The “Mongoose” strikes… HW 80 -.22 -20ft lbs

A.G.R

Member
Jul 27, 2022
454
793
Usa
Ok, I’ve finished the HW 80 hunter I built (I’ll checker it after a month of drying) . I wanted to keep it stock strokes to try to see what it’s about..

( I’m working on a stroked version as I feel 5 mm more and it might be the best gun there is at it’s power, and stroke to cylinder ratio..more when that is further tested) It is a gun that’s built as good as it gets. When HW changed them front welded brackets witlh a spring loaded machined one that holds the arm tight at battery cocked. Along with the new cocking shoe. There IS NO AIR RIFLE that is as well built . Now it can benefit from some work as I have done. The factory seals are always parachute to support the guaranteed idiocy of the average shooter .
Remember, they are selling to mom and pop for jr. too. Not this type of airgunner.

This Mongoose has been reshapped in the breech block to match the chamber and sight screw holes filled with screws. I’ve welded them ,but you end up with heat transfer lines. I don’t mind the hairline screw lines . The best are the K breech blocks with none. The barrel was shortened to 11 inches. It has been recrowned and mildly choked with a full length shroud and … well it’s not empty in there.
I did do a slight bit of port shaping. Along with a new piston seal I made. (most Hw are tad smaller than 30 mm, 29.89.actually)
The spring is a smaller wire. .135… WHAT YOU SAY.. All them kit makers use .142 to .148 wire In their kits… It is easy to get a stout wire short stacked and tight wound to give a snappy cycle .. At THE COST OF YOUR ARM . Sadly the HW80 has a odd breech block to cocking arm ratio. It’s just out of what I refer to “the golden ratio” [I’ll post on that later, something I’ve found with the best guns for ease of cocking to power ratio. To breech block to arm ratio, THATS WHERE THE EXTRA 5 mm stroke will come into play]

The piston was carbonitrated,At the rear.. buttons are one way to center the piston . You need to indicate it and center the rod and re pin it with slip fit guide and it can’t move. The spring and guide are my own Designs.
The action and barrel have been bead blasted and reblued to a satin finish. It is a hunting weapon
The stock, yes ,I saved that for last.. it is a Venom inspired design from a local tree that was cut 25 years ago.. Its not my fanciest wood but sentimental , Yes.. it is a functional hunter stock. Albeit the front screws look like every Tx ,they are not. They are pillared with metal sleeves just under the wood to let the screws go flush while the metal braces against the machined brackets. (You could never get away with that ,with the welded brackets , they all stripped and you were re tapping and using cups in the stock) I prefer less outside,especially flush, to see the wood not brass rings or stainless steel

It’s shooting 14.66 ftt at 780 fps just a hair under 20 ft lbs with very little recoil. YOU WILL ALWAYS HAVE SOME,in a spring gun as it’s physics.. You can’t beat it. With the lighter spring cocking isn’t arm breaking like big wire. Trigger is ,well ,Rekord. 1 lb .

One thing I will be doing in the ne’er future is welcoming full open build specs as well as as much help as I can to those who want to try these builds on their own. I’ll tell you EVERYTHING IVE DONE. Remember, I can give you grandmas cookie recipe, not sure they will taste like hers.. 😆
I do not do this for any business or money as a tuning so called master or for profit. Been der done dat. Not worth it
Manny may be offended as they call balk and be offended because they think their knowledge s value, when in reality it’s fruitless . First ,it turns the many younger potential AIRGUNNERS away as they can’t afford these lustful guns. Give them hope and a bit of encouragement and we grow new AIRGUNNERS for the future of the sport..
Second, knowledge Is power, but what is knowledge if it’s not passed on..
Third, there is no money in truly tuning air rifles, the time spent on one gun that gives you fits can tie up a week worth of work.
TO THE GUYS WHO CAN MAKE $ kit dropping and de buring with new seals for $300 go for it..





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I love it. Wish I had the arena to tune and modify these in similar fashion. Maybe in the distant future I could see myself doing these types of things more and more. Passing of info or sharing is indeed of great importance and impact. At least for those willing to receive. I have a lot of questions, myself. I'd be very interested to see and understand the process or tuning this gun. Including the creation of parts as well as their modifications. And of course the why's. And what was gained. And how.
 
I love it. Wish I had the arena to tune and modify these in similar fashion. Maybe in the distant future I could see myself doing these types of things more and more. Passing of info or sharing is indeed of great importance and impact. At least for those willing to receive. I have a lot of questions, myself. I'd be very interested to see and understand the process or tuning this gun. Including the creation of parts as well as their modifications. And of course the why's. And what was gained. And how.
Thanks Long Gun … I’m very busy with real life job and other projects. Please feel free to ask what ever you want .. it’s a simple build that anyone with knowledge of taking a Hw 80 apart can do. It’s a very easy gun to work on.
 
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Ok, I’ve finished the HW 80 hunter I built (I’ll checker it after a month of drying) . I wanted to keep it stock strokes to try to see what it’s about..

( I’m working on a stroked version as I feel 5 mm more and it might be the best gun there is at it’s power, and stroke to cylinder ratio..more when that is further tested) It is a gun that’s built as good as it gets. When HW changed them front welded brackets witlh a spring loaded machined one that holds the arm tight at battery cocked. Along with the new cocking shoe. There IS NO AIR RIFLE that is as well built . Now it can benefit from some work as I have done. The factory seals are always parachute to support the guaranteed idiocy of the average shooter .
Remember, they are selling to mom and pop for jr. too. Not this type of airgunner.

This Mongoose has been reshapped in the breech block to match the chamber and sight screw holes filled with screws. I’ve welded them ,but you end up with heat transfer lines. I don’t mind the hairline screw lines . The best are the K breech blocks with none. The barrel was shortened to 11 inches. It has been recrowned and mildly choked with a full length shroud and … well it’s not empty in there.
I did do a slight bit of port shaping. Along with a new piston seal I made. (most Hw are tad smaller than 30 mm, 29.89.actually)
The spring is a smaller wire. .135… WHAT YOU SAY.. All them kit makers use .142 to .148 wire In their kits… It is easy to get a stout wire short stacked and tight wound to give a snappy cycle .. At THE COST OF YOUR ARM . Sadly the HW80 has a odd breech block to cocking arm ratio. It’s just out of what I refer to “the golden ratio” [I’ll post on that later, something I’ve found with the best guns for ease of cocking to power ratio. To breech block to arm ratio, THATS WHERE THE EXTRA 5 mm stroke will come into play]

The piston was carbonitrated,At the rear.. buttons are one way to center the piston . You need to indicate it and center the rod and re pin it with slip fit guide and it can’t move. The spring and guide are my own Designs.
The action and barrel have been bead blasted and reblued to a satin finish. It is a hunting weapon
The stock, yes ,I saved that for last.. it is a Venom inspired design from a local tree that was cut 25 years ago.. Its not my fanciest wood but sentimental , Yes.. it is a functional hunter stock. Albeit the front screws look like every Tx ,they are not. They are pillared with metal sleeves just under the wood to let the screws go flush while the metal braces against the machined brackets. (You could never get away with that ,with the welded brackets , they all stripped and you were re tapping and using cups in the stock) I prefer less outside,especially flush, to see the wood not brass rings or stainless steel

It’s shooting 14.66 ftt at 780 fps just a hair under 20 ft lbs with very little recoil. YOU WILL ALWAYS HAVE SOME,in a spring gun as it’s physics.. You can’t beat it. With the lighter spring cocking isn’t arm breaking like big wire. Trigger is ,well ,Rekord. 1 lb .

One thing I will be doing in the ne’er future is welcoming full open build specs as well as as much help as I can to those who want to try these builds on their own. I’ll tell you EVERYTHING IVE DONE. Remember, I can give you grandmas cookie recipe, not sure they will taste like hers.. 😆
I do not do this for any business or money as a tuning so called master or for profit. Been der done dat. Not worth it
Manny may be offended as they call balk and be offended because they think their knowledge s value, when in reality it’s fruitless . First ,it turns the many younger potential AIRGUNNERS away as they can’t afford these lustful guns. Give them hope and a bit of encouragement and we grow new AIRGUNNERS for the future of the sport..
Second, knowledge Is power, but what is knowledge if it’s not passed on..
Third, there is no money in truly tuning air rifles, the time spent on one gun that gives you fits can tie up a week worth of work.
TO THE GUYS WHO CAN MAKE $ kit dropping and de buring with new seals for $300 go for it..





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Personally i prefer the no checkering , I ordered an UK stock with no checkering for my HW97 / 77 , Love it that way , handle's wonderfully
 
Personally i prefer the no checkering , I ordered an UK stock with no checkering for my HW97 / 77 , Love it that way , handle's wonderfully
It’s a dedicated “ right “handed palm swell, thumb plate fitted FT type of grip. Your not loosing grip.. Its the Jerry Fisher in me. “A gun is not completed until you checker it” JF
 
It’s a dedicated “ right “handed palm swell, thumb plate fitted FT type of grip. Your not loosing grip.. Its the Jerry Fisher in me. “A gun is not completed until you checker it” JF
as long as you do not use that awful stippling crap . What a way to cheapen /ruin good wood . or even average beech stock .
 
Here are
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the seals I make. They are a clone of the Venom power pulse seals. This isn’t ” The” seal as that one is for a Tommy 27 mm mm tube but it’s EXACTLY the same design In 30 mm tubes. It’s not my design ,it was and is Venoms.. but in my testing and tuning there is no better. Your mileage may vary. There are more than one way to skin a cat. Vortek makes a similar VAC seal too..
 
Here are the two style of simple guides I use for center stem designs. Depending on spring OD. STEEL, 4140 , or Nylon6/6 infused with Molly ..Bronze is like buying Gold ,but works well too.. These Nylon guides are Natural and it comes in black too

I prefer to use a rear centering Bushing as it takes the load off the critical base area by dead centering the guide

When the spring allows it I lean towards Nylon as long as I’m not .062 or less wall thickness in the stem. Steel is predictable in any climate but has a distinct feel. They can’t be as tightly fit to the spring. A proper fitting guid in any synthetic should screw into the spring.. Steel is a magnet feel pushing it in.. To tight it will honk.

Doing the rear end plug does make you have to bore the rear block so it’s a bit more than some can do. That being said if you button the piston or ring , or even make sure it’s dead centered ,it you can get away with a flat 29.9 rear ring. Now ,I firmly use a stepped Delrin ring for strength to with a hardened shim washer for the spring to rest on the Nylon6/6

I took a picture of a typical steel washer guide ,TOP ONE in the pic of the three , with a flange to grab the delrin guide. I DO NOT USE THEM OR RECOMMEND THEM.
It’s not if , it’s when the spring will pull it through .. Your mileage may vary..

E52B5210-17C9-4965-B180-4140209F4681.jpeg
46DB1D85-911F-46E6-A4AF-A2F849E8B992.jpeg
60C2A5E9-A06B-486B-8F6F-52D4C5E9BDFE.jpeg

Top hats are spring centering devices inside the piston .. and sometimes you use steel to add weight to tame the cycle
nylon spacers are used too..
20BC3888-01FD-4822-BED0-4D8EE74459DB.jpeg


These are not the only way to do it and you can choose your own methods but consistently perform and have lasted well past 5k shots.

OK. HERE IT IS. .. 👍

The spring used was a Vortek .135 wire at 30 coils , with a .250 thick stepped rear nylon guide and a .300 thick metal top hat and a .400 nylon bushing.. The port was enlarged to .125 flared at the outer end and relieved with a tiny lead taper .030
9F24BB28-0958-49CA-8C0B-EE09AE6B9D37.jpeg
that’s another breech pickle fork face but that’s the idea .. The .125 helps the .22 breath a tad better and the tiny flare give a bit smoother feel to the cycle.
THERE IT IS. 19 to 20 ft lbs in .22 R1 that cocks easy shoots well and is doable ..
Now, here is the caveat.. This was done to a shortened barreled gun and results with full size may differ. As well as the top hat bushing size may have to be adjusted .060 +- as each action is not the exact same.
Do your dillegence and you will have a fine shooting hunting weapon.
 
Ok, I’ve finished the HW 80 hunter I built (I’ll checker it after a month of drying) . I wanted to keep it stock strokes to try to see what it’s about..

( I’m working on a stroked version as I feel 5 mm more and it might be the best gun there is at it’s power, and stroke to cylinder ratio..more when that is further tested) It is a gun that’s built as good as it gets. When HW changed them front welded brackets witlh a spring loaded machined one that holds the arm tight at battery cocked. Along with the new cocking shoe. There IS NO AIR RIFLE that is as well built . Now it can benefit from some work as I have done. The factory seals are always parachute to support the guaranteed idiocy of the average shooter .
Remember, they are selling to mom and pop for jr. too. Not this type of airgunner.

This Mongoose has been reshapped in the breech block to match the chamber and sight screw holes filled with screws. I’ve welded them ,but you end up with heat transfer lines. I don’t mind the hairline screw lines . The best are the K breech blocks with none. The barrel was shortened to 11 inches. It has been recrowned and mildly choked with a full length shroud and … well it’s not empty in there.
I did do a slight bit of port shaping. Along with a new piston seal I made. (most Hw are tad smaller than 30 mm, 29.89.actually)
The spring is a smaller wire. .135… WHAT YOU SAY.. All them kit makers use .142 to .148 wire In their kits… It is easy to get a stout wire short stacked and tight wound to give a snappy cycle .. At THE COST OF YOUR ARM . Sadly the HW80 has a odd breech block to cocking arm ratio. It’s just out of what I refer to “the golden ratio” [I’ll post on that later, something I’ve found with the best guns for ease of cocking to power ratio. To breech block to arm ratio, THATS WHERE THE EXTRA 5 mm stroke will come into play]

The piston was carbonitrated,At the rear.. buttons are one way to center the piston . You need to indicate it and center the rod and re pin it with slip fit guide and it can’t move. The spring and guide are my own Designs.
The action and barrel have been bead blasted and reblued to a satin finish. It is a hunting weapon
The stock, yes ,I saved that for last.. it is a Venom inspired design from a local tree that was cut 25 years ago.. Its not my fanciest wood but sentimental , Yes.. it is a functional hunter stock. Albeit the front screws look like every Tx ,they are not. They are pillared with metal sleeves just under the wood to let the screws go flush while the metal braces against the machined brackets. (You could never get away with that ,with the welded brackets , they all stripped and you were re tapping and using cups in the stock) I prefer less outside,especially flush, to see the wood not brass rings or stainless steel

It’s shooting 14.66 ftt at 780 fps just a hair under 20 ft lbs with very little recoil. YOU WILL ALWAYS HAVE SOME,in a spring gun as it’s physics.. You can’t beat it. With the lighter spring cocking isn’t arm breaking like big wire. Trigger is ,well ,Rekord. 1 lb .

One thing I will be doing in the ne’er future is welcoming full open build specs as well as as much help as I can to those who want to try these builds on their own. I’ll tell you EVERYTHING IVE DONE. Remember, I can give you grandmas cookie recipe, not sure they will taste like hers.. 😆
I do not do this for any business or money as a tuning so called master or for profit. Been der done dat. Not worth it
Manny may be offended as they call balk and be offended because they think their knowledge s value, when in reality it’s fruitless . First ,it turns the many younger potential AIRGUNNERS away as they can’t afford these lustful guns. Give them hope and a bit of encouragement and we grow new AIRGUNNERS for the future of the sport..
Second, knowledge Is power, but what is knowledge if it’s not passed on..
Third, there is no money in truly tuning air rifles, the time spent on one gun that gives you fits can tie up a week worth of work.
TO THE GUYS WHO CAN MAKE $ kit dropping and de buring with new seals for $300 go for it..





View attachment 429278View attachment 429282View attachment 429280View attachment 429279View attachment 429277View attachment 429281

View attachment 429276

View attachment 429283View attachment 429309View attachment 429310
Here are the two style of simple guides I use for center stem designs. Depending on spring OD. STEEL, 4140 , or Nylon6/6 infused with Molly ..Bronze is like buying Gold ,but works well too.. These Nylon guides are Natural and it comes in black too

I prefer to use a rear centering Bushing as it takes the load off the critical base area by dead centering the guide

When the spring allows it I lean towards Nylon as long as I’m not .062 or less wall thickness in the stem. Steel is predictable in any climate but has a distinct feel. They can’t be as tightly fit to the spring. A proper fitting guid in any synthetic should screw into the spring.. Steel is a magnet feel pushing it in.. To tight it will honk.

Doing the rear end plug does make you have to bore the rear block so it’s a bit more than some can do. That being said if you button the piston or ring , or even make sure it’s dead centered ,it you can get away with a flat 29.9 rear ring. Now ,I firmly use a stepped Delrin ring for strength to with a hardened shim washer for the spring to rest on the Nylon6/6

I took a picture of a typical steel washer guide ,TOP ONE in the pic of the three , with a flange to grab the delrin guide. I DO NOT USE THEM OR RECOMMEND THEM.
It’s not if , it’s when the spring will pull it through .. Your mileage may vary..

View attachment 429467View attachment 429466View attachment 429481
Top hats are spring centering devices inside the piston .. and sometimes you use steel to add weight to tame the cycle
nylon spacers are used too.. View attachment 429480

These are not the only way to do it and you can choose your own methods but consistently perform and have lasted well past 5k shots.

OK. HERE IT IS. .. 👍

The spring used was a Vortek .135 wire at 30 coils , with a .250 thick stepped rear nylon guide and a .300 thick metal top hat and a .400 nylon bushing.. The port was enlarged to .125 flared at the outer end and relieved with a tiny lead taper .030 View attachment 429492that’s another breech pickle fork face but that’s the idea .. The .125 helps the .22 breath a tad better and the tiny flare give a bit smoother feel to the cycle.
THERE IT IS. 19 to 20 ft lbs in .22 R1 that cocks easy shoots well and is doable ..
Now, here is the caveat.. This was done to a shortened barreled gun and results with full size may differ. As well as the top hat bushing size may have to be adjusted .060 +- as each action is not the exact same.
Do your dillegence and you will have a fine shooting hunting weapon.
Thanks for sharing your knowledge sir. Excellent write up!
 
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