s start with the spring and guide. In SG_1 you see the still in-place spring guide, please note the rifle is well oiled from the factory! I highly recommend using a safe spring compressor to remove the guide, though with the non-PAL spring there's not a lot of pre-load on the spring, I measured it @ 5/8'' when I got the guide out. A brand new full-power spring would have around 2 1/4''-2 1/2'' of preload (unset).

Next picture (SG_2) shows the factory non-PAL spring (bottom) compared to the full-power spring included in the repair kit (top). The non-pal spring in my rifle has 28 coils, 3 mm wire, a 0.490'' ID and is 7 3/4'' long; the full-power spring in the repair kit has 36 coils, 3 mm wire, a 0.490'' ID and is 10 1/8'' long. I'll be using the non-PAL spring in this rifle.

SG_3 shows the OEM B3 spring guide, made from white plastic (Delrin?) compared to a common Crosman-B18/19 steel spring guide. I wanted to show that, as I saw on the net that the Crosman guide can be swapped in the B3 rifle; this is not the case actually, not easily anyways. Guide rod length and OD are fine, but the spring seat is too high and, most importantly, the cross pin size is not the same at all. To fit, the Crosman guide would require custom work that may not be in the reach of the average hobby airgunner. Just saying.

[airmec]

The way the rifle is made, the spring seats directly on the plastic shoulder on the guide, and directly on the sawn-finish front wall inside the piston. Not good for guide and spring life and noise. I considered using a metal guide similar to the one made by Ricksplace (real nice work BTW Rick!), but I finally opted to modify the OEM plastic one.

I wanted to add a top hat, so I recycled the front portion of the spring guide into one. I started by chopping the guide rod off, then keeping a 1/8'' thick ''shoulder'', I cut it to 1'' total length – see it in SG_4. I made a flat 1/8'' thick hardened steel disc with a mirror-polished face to sit in front of the top hat (this provides a smooth surface for the TH to swivel on), and a 1/8'' thick hardened steel thrust washer for the spring to sit in between the spring and top hat (missing in this picture). The top hat, washer and disc also add weight to the piston, adding momentum, more on that later.

Next I shaved the remnant of the OEM guide rod and drilled a 1/2'' ID hole, 1/2'' deep into the guide base, and machined a new tight-fitting guide rod out of MDS (moly-impregnated nylon, also called Nylatron), about 1/2'' longer than the OEM one and with a 0.002'' press-fit in the base. I assembled the base and rod using 3M spray-on adhesive for a ''forever'' fit. I also added a 1/8'' thick hardened steel thrust washer on the guide rod – see the SG_5 picture.

In the SG_6 picture you see the assembled parts. I use a small coating of Permatex synthetic grease on the guide and top hat parts, and the spring is very thinnly coated with tungsten paste. Because of the added height of the top hat and washers, I made the spring seat lower than OEM to compensate, so that the spring installed height and preload would stay the same as original. However if you look closely at SG_4 and SG_5 you'll notice a difference in spring seat height, as I had to further reduce preload (less than factory) to stay under 500 fps. Spring ''torque'' is now totally absent, as are spring noise and vibrations. I'll come back with more on the performance of the rifle later.

[airmec]

SG_7 shows the new preload of the spring, about 3/8''.

Also see picture SGD_1 for a crude drawing of the old and new spring guide.

[airmec]

Next on the list is the compression chamber. It seems to be made from a piece of tubing and a slug for the front wall, chromed on the outside and with a smooth finish inside. The chrome plating is not perfect as you can see in CC_1 (red circle), but is nonetheless pretty good and should last a good while and work smoothly, especially with some good lube. In CC_2 you see the inside edge of the cocking hole in the rear of the chamber, already de-burred from the factory. Out of the rifle the chamber only needed a light cleaning with some de-greaser.