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hw80 barrel change, help please

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H

hunkaluv

Member
Oct 11, 2015
67
15
qc, Canada
Hi all,
I've got a brand new hw80 (.25) that i immediately short stroked and installed a .20 barrel on. (Didn't even shoot the .25 barrel, just went right into tune mode.) I was hoping to achieve 12fpe and i did by cutting a few coils and adding the TBT short stroke kit. It cocks super easy, and is smooth shooter. The .20 barrel wasn't very accurate with the 3 different pellets i was able to find (at 12 fpe anyway) so i've since switched it over to a .177 barrel. It didn't take long to find a couple pellets that are accurate. Here's the issue:

The breach block on the .25 and .20 barrels measure 18.64 mm in width, and they fit in between the (not sure of the terminology here) forks of the compression tube without any issue. The .177 barrel though measures 18.84 mm and i can only fit one of the thin pivot bolt washers in. I've installed it with only one washer just to check operation and accuracy. I've oiled the breach block lightly and it doesn't seem to be galling where the one washer is missing. What i had noticed when i first removed the .25 barrel is that the forks from the compression tube seemed to bent in at the side closer to the compression tube (IE probably pinched to fit the 18.64mm .25 barrel), though i never measured it.

So what should i do?
Continue shooting it and monitor for galling?
Attempt to open the forks to make more room?
Mill the breach block on the .177 barrel to fit the forks better? (I don't really have the tools for this, it would mean a trip to a smith.)
Other options i'm not aware of?

Thanks in advance,
Ryan
 
I'd want the pivot shims in there. It will wear the bluing off the side without it in short order.

Where did you acquire these different barrels? Maybe the .177 is a different vintage? Weihrauch changed some things around 2012, and that may have been one of them.

If you do get "serious" don't have the breech blocked milled thinner. Instead use an aircraft counterbore and machine pockets in the breech for thicker pivot washers. Paul Watts has a Youtube video showing how he does it. I do it on FWB 124s to help their piss poor weak lockup issues.

Making sure the forks are square would also be step #1. Measure the gap at the bottom of the forks, and make sure it's even all the way to the ends. If not, you can bend them back true. Also take the measurement at the bottom of the forks and then add up your shim washer thicknesses, and see what the breech block width "should be" to fit and work well. It should be obvious then which barrel is the one it wants.
 
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Thanks Capt and Thumper,
The 177 barrel is from a 2012 hw90. I'll measure the forks, but i'm pretty sure by eye i could see they were wider at the tube side. I noted it but didn't think it would be a problem as i had already fit that same .20 barrel on my hw90.
Thanks again for taking the time to reply.
Ryan

PS no rush Capt, i won't be able to get to measuring until end of day tomorrow anyway.
 
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One barrel 177 - 1992 is 17.83mm
One barrel 20 - 2019 is 17.70mm

Your current 0.2mm difference is a little less than 0.008" you should be able to splay the forks with the barrel to get the second shim in there. The shims are about 0.004" each. I had a friend's R7 that the forks were very tight and it made working on the gun difficult. Basically I just pulled on the barrel to separate the forks enough to get the shims in place. I used a wooden BBQ skewer to push them in place. Make sure there's plenty of moly on all the parts. After the shims and barrel are close to in place, center the left side shim and barrel with the skewer through the bolt hole, put the lubed pivot bolt through until it hits the misaligned right side shim. Center the right side shim with the skewer through the bolt hole, turn the screw with your fingers to start the thread. If it doesn't start try pivoting the barrel while turning the bolt. Don't force the thread you'll bugger the shim or the fork. You may have to back the bolt out and try to realign the shim with the skewer again.
Good luck.
Fwiw the Hw90, 80, 85, 95, 98 barrels are interchangeable. I've swapped all of them at one point or another. They use different length bolts and diameter shims based on piston diameter. But they will all interchange.
Ron
 
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Mycapt65 said:
One barrel 177 - 1992 is 17.83mm
One barrel 20 - 2019 is 17.70mm

Your current 0.2mm difference is a little less than 0.008" you should be able to splay the forks with the barrel to get the second shim in there. The shims are about 0.004" each. I had a friend's R7 that the forks were very tight and it made working on the gun difficult. Basically I just pulled on the barrel to separate the forks enough to get the shims in place. I used a wooden BBQ skewer to push them in place. Make sure there's plenty of moly on all the parts. After the shims and barrel are close to in place, center the left side shim and barrel with the skewer through the bolt hole, put the lubed pivot bolt through until it hits the misaligned right side shim. Center the right side shim with the skewer through the bolt hole, turn the screw with your fingers to start the thread. If it doesn't start try pivoting the barrel while turning the bolt. Don't force the thread you'll bugger the shim or the fork. You may have to back the bolt out and try to realign the shim with the skewer again.
Good luck.
Fwiw the Hw90, 80, 85, 95, 98 barrels are interchangeable. I've swapped all of them at one point or another. They use different length bolts and diameter shims based on piston diameter. But they will all interchange.
Ron
Click to expand...
Thanks Ron. I like the BBQ skewer idea. I usually use an awl to help centre it, but the skewer would definitely be gentler. To splay the forks, you just used the barrel itself? Did you leave the pivot pin in place? I had thought to check the straightness of either side with a straight edge along the compression tube, then maybe use an open ended wrench (plus some protection) to massage it into place.
Thanks so much for doing that, will let you know how I get on tonight.
Ryan
 
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Don't try to open the forks with a wrench. Leave them alone. Trying to spread them permanently may misalign them.

I didn't have the pivot bolt in place when I wiggled stuff in place. The pivot bolt will hinder your leverage on the ears. You'll have to fiddle with it. IIRC I had the compression tube horizontal and the barrel approximately down at a right angle. I levered the forks just enough to drop the shim in the open side from the top. Only one shim should be really difficult. Make sure you remember to hook the cocking arm into place first. Use the BBQ skewer to push the shims into close position. Then use my instructions from my earlier post regarding their alignment and pivot bolt installation. Don't hesitate to message me for my phone number if you need help. Typing these type of explanations is tough for me.

Good luck
Ron
 
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You'll have a tougher time if the center of the shim is deformed by centering them with the bolt or awl. Once deformed you can't really flatten them again. I usually keep new shims on hand. Flat shims are easier to install and they aren't expensive. Also if the tip of the skewer splinters when pushing on the side of the shim from the resistance, switch to a popsicle stick. You need to use wood or plastic as not to scratch the metal. An old credit card might work as well.
 
Upvote 0
hunkaluv said:
Hi all,
I've got a brand new hw80 (.25) that i immediately short stroked and installed a .20 barrel on. (Didn't even shoot the .25 barrel, just went right into tune mode.) I was hoping to achieve 12fpe and i did by cutting a few coils and adding the TBT short stroke kit. It cocks super easy, and is smooth shooter. The .20 barrel wasn't very accurate with the 3 different pellets i was able to find (at 12 fpe anyway) so i've since switched it over to a .177 barrel. It didn't take long to find a couple pellets that are accurate. Here's the issue:

The breach block on the .25 and .20 barrels measure 18.64 mm in width, and they fit in between the (not sure of the terminology here) forks of the compression tube without any issue. The .177 barrel though measures 18.84 mm and i can only fit one of the thin pivot bolt washers in. I've installed it with only one washer just to check operation and accuracy. I've oiled the breach block lightly and it doesn't seem to be galling where the one washer is missing. What i had noticed when i first removed the .25 barrel is that the forks from the compression tube seemed to bent in at the side closer to the compression tube (IE probably pinched to fit the 18.64mm .25 barrel), though i never measured it.

So what should i do?
Continue shooting it and monitor for galling?
Attempt to open the forks to make more room?
Mill the breach block on the .177 barrel to fit the forks better? (I don't really have the tools for this, it would mean a trip to a smith.)
Other options i'm not aware of?

Thanks in advance,
Ryan
Click to expand...
Not to be negative Ryan,
Why buy a heavy HW80S and de-tune <12 FPE, when a HW95, HW35E or HW50S would make more sense?

I wouldn't mill the breech block or bend the forks, but would look into getting a correct sized .177 barrel. You really should have 1 shim on each side.
 
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Mycapt65 said:
Don't try to open the forks with a wrench. Leave them alone. Trying to spread them permanently may misalign them.
Click to expand...

If they aren't even from bottom to top, they are already misaligned..

Spreading the forks is easier than you'd think. I use an old breech block clamped in a vise, slip the tube over it vertically, and pull towards you. Doesn't take much.
 
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One reason for the variation in width on the older breech blocks is they were hand finished "flat". That's why the bluing worn off under the shims isn't always even, it's not entirely flat.

The newer guns are machined flat, so should have much tighter tolerances as far as width.

I'd want the forks true and square and even in width if it were my gun. Fix it right once, or band-aid it forever.
 
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The distance in between the forks is 18.05 mm at the compression tube side, 18.03 at the pivot side...so it is slightly misaligned.
My 177 barrel measures in at 17.95 mm and the shims are .10 mm each. Obviously my 177 barrel is a touch wider than the norm, whereas my .25 and .20 are both around 17.66 so they fit fine. I'll try the Capts suggestion first (gotta jiggle it, we'd say at work) and if that doesn't work i'll think about letting the shims in as per Thumper's FWB trick.
Thanks everyone for your replies, so nice to have such experience to draw on.
Ryan
 
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SpiralGroove said:
Not to be negative Ryan,
Why buy a heavy HW80S and de-tune <12 FPE, when a HW95, HW35E or HW50S would make more sense?

I wouldn't mill the breech block or bend the forks, but would look into getting a correct sized .177 barrel. You really should have 1 shim on each side.
Click to expand...
Hi Spiral, no worries i asked myself the same question when i bought it. I have an FT stock for my HW90 which will fit an HW80 with minimal tweaking. I have a HW50 and have soft tuned it, but it's still hard to cock and only puts out 8fpe. I also have a 97 which is set up for FT, but i find it to be too front heavy which is why i'm playing around with break barrels. I enjoy the tuning as much as the shooting, so it's really just a project rifle.
 
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hunkaluv said:
Hi Spiral, no worries i asked myself the same question when i bought it. I have an FT stock for my HW90 which will fit an HW80 with minimal tweaking. I have a HW50 and have soft tuned it, but it's still hard to cock and only puts out 8fpe. I also have a 97 which is set up for FT, but i find it to be too front heavy which is why i'm playing around with break barrels. I enjoy the tuning as much as the shooting, so it's really just a project rifle.
Click to expand...
Hey hunkaluv,
You should be able to get 10 or 11 FPE out of you HW50S. Macarri spring and a spacer. I even buttoned the pistons; my two are at 10 & 11FPE using 7.87 grain AA pellets. I could have gotten 12 FPE, but it was too harsh for my liking....

ARH-1.JPG


ARH-3.JPG
 
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SpiralGroove said:
Hey hunkaluv,
You should be able to get 10 or 11 FPE out of you HW50S. Macarri spring and a spacer. I even buttoned the pistons; my two are at 10 & 11FPE using 7.87 grain AA pellets. I could have gotten 12 FPE, but it was too harsh for my liking....

View attachment 275506

View attachment 275507
Click to expand...
How's the cocking effort? Mine was 12fpe out of the box, but very boingy and not fun too shoot. I've got a PG4 kit in it now, but had to cut lots of coils to get the cocking effort down to reasonable, which left me with 8fpe. Still a nice shooter and i even made an FT stock for it. I originally bought it for my dad to shoot FT with but it's probably the rifle i reach for the most often at the moment.
 
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