Derrick Lightens His Webley Tempest Trigger

A few weeks ago, I bought a .177 cal Webley Tempest pistol from world-renowned airgunner, Wayne Burns. Thanks Wayne! When I shot the gun, I thought the trigger pull was in the 12+ pound range. (Not Wayne's fault!) It was like a Glock with the "New York" trigger. When I told Nick how high it was, he said I must have the target model! Both Webley Tempest and the similar Hurricane air pistols (same base guns, different sights) share the same trigger mechanism. Until recently, I'd owned a Hurricane for about two decades and that trigger was just as heavy.

Nick and I pondered the trigger situation. Then, Nick forwarded this link: http://www.rimfirecentral.com/forums/showthread.php?t=219638
Seems like I'm not the only one who thinks the trigger pull weight is absurdly high.

The trigger is retained with, yep, small roll pins. What a great way to start! More required reading: Nick disassembled a Webley Hurricane on a previous blog post. Pay attention to the way he numbered the roll pins for disassembly. Handy! http://anotherairgunblog.blogspot.com/2008/05/disassembling-webley-hurricane.html
Note: Worry not. There is exactly zero danger that the mainspring will come blasting out of the gun by removing the roll pins.

Grip panels off. Unscrew the flathead holding the safety lever and pull it off the stud. The safety spring then comes right off.

Knock out the roll pins in the order Nick has them marked in blog post #31. Not necessary in the least to push them completely out of the frame. I pushed them out from left side to right.

The trigger and sear are buffed (bench grinder fitted with a 6" stitched wheel). Lots of polishing compound on the wheel. A small container of water near the buffing wheel keeps the part cool. All the mating faces are polished until they look like mirrors.

Trigger and sear after buffing. The allen set screw behind the trigger blade gives the spring something to bear against. Screwing it in increases trigger pull weight. Backing it out lowers. The trigger spring is so stiff (and so long) that the set screw only really gives you the option of "too high" and "really too high" in it's adjustment range. The spring is 0.145" diameter and 0.616" long--"free length" in spring speak.

The trigger shoe is from Crosman It's for their 2300 custom shop guns. It fits quite well. Crosman part number 2300-012. About $9 if I recall. It's not always available for after market sale. Beeman used to sell a really nice steel trigger shoe from Flaig Ace. Beeman's old part number was #7761.

I looked around at all my springs, but couldn't find anything small enough in diameter to replace the stock trigger spring. A trip to several local hardware stores also came up dry. It's possible that Webley used a metric sized spring. If that's the case, it's probably a 3.75mm OD and it crushed very, very slightly when I put a caliper on it. I found several good options in a few seconds online, but didn't want to order and wait. I chose instead to cut 2 coils off the spring to lower the preload. Alternately, it might have also been possible to change to a shorter set screw in the trigger itself that bears against the spring. Either way, the spring will then exert less force against the sear.

Pick your poison. Just cut the spring shorter. Reassemble in the reverse order. I lubricated all the contact surfaces with Castrol MP grease. Use whatever bearing/chassis grease you have around. And, yes, a moly grease is fine for this as well.

The return spring for the sear goes in this way. This is the only part that might cause some head scratching during reassembly.

There's a relief cut on the trigger guard for the long leg of the return spring.

Gun is lying right side up. Long leg of spring is on top and towards the front of the gun.

The short leg at the rear of the return spring fits in notch cut in the sear. Notch is there at the top.

Once the guard is pinned back into place, only the safety lever needs to be reinstalled.

Have I mentioned yet that these Webleys have single-stage triggers? Well, there you go. The trigger pull weight can be fine-tuned using the set screw at the rear of the blade with a 1/16" allen wrench. By adjusting the set screw to preload the trigger spring, my pull weight was variable from a high of about 4 lbs 2 oz down to 2 lbs 8 oz. Mine is currently adjusted to about 2 lbs 12 oz. Pretty good considering it was in the 8 pound range before the job. It's still not "match grade", but perfectly acceptable for a fun plinker.

Side note: IF the set screw is backed out of the trigger blade more than approximately 0.120" from flush, the gun will fail to cock. The protruding set screw will contact a shelf inside the rear of the trigger guard and the sear will not hold the piston back. Turning the set screw in a few turns will immediately fix the problem.

Warning to Americans: I failed to match up the thread size on the set screw. It's not metric--and it doesn't match up with SAE. It's probably a BA #4. You are hosed if you drop this under a work bench outside of the UK.

Slipping Scope Mounts on a Webley Patriot

Spring piston air rifles are notorious for their ability to move scope mounts rearward on their dovetail from recoil. The dovetail is typically 11mm wide and offers little surface area for ring clamping  To address the problem, many if not most such rifles come with a stop hole (or three) drilled into the top of the compression tube at the rear of the dovetail.  And most of today's scope mounts have a requisite recoil arrestor pin to fit into the hole.

But what if your rifle doesn't have a stop hole?  Or maybe it's not in a convenient location for your chosen scope mount?   Maybe your scope rings won't accommodate a stop pin?

Maybe this will help.


Backstory:  The cycling industry had a problem a few years ago when carbon fiber became common place.  The smooth surfaces and relative fragility of lightweight carbon parts presented a clamping and fixturing challenge. Carbon seatposts, stems and handlebars would often slip under rider weight.  Parts wouldn't stay in place.  Torquing the fasteners beyond spec was an all too common (and bad) solution as it deformed and crushed the carbon fiber ruining the expensive components.   The cycling industry's earliest and simplest fix was to have mechanics add a friction paste to the clamping surfaces of parts.  The paste contains fine silica that provides bite or "tooth" to the mating surfaces and substantially increases grip for the same amount of fastener clamping torque.  The cycling industry calls it "carbon assembly paste".  It's  available at any halfway decent bicycle shop or through the internets.

Finish Line Fiber Grip, Tacx Carbon Assembly Compound, Park SAC-2, FSA,  Whatever.  It's all silica in an inert carrier. 

OK, so there's all that.  What's that got to do with me?  I've got this hard kicking Hatsan Manufactured Webley Patriot.  It's a known scope mover and breaker.  I've heard of several now that have even broken the stock mounting bolt--including this one.  There's no conventional stop hole on this rifle.  Webley uses shallow cross grooves as the scope stop and that requires a special mount. 

I really don't want to try to find one--especially for a 30mm scope tube.  Just wanna use this cheap Walther red dot and mounts I already own.  Without a proper scope stop, figured I need to get as much grip on the dovetail as possible.  To increase my chance of success, I used an 11mm to picatinny adapter that has about 4" of clamping surface and four clamping screws.  The picatinny cross slots ensure the rings won't move.

Before installing the 11mm to picatinny adapter, I degreased, then gooped up the rifle's dovetail with Finish Line carbon assembly paste.  Tightened the bolts, then installed the rings and red dot. 

 

 

Gritty!

It's been a week and a hundred shots and it hasn't moved at all.   Obviously not a definitive test, but it's a good start.  This would probably also be the ticket on scoped IZH-61 rifles that have that plastic receiver and dovetail with no stop pin hole.  It promises extra grip without crushing that plastic rail.

Will this work?  It's definitely going in the right direction.  Without a mechanical stop, increasing the friction between the dovetails of the rifle and scope mount is the only other option to end recoil induced movement. 

I'm not exactly sure what constitutes success.  Guess it's going to be subjective.   For me, it'll be a success if the red dot stays zeroed for five hundred shots with no apparent shift.

Disassembling a Webley Hurricane

I took apart the Hurricane Derrick sent me. I followed the disassembly and reassembly instructions in the manual. I wish every airgun came with as good instructions. I couldn't find a copy online, and there isn't one up on Webley's website, but they may be able to help if you contact them. They do say they "plan" to have historic manuals up at some point...

The Hurricane.

The other side...

These five roll pins are removed with parts in this order.

A spare pin pinch was "precision ground" down by spinning in a drill against the belt grinder. The diameter should be .089" (2.25mm) diameter.

Pins 1 and 2 removed, the trigger guard and sear spring.

Pin #3, and the trigger comes out.

Pins 4 , then 5 and the sear comes out.

The safety is removed.

Then another pin to remove the front shroud.

The pivot pin is tapped out just enough to remove the barrel linkage, but still retain the spring guide.

Then fully removed to allow the spring and guide to come out. It will shoot forward a bit so it's best to have it pushing against something so to control the release of the spring.

The piston was persuaded out. I had a little lube on it.

Then the barrel latch pin was pushed out.

The sight was removed by unscrewing the elevation screw, then removing the two screws that attach it to the pistol.

The rubber breech seal was pried out with a small screwdriver. It had been mounted backwards, not that it probably makes much of a difference.

The spring guide seemed a bit rough.

So I spun it in the lathe and lightly sanded it to polish.

The pivot pin seemed worn so I found a dowel pin of the same diameter and turned it to length (carbide tooling...)

The gun assembles almost in reverse of the dismantling. Pretty easy. I just lightly lubed that which needed lubing and took out a few burrs on the cocking slot.
The gun chronied almost exactly the same as before disassembly, but seemed a bit smoother...
a bit...it is a Hurricane after all.

Derrick's Beeman P17 Overhaul Finale

Back to the overhaul. Time to remove the compression chamber and the valve assembly. Using a 2mm allen wrench, loosen the setscrew bearing against the cross pin anchoring the chamber to the lower grip frame shown below.

It's unnecessary to remove the setscrew. About one full turn out is sufficient.

With the setscrew loose, drive the cross pin completely out with a drift.

The compression chamber lifts right out. At the bottom of the chamber there are 3 steel "fingers" held in slots by a small cross pin. Punch out the small pin and pull the "fingers" out of their slots. Note that the center "finger" is different at the base. The small tab at the bottom guides the sear through its travel pulling the hammer. It's not a bad idea to polish the bottom guiding edge of that center finger.

Here's the compression tube. The breech o-ring can be seen near the top, left side. The valve stem is sticking out on the top right. It's a pull open valve. The hammer pulls the stem downward releasing the trapped air through the transfer port at the breech.

A 13mm wrench removes the brass nut to access the valve.

Oops. Pulled the top o-ring off already. I'm ahead of myself. The o-ring fits on the end of the valve stem in the groove. It's a #006.

I took that #006 o-ring off so I could carefully hold that end of the valve in a padded vise. A 7mm wrench removes the black nut that the hammer pulls against. The stem is peened slightly so the nut won't come off in use. Removing the nut also removes the slight peen and allows for complete disassembly.

I polished the entire valve stem on the buffer and carefully cleaned off the buffing compound. I also found a higher quality replacement hnbr o-ring (the green colored o-ring) to seal the valve circumference. Note: this o-ring is the same size as the breech o-ring.

Buzzy's Slick Honey is a superb o-ring lube--especially for sliding fit parts that still need to air seal.

The threadlocker will replace the peening I removed.

Thought I'd also teflon tape the valve nut. You know...just in case.

The PTFE tape was too wide. I cut it in half lengthwise and gave it three full wraps.

Got all liberal with the Slick Honey. Seriously, this stuff is almost impossible to wipe off. It is incredibly thin and lasts dang near forever. It was first marketed years ago by a world renown suspension tuner, Arlo Englund, as a shock bushing grease. It was first called Englund Slick Honey. Be sure to at least lube the o-rings.

Here's the reassembled valve. I didn't have a hnbr o-ring small enough for the valve seat seal. WHAT? I know. It seems impossible to me, too.

She goes back in like this.

Holding the stem stationary while threading the brass nut back in will prevent damaging that #006 o-ring.

A dental pick lifts out the breech o-ring. If better sealing against the breech was required, this is where a small super thin shim would be placed, then the o-ring reseated.

Ah yes. My green 0-friend.

Did I mention that the black nut was installed with a thread locking agent? I don't want the nut to loosen at all in use, as the hammer pulls the black nut straight down to fire the gun.

Time to reassemble. Almost as an afterthought, I decided to quickly polish the main pivot pin for the upper assembly.

Polished out. This was the pin with the small e-clips from part one.
Please refer back to the earlier post's pictures for reassembly. Essentially it goes back together as follows: First, reinstall the barrel into the top cover. The compression tube was then pinned back in place in the lower grip frame. Don't install the piston yet.

Let's put this mess back together first.

This is actually very straightforward. About 11 individual parts, but only 3 assemblies. The hammer, sear and trigger group.

Here's the hammer assembly. I lightly greased all the parts with the Buzzy's Slick Honey, then assembled the parts onto the pivot pin.

Like this.

Then, put the hammer assembly onto the valve stem and rotate it forward on the stem and into place, pressing the pin into the hole. Notice, I did not attach the small coil spring onto the lever just yet. Then, I reinstalled the torsion spring into the bottom of the hammer assembly and set the center of the spring loop onto the post molded into the grip.

Don't seat the lower end of the torsion spring. Leave the tail end of the spring hanging out the rear of the grip as shown above. Now the sear assembly can be slid into location.

Here's the sear with it's small torsion spring oriented correctly. Not shown is the pivot pin. As an aside, I should mention that in my gun--and in buddy Jason's--the hammer and sear were about as hard as glass.

I've had best luck installing the pin just far enough to go through both the spring and the sear and then sliding the sear forward through the hammer assembly. Push the sear's pivot pin into it's hole. Don't tension the sear's torsion spring.
Now is a fine time to install the trigger and trigger axis pin. No pics necessary.

Using a small pair of needle-nosed pliers, reattach the small coil spring to the hole in the lever (part of the hammer assembly) and hook the bottom loop of the spring onto the post directly below. The coil spring is directly behind the trigger if you look at the above picture.

Here's another view of that coil spring. Finally, using the needle-nose pliers, tension both the sear and the hammer torsion springs by seating their ends into the grip frame. They bear directly on the inside plastic of the grip housing. Replace the right side grip panel--taking care to align all the pivot pins, and snug down the single grip bolt with a 2.5mm allen wrench.

Pin the top cover assembly (barrel housing) back together with the long cross pin, snapping the e-clip into place. Finally, it's time to install the piston. Is the piston's #116 o-ring in perfect condition? If not, replace it and lightly lube the o-ring so it forms a positive air seal. MOST of the P17 problems will be traced back to this single o-ring. Slide the piston into the compression tube, tap the pin back in and snug down the 2mm set screw.

With this setscrew, it's done.

Shooting the gun across the chrony with a wide variety of pellets gave the following numbers:

CROSMAN PREMIER WADCUTTER ---VERY CONSISTENT
376.9, 376.1, 377.3, 379.8, 380.8, 380.6, 379.5, 379.2, 380.5, 381.5

GAMO MATCH WADCUTTERS
374.5, 383.1, 378.2, 384.5, 381.0, 385.1, 381.8, 387.5, 386.1, 387.0

BEEMAN SILVER BEAR HOLLOWPOINT ---FAST!
399.6, 399.4, 401.1, 405.3, 402.5, 403.9, 406.8, 401.3, 406.2, 411.6

And just for fun some weird ones,
WEBLEY FLYING SCOT
388.2, 369.0, 388.6, 382.8, 376.5, 380.8, 393.1, 374.5, 378.7, 384.8

BSA PYLARM
366.5, 373.8, 380.3, 385.1, 381.2, 379.6, 369.6, 392.1, 383.7, 371.7

A strange fact: While Beeman has sold this gun now for several years under 3 different model names, it's never been listed on their website.

Updated note:
I've gotten many questions about P17's dumping their air on the closing stroke. Mine started doing this the other day and I immediately assumed it was the air valve not seating. A rebuild of the air valve showed nothing was wrong and the problem continued. Close examination revealed that the sear wasn't catching the hammer consistently. Sometimes it worked fine, then--whoosh. Frustrating. It appears that the problem was the v-shaped hammer spring binding inside the grip frame. I'd put the rear end of the spring into the left grip panel on reassembly and that's not the way to do it. The tail end of the spring must be seated into the RIGHT grip panel or the spring will bind.