Saturday, April 10, 2010

Reanimating a HW80K, Part 3

On I go...

Checking the barrel with a straight edge. My friend Jim had visted earlier and looking at the rifle felt the barrel was belt to the side. I saw this as well...

It does seem as though it's bent. But that shouldn't necessarily cause an accuracy problem?

Playing around I was pulling in the barrel. At the juncture of the top of the barrel with the breech block I saw a thin line.

And when I pulled up on the barrel a line of grease appeared (hard to see). This is odd and while I'm certainly not an expert as far as I know the barrel should not be loose in the breech block.

Only one thing to do...I pressed out the well hidden pin that locks the barrel in the block.

It's countersunk.

But the flared over end straightened out.

Pressing out the barrel.

It was straight knurled.

The grease I wiped off of the knurled portion.

And the grease I wiped out of the breech block.

So at the end near the muzzle end of the breech block it is .6279" dia.

In the middle .6332"

At the breech end .6342"

The hole is tapered from .632" at the breech end... .636" at the muzzle end. So the hole is too big and tapered and the barrel too small and tapered. Thus it was only really anchored by the breech end. This would certainly cause some trouble with accuracy?
I can only guess as to why the barrel is in this condition.

Obviously there's more to come...

Friday, April 9, 2010

Reanimating a HW80K, Part 2

On I go...

I mounted the action in my spring compressor.

Unscrewing the end cap. (loosen cap, loosen compressor, repeat)

The end cap comes loose.

Just a little moly grease...sigh,

Loosening the pivot scew & nut. I had gloves on at this point because everything was coated in moly.

The hemispherical slotted nut is cool.

Yes, that's moly on the screw.

There are shim washers between the block and the fork. And a little more moly.

Pivot screw, nut and the two shim washers.

The cocking shoe that slides along the piston.

Slightly overlubed. Notice the trend yet?

The piston. Hmmm...

That doesn't look like the HW seal I just received from Maccari...some furious googling resulted in this post from the UK airgun BBS and this pic of a similar Venom piston with o-ringed head. Well it should work fine.
I forgot to mention that I did put the rifle over the chronograph when I had it together before. It was shooting 14.3gr. CPs at 760 fps. The HW80 new is supposed to be at about 800 fps according to Pyramyd and 760 according to Airguns of Arizona, so I'm getting ballpark results of about 18 ft/lbs. And this is the HW80K, K being for Karbine as it has a shorter barrel? So in any case that o-ring likely works well.

The piston is sleeved as well. I couldn't get that pin retaining the head out.

Removing the drunken screws from the cocking handle/muzzle brake...

And the barrel is chewed up.

Did I mention the spring was coated with tar? Not heavy tar but seemingly actual tar as used in asphalt roads.

Still so much more to come...

Thursday, April 8, 2010

Reanimating a HW80K, Part 1

A reader of the blog offered me his HW80K for a reasonable trade. He said he was never able to get it to group right which is odd considering the reputation the HW rifles have.

He shipped it in this impressive crate.

A "Venom" sticker which, along with the "Hull Cartridge" stamping on the barrel, means it came from the UK. Venom are known for their tunes so I had high hopes that the rifle would be a diamond in the rough... as it turns out it was more rough than I expected.

I slapped the rifle together...just so I could show the complete disassembly.

Unscrewing the forward stock screws.

Hmmm, one screw hole is all wallowed out...

And the screw is bent?

Two screws on the triggerguard.

And back.

That bit done.

The Rekord trigger unit...

So the mounting tabs on the tube are crudely welded and one is at least 1/8" out of line with the other. This explains the bend screw and wallowed hole. In Tom Gaylord's R1 book he mentions the tab on his first R1 (which is largely the same as the HW80) breaking off. So at some point the tabs must have come loose and were rewelded.

Welded by a drunk and myopic monkey. Yikes. Well that's project #1, getting the screw hole back to where it should be.

Two pins hold the Rekord trigger unit in the rifle.

Pin one.

Pin two.

Two pins.

When you lift out the trigger unit the safety wants to come loose.

The trigger unit was smeared with oily moly grease. On the outside. Which makes no sense.

A bit of preliminary cleaning...

The safety spring was hiding inside the end cap.

Safety and spring.

Much more to come...