Construction of the HW80 WK

For the past couple of years, I've been on a quest for a break barrel spring gun that would serve as a field gun as well as a competition gun for both field target and metallic silhouettes.  Every gun I looked at seemed to be a bit of a compromise in one area or another.  Factors such as too little power, harsh shooting characteristics, too much power, less than adequate ergonomics and on and on kept ruling out gun after gun in the break-barrel class.

 Finally, I got to thinking - what were the characteristics that would make an ideal gun to suit the aforementioned shooting I had in mind.  I determined that the gun would need some significant mass so that it could be readily steadied from typical FT sitting and silhouette standing positions, yet not too heavy that it would be a burden to carry in the field or shoot in an extended silhouette match.

Immediately, what came to mind was the HW80 or Beeman R-1 as it is sold in the United States. Although the gun had a significant amount of mass to meet the criteria I set forth, the gun is no pea-shooter when it comes to springer shooting characteristics.  Even when custom tuned, this springer still packs a punch in terms of typical magnum springer recoil and report.

In thinking about this problem, I wondered if the gun could be tamed by putting a weaker spring into the stock unit.  A couple of quick calls to Russ Best and Jim Maccari helped me to learn that a significant issue in shooting springers accurately is lock  time or the amount of time it takes from pulling the trigger until the pellet exits the gun's muzzle.  In the springer world,  anything that decreases lock time is good, and anything that increases it is bad. Because increased lock time makes follow through more critical, one should always make modifications that neither affect lock time or improve upon it.  Both Russ and Jim indicated that a spring in the HW 35 class which produces less energy than an R-1 spring would probably make the gun a lot less harsh to shoot and easier to cock, but would be a tradeoff with increased lock time. 

This led me to a question for both Jim and Russ.  Could the increase in lock time be overcome by using a barrel of shorter length than the typical HW80/R1.  Both felt that this was a possibility and that by 'spacing up' an HW35 spring I might be able to build an adequate power plant, shed the harsh shooting characteristics of the gun, and at the same time have no real significant increase in lock time.  Also, Russ said that by 'buttoning' the piston that any increase in lock time from the weaker spring could be overcome by improved performance of the piston within the compression cylinder.

Armed with this knowledge, I decided to build a one-of-a-kind gun to meet my shooting specifications.  I dubbed it the HW80 WK or wimp carbine for the intended lower velocity than the stock HW80/R1.  Because I was dealing with a reduced velocity, I chose a .20 cal bore. In theory, this caliber should deliver more downrange power and be less susceptible to wind than a .177 cal pellet.  So off went a few initial orders - one to Specialty Shooting Sports in Canada for an HW 80 carbine in .20 cal, and a second order to Jim Maccari for a spaced up HW 35 spring and custom do-it-yourself Mirage Sporter.

While waiting on the essential elements of my 'project' to arrive, I began to plan on additional customization features for the gun.  These included a brass trigger guard from Mac-1 airguns, a Crow Magnum muzzle break and anti-cant bubble level from Airgun Express, a trigger shoe from Tyler's, BKL 30 mm scope rings from Silver Streak Sports,  and a 10X Super Sniper Scope from SWFA.

The scope choice deserves a little explanation.  For a while now, I have been a fan of the Super Sniper scopes. The scopes were originally built under government contract by Tasco.  When Bushnell acquired Tasco's assets, a decision was made not to continue the Super Sniper scope.  Recognizing a good thing in a rugged, dependable, mid-priced scope, the line is now produced and distributed by SWFA.  The Super Sniper scopes are solidly built with optics that rival scopes costing twice as much.  Also, the option of a rear or side wheel parallax adjustment has always appealed to me because fumbling with the objective bell while keeping on target has never been the easiest thing for me to do.

   As far as the choice of power  in a scope is concerned, 10X seems to be about right for me from a standing position as it keeps the target from swimming in and out of view due to my present ability to hold a gun steady offhand.  Because the Super Sniper scopes have mil-dot reticles, the need to do the turret twist thing during FT competition is eliminated.  I have found that once one really understands how to use a mil-dot in FT competition, it really decreases the need for a super-powerful scope.   If you don't believe all of this explanation for the lower-powered scope choice, then suffice it to say that Captain Bob agrees with me on it and encourages shooters to use lower powered scopes due to increased ease of use.  I usually do what Captain Bob suggests.  He is just such a good and successful shooter that it is hard to argue with him (on guns anyhow).

Time to assemble the parts and build the gun

After what seemed like an eternity, the parts slowly started trickling to my house via a combination of UPS brown trucks and US postal service.  Once the gun was received, I took 5 shots with it just to make sure it was in working order, then jumped into the car for the short trip to Russ Best's house.

The day I took the gun and the 'spaced up' Maccari HW 35 spring to get 'the treatment' by Dr. Best was the day he broke his lathe.  Those who are really into the airgun hobby will remember that day.  A busted machine at Russ's house means that everyone waits for their airgun tunes until the machine is fixed. In spite of the downing of a critical machine, Russ was in a good mood (he always is anyhow), and we covered exactly what we were going to do to the gun.   Russ suggested 'buttoning' the piston in addition to my plans for the gun.  Not wanting to appear like a total Yuppy Geek, I told him that I agreed that buttoning was definitely the way to go. Truth is, I had no idea what on earth he was talking about.  Buttoning shirts I understand.   Buttoning pistons might as well be building a new space shuttle.

When I got home the firs thing I did was a quick search of the internet for buttoning pistons  After reading about it,  I was very glad that Russ was going to do the buttoning.  Buttoning is a process where little tiny dots of very hard material like delrin are installed between metal surfaces to act like sliding bearings to reduce friction. Hey - that sounds like a good thing - something that would help to decrease friction and lock-time! Go for it Russ - Button Away!

The DIY stock

While Russ had the HW 80 in his shop getting measured for buttons and other things I am unqualified to address, the DIY stock came from Jim Maccari.   If you have never done a DIY stock before, and you have half an ounce of woodworking skills like me, you deserve to experience this process.  A DIY stock is a great way to save a lot of money over a custom-finished stock, and shaping the wood up and getting it prepared for oiling is not a difficult job at all. The HW 80 Mirage was the fifth stock I purchased as a DIY from Jim.  An evening with a small hand-held electric sander is all that it takes to get the wood nice and smooth.  Of the five stocks I have bought from Jim, not a single one has needed any attention in the inletting areas.  All were perfect fits to the airgun actions.

I find that the hard part of finishing a stock is getting a good finish on the wood.  My advice here is to prep the wood with a sealer, then resign yourself to a number of coats of Birchwood Casey's Tru Oil with plenty of sanding in between..  What I have learned in finishing is to avoid steel wool if possible and use equivalent synthetic abrasives that don't deteriorate as quickly as steel wool.  If you do go the steel wool route, make sure to give the gun a good visual going over between coats of oil to avoid having little pieces of steel permanently sealed into the stock finish.

The day after Russ called me to let me know my Button tune was done, I had completely finished the stock and all of the parts I needed to assemble the gun were present and accounted for.  Upon picking the gun up (and commenting that buttoning would surely decrease lock-time), I noticed that the gun, even though tuned down, had retained a considerable  report, and recoil in firing.  In a situation like this, the first thing I always do, is retreat to the basement with my pellet trap and just pump a few tins of pellets through the gun.   After about 300 pellets, the gun had smoothed out considerably, and the noise and recoil level declined to something similar to a tuned Beeman R-9.  This is not at all meant to be a criticism of Russ's work.  All guns, tuned or not, will benefit from a certain amount of break-in and this was certainly true with the HW 80 WK.  Anyhow - the thing is super smooth now thanks to Russ' magic.  What he did was put 1/4" PTFE/Delrin blend buttons onto the piston and adjust the JM kit for appropriate spacing and mass.

So far so good!  Next out came the chronograph.  Ten Beeman FTS pellets through the chrony confirmed a velocity of 730 FPS with a 3.5 fps variance.  Excellent!  My target was to have a .20 cal gun shooting Beeman FTS pellets at 700 fps. In my book, that's close enough to goal achieved!  After a short period of assembly of all the components, the HW 80 WK was ready for field testing.

The finished HW 80 WK

The stock was stippled both in the palm swell and forearm areas in a design that complimented gun's overall lines.  Note trigger shoe, brass trigger guard, bubble level, and 30 mm BKL mounts.

The Super Sniper scope mounted on the HW 80 WK

Note the large sized windage and elevation turrets.  Although they work with great repeatability and accuracy, I do not use them much due to the excellent mil-dot reticle on the scope.  Also, note the rear parallax adjusting ring.

Testing the HW 80 WK

My first real testing was done at 10 M with Beeman FTS.  Ten shots - one hole!  Good start, but, almost any springer could be counted upon to do that. So outside, I set the gun up for a 35 yard zero.  I was absolutely surprised when my first 5 shot group turned in an amazing 1/2" CTC group at that distance.  Out of curiosity, I took the target back to 48 yards (the longest I can go in my back yard) and the next 5 shot group was only 3/4".  From this, I was starting to feel that the idea of a lower-powered HW 80/R-1 in carbine just might be the ticket to an all-purpose gun.

To verify the ability of the gun to group, I set up five targets at 35 yards and shot five shots at each aiming point from a benched position. As can be seen below, the HW 80 WK produces great accuracy and consistency at 35 yards.

Conclusion

At present, it looks like the HW 80 WK is going to be a long-term resident of my gun closet.  Accuracy is consistently great, the gun is easy to cock, and it shoots and feels like a heavy R-9 - just what I wanted! Now on to the next project - learning how to shoot from a standing and sitting position to take full advantage of the HW 80 WK's capabilities!

DDay