Saturday, December 12, 2009

Derrick's Daisy Powerline 1200 find

OK, it's been 11 degrees outside the past few days, so I've been procrastinating on the wood working projects in the garage. The Crosman 150 grips are gonna have to wait until I can at least feel my fingers out there.

Found this Daisy PowerLine 1200 CO2 pistol at the local gun shop for $15. Normally, I wouldn't bother buying a BB gun, but it looked like it was in almost mint condition. And how wrong can you go for $15? I knew I could at least get some blog material out of it and I can always threaten to send it to Nick. Besides, maybe it'll encourage the gun shop to keep taking airguns on consignment.

The real reason I bought it was that it appeared to have several shared parts with the second model CO2 pistol from Daisy--the semi-auto BB firing CO2 200. The model 200 dates from 1963 through 1976. Nick sent me a CO2 200 (actually about one and a half 200's were in the box) in about 40 pieces several months ago. I'm pretty sure he sent it as a joke. There are VERY few functional CO2 200's left and I think he knew I'd have to attempt repairs.

The original model 200 piercing assembly isn't compatible with current 12 gram CO2 cartridges and the valve seals are relatively complex. So, I was curious when I looked at the 1200 and saw how Daisy had added an end seal for the CO2 cartridge. I assumed the valve was different, too and wanted a look inside. While the model 200 is a true single-action semi-auto, the 1200 must be manually cocked before each shot. The model 1200 replaced the 200 in 1977 and was produced until 1996, it's as if Daisy went backwards in development.

Anyway, back to this 1200. I took it home and found a dead 12 gram cartridge inside as well as about 75 copper-plated BBs. A squirt of Crosman Pelgun oil along with a new gas cartridge and bang. It worked--uh, sort of. The gun fired--but sounded like it was a full-auto machine pistol. Braaaaaap. Unfortunately, it only fired one BB at a time. Had it truly worked in full auto, I'd have left it alone. I'd have probably even added a BB hopper for more ammo capacity. After a dozen shots, the gun worked and sounded as it should. However, a fresh cartridge brought the full-auto sensation back again for the first dozen shots.

"As is", indeed.

The cocking lever.

Left grip appears screwed in place--it's not. Find the finger groove at the bottom edge and lift up then pull off.

Right grip is screwed in place as is the forend. The grips and the rear sight are the extent of the plastic on the pistol.

This screw secures the grip frame directly to the valve assembly.

A slight back and down direction frees the grip frame. No need to remove the trigger springs or safety. (It may help to loosen the shroud screws shown below to make the grip frame pull free if it's stuck.)

Find a screwdriver that fits. The screws are threaded into the die-cast zinc valve body.

Two on the right side, and there's one on the left. (not shown)

The screw at the front of the shroud is different than the other 3.

The two halves of the shroud lift apart.

Black plastic bushing at the front provides a seat for the hammer spring. What? Yep. The barrel assembly is the hammer. When cocked, the barrel moves forward and compresses the spring. The sear catches and holds the barrel forward. Trigger is pulled and the barrel slams backward against the valve, valve opens and blasts the BB out the barrel. You've got to admire the design--there's a certain genius in it's simplicity.

Pin on the end of the barrel? It's the striker for the valve.

Ball bearing check valve. It's really that simple.

This is a 5/16" ball bearing.

Some kind of white synthetic seal for the bearing to seal against. Didn't remove it since it looked OK.

Went through the pellet pile and found several tins of lead shot. Figured I'd try to find the best fit to the bore. That should help with the mediocre accuracy that most BB guns deliver. Wish there was an easy way to add a rifled barrel to increase the accuracy with lead balls. I suppose a barrel could be turned down as one piece to include the base for the cocking lever and the spring seat, but you'd still have to cut a leade for the BB, drill a loading hole at the top, braze on a valve striker and add a pivoting wire catch inside the breech for the BB. I, um, decided to take a pass on all that.

The Gamo lead balls measured from 0.1750" to 0.1765".
The Beeman Perfect rounds looked exactly like the Gamos except they ran from 0.1760" to 0.1775".
And the Crosman Premier BB's were the smallest at 0.1710" to 0.1725".
Test fitting to the barrel indicated that the Gamo's were a nice snug fit. The Beeman Perfect Rounds were oversize and wouldn't even start in the barrel. The Crosmans were too small and rattled their way down the bore.

Maccari heavy tar on the spring to act as a damping medium. It's likely that the full-auto sound was caused by the barrel (remember, it functions as the hammer) bouncing off the ball valve, then rebounding from the hammer spring and striking the valve again--and rebounding against the hammer spring and striking the valve again and rebounding....get the idea? A slightly stiffer hammer spring would also probably solve the problem. Why is it a problem? It wastes CO2 so the shot count drops.

The trigger sear catches on this lip holding the barrel forward until the moment of firing. I gave it a dab of moly grease.

The sear is the pivoting silver bar above the trigger. The reassembly is the exact reverse. A very easy gun to disassemble with no mechanical complexity. Daisy tends to use the same parts for decades, so it's likely that Daisy will have seals available if needed.

I didn't install the plastic forend upon reassembly. It is necessary to install the forend bolt as it secures the front of the trigger frame to the upper shroud. One less piece of plastic on the gun and a cleaner look.

End note: Success! The full-auto effect is gone and the gun functions perfectly. Want it Nick?

Thursday, December 10, 2009

Haenel 311 Aperture Sight Disassembly

Well I found a small amount of time in the shop between work and decided to take apart the Haenel 311 sight for cleaning.

The sight.

Mounting block removed.

The underside.

The parts. Notice the flat cut on the screw.

Two screws in the face.


That shoe is just loose and under spring tension...

The Iris body unscrewed, but I couldn't get the stem to unscrew from the sight...

Neat little adjustable aperture setup.

The adjusting screws.

Both are left hand threaded.


Punching out the pins that retain the knobs in the body. Notice the finger below to catch the pin once I punch it out...

The knobs were a bit tight in the body...but just pull out when the pin is removed. Tiny spring and ball on each for the detent.

I chucked the threaded part of the eyepiece in some aluminum soft jaws and unscrewed the block.

This is one of the useful properties of soft jaws...

That post threads in and binds on the eyepiece.

All the parts. I have to wait for this cold snap to be over before getting much quality time in the shop...hard to do any work when your fingers are numb.

Monday, December 7, 2009

Crosman 150 Service

Bought a 2nd variant Crosman 150 (.22 caliber) at a gun show a couple months ago. Seller said it came from the estate sale of a former bullseye pistol shooter. Guess that explains the handmade target grips. Unfortunately, the grips fit my hand better than they fit the gun. The right side is a bit wobbly on the grip frame.

The 150 is notable because it's the first CO2 pistol from Crosman to use the standard 12 gram cartridge. It's essentially the father of the current 2240/2250 guns.

The Crosman website says the second variants were made from 1958 through 1968. If that's the case, the gun is older than me by at least a couple years.

Originally, the 150 would have come with a wrap-around brown or white one-piece grip. The trigger and trigger shoe are from my last project about a week ago. I did a super fast tear down a few weeks ago after a reader asked a disassembly question on the Pyramyd Airgun blog. It was late and I didn't have time then to take the pictures. I made the time tonight.

Unscrewed the end cap. Good, there's no CO2 in the gun.

Removed the grip panels--not a necessary step unless you're going swap the trigger spring.

Unscrewed the 2 grip frame bolts...

and the grip frame comes right off.

Don't lose the small safety spring and the ball bearing. They reside in the hole on the left side of the frame just behind the trigger. Ball goes in first, spring sits on top and pushes the bearing downward against the safety.

Removed the rear sight.

And the bolt comes right out. Not shown--the breech plug (small cap) pulls off the end of the upper tube.

Next, unscrewed the breech bolt screw and removed the breech cover (Crosman calls it a "loading sleeve") and the bolt.

Like so. Sorry. Blurry.

The hold down screw came next.

And the barrel/breech assembly lifts right off the gas tube. Don't lose the transfer port seal. A current 2240 transfer port seal is 100% compatible. Crosman part #130-036

This is the only trick. The "small tube plug" is pinned in place.

The trick is how do you get the pin out? The valve stem is in the way.

I used a transfer punch to push the valve stem forward toward the front of the gas tube.

With it pushed forward and braced against the workbench, I slid a pin punch through the hole above for the hold down screw and removed the transfer punch while keeping downward pressure on the pin punch. The pin punch slipped behind the end of the valve stem and rested on the top of the thrust pin..

A rap with a hammer and the thrust pin pops free.

"Small tube plug" and the thrust pin.

Note that the holes are offset in the tube plug. The offset goes to the front of the gun.

A piece of 1/2" plastic water pipe allowed pushing against the rear of the valve body without touching the delicate valve stem. Valve must be pushed forward to be removed.

Note the o-ring at the front of the valve. The early Crosman CO2 guns seal the cartridge in the tube. The new Crosman guns seal the cartridge only against the face of the valve.

A strap wrench unscrewed the valve body without marring. Some 150 valve diagrams show a few more components, but this is all I found in mine--a check valve spring, piercing pin, and valve stem. Clean and lube everything with pellgun oil.

When reassembling the valve, the threaded hole at the front for the grip frame must be 180 degrees from the exhaust valve hole. I installed the grip screw and sighted it against a transfer punch in the exhaust hole.

Lube the tube body o-ring on the valve and slide it home. Ensure that the exhaust hole lines up as well as the front grip frame threaded hole.

Like so.

Installed the front grip frame screw to keep the valve lined up.

Small tube plug--remember the offset faces forward--and the larger, unthreaded hole for the thrust pin goes on the bottom.

Seated the thrust pin and tapped it in gently with a small hammer.

Reinstalled the barrel/breech assembly (don't forget the transfer port seal between the tubes). Used a transfer punch to keep the rear holes aligned.

The rest of the reassembly was a straightforward reverse of the above steps.

Don't forget to lube the o-ring on the cap.
Before disassembly, the gun was working and I didn't want to risk damaging any of the seals by removing them to take measurements. If you need new seals for a Crosman 150/157,  call Ron at Bryan & Associates.