Snow Peak Airgun Model WF-600 Rifle
A few members on the forum have posted about the SPA WF-600 underlever spring rifle. Curiosity finally got the best of me so I ordered a .177cal version to test out. I already knew this rifle would be a project rather than an instant shooter. As forum member Ricksplace said it, the WF-600 is a "preassembled unfinished air rifle kit". Out-of-the-box my rifle was cosmetically fine on the outside but internally rough and in need of attention.
The Project Begins As soon as the WF-600 arrived I unboxed it, cleaned the barrel and cleaned the barrel again and again. Mild surface rust in the barrel! The first few patches came out orange so the barrel was flooded with a few blasts of Slick 50 One Lube and set aside to soak. After continued treatments with One Lube, WD40 and some specialized gun cleaning products, the orange colour continued to show on patches although to a somewhat lesser degree. I also noticed that when pulling a tight fitting patch, the last 1/8” at the muzzle required a good yank to get the patch to exit. There was some sort of lip formed on the inside of the crown. I’m guessing a dull crown cutter in conjunction with excessive cutting pressure formed the inward rolled edge.
Even with the mild surface rust and a messed up crown I still shot some groups for a baseline. Accuracy was poor, as expected, with ¾”+ groups at 10m. Velocity clocked at a respectable 495-515 fps with 7.9gr pellets (non-PAL rated). I recrowned the rifle using the common procedure with domed brass screws and various polishing/grinding compounds. The crown turned out fine and accuracy improved a bit but not as much as desired.
Next, I disassembled the rifle and slowly pushed pellets through the barrel with a cleaning rod (breach to muzzle). A definite constriction could be felt about ½” from the breach end. Pushed pellets were very tight at first and then loose/moderate for the rest of the barrel length. During assembly the manufacturer must hammer these barrels into the receiver tube for a tight pressure fit. I spent quite a bit of time carefully sanding the bore with 400 and 600 grit sandpaper to remove some material from the breach end. I followed up with a mixture of JB paste and jeweler’s rouge followed by a good bore cleaning. Pushed pellets now felt snug through the entire barrel. The barrel is now shiny like a mirror inside with no orange rust stains shown on cleaning patches. Patches come out with a touch of light grey rather than undesirable orange. I finished up the barrel by sanding the exterior of the breach cone to remove machining ridges that would eventually eat the soft breach seal. The sharp pellet entrance on the bore was beveled a tiny bit and the perimeter of the receiver’s loading port also got some attention to remove the sharp edges.
The compression tube and piston seal look great. The trigger engagement parts look amazing! The piston looks like a rough cast iron pipe but the stretched hourglass shape ensures no surface contact except at the ends. I polished the end areas a bit and also the inside of the piston.
The OEM spring guide is a molded plastic arrangement that looked functional but had much room for improvement. I installed a custom steel guide, top hat and thrust washers made by Ricksplace. The OEM spring was 27 ½ coils of .118” wire. The substitute was a new Crosman 4B spring with 33 coils of .118” wire. As always, the spring ends were polished to remove the grinding marks. Preload went from only ¼” with the OEM spring to a still manageable increase that I didn’t measure.
While I was shooting the WF I had to max out the scope elevation in order to hit center at 10 metres. When I disassembled the rifle I looked down the receiver tube and noticed that the barrel was drooped. After completing the bore sanding treatment, I stacked three short pieces of 2x4 on the basement floor and smacked the barrel firmly about 15 times. I held the receiver tube and hit the wood right behind the front sight. This gave a mild bend that was not even visible with my old eyes. Shooting tests showed that the POI came up and gave back at least a full turn of scope elevation at 10 metres.
Moly paste was used on all friction areas including the trigger parts. Tight fitting areas such as peened pins got a mixture of moly paste and 30W oil that was coaxed into the crevices.
The wood stock on this rifle received the SuperGlue treatment to all the inletting. SuperGlue is a cheap way to strengthen up the wood fibres on these soft stocks. A thin coat of Spar Urethane on top of the glue completed the inletting treatment. The buttpad seemed to be glued on, as well as screwed, so I couldn’t seal underneath. The exterior surface of the stock looked fine so I left it alone for now.
The trigger on these rifles is non-adjustable but doesn’t feel too bad after a moly paste treatment. It’s a bit squishy while taking up the spring tension but the final movement is short and not overly heavy.
After the above procedures and about a hundred shots the velocity was checked again. It was pretty much at 600fps (8gr pellet) with a 5-shot string recorded as: 592, 588, 592, 597, 596 fps. SPA rates the full powered .177cal version at 560fps but they don’t state a pellet weight. The rifle does okay for velocity considering the short 2 1/8” power stroke.
Fit and Finish The fit & finish on this rifle is far from a Weihrauch or Diana but so is the price. The metal barrel and receiver tube did not show any gouges or heavy machining marks. The metalwork was not heavily polished but looks no worse than some of the current Savage rimfire rifles I have seen. The bluing is fine with no unsightly blemishes or colour irregularities. The metal appearance actually looks much better than I expected.
The plastic parts include the front sight, rear sight, trigger guard and receiver end cap. These parts appear fine and without defects or colour flaws. The black plastic seems to be hard enough and durable.
The wood stock is more than just a functional handle. The contours work well and the 13.5” pull length wasn’t something that I needed to mess with. The comb was the right height for using the iron sights or optics. I mounted a 3-9x32AO UTG scope and the comb height worked great with the medium mounts. The finish on the stock is some sort of medium brown stain with a clear coating. The wood grain can somewhat be seen through the thick finish but so can many little flaws that were repaired prior to the finish aplication. It looks a lot better than some Norinco rimfire rifle stocks that I have seen.
The stock-to-receiver tube fit is quite good on my example but the trigger guard has some gap on the sides. It’s not a huge gap and doesn’t look unsightly. The rubber buttpad fits tight without the common overhang we see on cheap airguns. The rifle appearance definitely exceeds the $100 price tag.
Accuracy Tune complete. Let’s check accuracy!
Targets are attached for 10m, 20 yards indoors and 30 yards outdoors. I’m a bit confused about the 20 vs 30 yard results. The difference is a bit less than I think it should be for the JSB pellets. I physically measured all distances so I’ll just post the numbers. I’ll test again if I can get a good day for outdoor shooting. The JSB Exact Express pellet was tested twice at 20 yards. All groups were 5 shots.
10 metres JSB Exact (8.44gr) – .33, .36, .35 ------------ Ave = .35” ctc JSB Exact Express (7.8gr) – .28, .26, .16 --- Ave = .23” ctc JSB Exact RS (7.33gr) – .19, .29, .24 ------- Ave .24” ctc H&N Sport (8.0gr) - .38, .41, .40 ------------ Ave = .40” ctc
20 yards JSB Exact Express (7.87gr) - .58, .50, .38, .56, .33, .35 --- Ave = .45” ctc JSB Exact Express (7.87gr) - .56, .38, .52, .47, .36 -------- Ave .46” ctc JSB Exact RS (7.33gr) - .52, .58, .72, .40, .56, .36 -------- Ave = .52” ctc H&N Sport (8.0gr) - .46, .66, .65, .68, .48 ----------------- Ave = .59” ctc
30 yards Air Arms (8.44gr) - .85, .87, .82, .88, .79 -------------- Ave = .84” ctc JSB Exact Express (7.87gr) - .53, .49, .56, .78, .80 --- Ave = .63” ctc JSB Exact RS (7.33gr) - .70, .57, .36, .75, .54 --------- Ave = .58” ctc H&N Sport (8.0gr) – 1.16, 1.14, 1.15, 1.27 ------------ Ave = 1.18” ctc
Notes and Final Thoughts: • I also tested accuracy with H&N Field Target Trophy, H&N Finale Match Rifle, RWS Meisterkuglen Rifle, RWS Hobby, JSB Match, CPHP, and Crosman SuperMatch. None of these pellets shot as well as those above. • The rifle seems to be getting more accurate the more I shoot it. I’ll likely retest accuracy after another 500 pellets. • As a general rule, unchoked barrels can be quite pellet finicky. The WF is another example that follows the rule. • I’m not sure if I had a fluky day when doing the 30 yard groups. I would guess the groups should have averaged around .70” or .72” at 30 yards. The .36” group at 30 with the RS was a definite fluke. • The H&N Sport groups seemed about right for 10m and 30 yards but the 20 yards numbers seemed too low. No explanation. • I’m still trying to figure out the accuracy and how to best shoot this rifle. I have to figure out what causes the occasional flyers or larger groups. Maybe I need to experiment with the benchrest set-up. • I didn’t use Loctite at all because I thought the mild power wouldn’t be a problem. Unfortunately, I had to tighten up the scope screws and stock screws a couple of times so I’ll be doing the Loctite soon. I’m sure this issue didn’t help accuracy. • Loading this rifle is not easy like a break-barrel rifle. It requires a different technique and using a scope that stretches over the loading port creates more of a challenge
Attachments: |
WF600 with UTG 013b.jpg [ 382.2 KiB | Viewed 3221 times ]
|
WF600 parts 006b.jpg [ 333.41 KiB | Viewed 3221 times ]
|
WF600 parts 019b.jpg [ 304.95 KiB | Viewed 3221 times ]
|
|