Idiots guide to classic airgun strips (pt 1)

[Phil Russell]

CHINESE B5-3, maybe also known as the B45
I have a .177 version of this pneumatic pump up, 12 shot rifle from an auction bundle several years ago. It did not work; not a whimper. Fairly recently I was given a .22 version, again not working. This spurred me on to have a look at them. I did find an exploded diagram on the web but I admit it was not that much help. The action is not difficult to get into:
Remove stock; a screw at the trigger guard and another at the forend. Lift stock away but catch the trigger spring that sits in a recess. You won’t lose it as it is about 4cm long x 6mm diameter.
It took me several strips to find the easiest route to the bits. It helps to clamp the rifle in a padded vice but this is not absolutely necessary. There is no need to remove the pump assembly unless you are sure the pump is faulty .. if you need to do this, first remove the two small screws in the barrel end cap / sight unit. Then look at the cross bolt that goes through the cap. One of the screw heads will be a ‘keeper’ that screws into the end of the cross bolt. Remove it ,,, it is a 3mm thread … then drift out the cross bolt and remove the end cap. The pump handle is now free and you can pull the pump assembly out of the cylinder. I am not sure what you can do if the pump head is faulty as I do not know if spares are available. The head is a screw on type and it is possible that a unit from a Crossman could be adapted to fit. Re-assembly is a reverse of this. Add a lubricant … Pelgun oil.
With the action in the vice, trigger to right, there is another cross bolt at the rear of the action. This holds the hammer in place and there is no need to remove it unless you want to. To do so, remove the cross bolt, ‘keeper’ screw as before and the hammer mechanism will pop out a short distance. Pull the end block out, followed by the hammer spring and the hammer block. Note the groove in the end block; the cross bolt passes through this to keep the unit in place.
To access the valve, note the two screws alongside the 12 shot rotary magazine. Remove one of them .. each about 8mm long and then remove the other while holding the magazine in place. As the second screw releases the magazine housing will move back a little. Carefully remove it and catch the steel ball (about 6mm?) and the spring that sits in a hole in the action.
Look inside the action and note a retaining nut with a slot on each side. This needs undoing; I used some small needle nose pliers; easy. Remove the nut.
The valve unit parts can now fall out. Remove in order: a steel washer and the exhaust valve body that has a steel rod through the centre. Working from the barrel end, this valve body has a flat rubber valve seal on the rod, followed by a small steel washer and O ring around the rod. The washer and O ring sit in recesses in the valve body.
It is quite likely that the inlet valve has stayed in the action… pull it out gently. There will be a spring with a captive end piece and flat rubber valve seal.
On my rifles, various combinations of the valve seals and O ring needed replacement, quite clear by the splits present. Not being able to get original seals, I made some from 2mm thick rubber sheet. The inlet valve seal is 11mm diameter (wad punched) with a 1.5mm hole (leather belt hole punch) in the centre. It simply pops over a small peg on the captive end piece. The exhaust valve seal is 14mm diameter with a 5mm diameter central hole for the steel rod to pass through, again wad punched. My first attempt had the central hole slightly too small and it gripped the steel rod too tightly leading to a failure of the valve to work. The O ring in the valve body is, I believe, BS008.
To reassemble, drop the inlet valve and spring into the action, spring uppermost. Assemble the main valve body with the exhaust valve seal on the end of the steel rod, then the steel washer and the O ring. Put the steel rod through the valve body, making sure the O ring and small washer locate in the recess. Insert this unit into the action and add the large steel washer followed by the retaining nut; tighten the nut.
Place the magazine spring in the action hole followed by the ball then seat the magazine on top. Add the hammer housing and secure it with the two bolts. If you removed the hammer components, add the hammer, spring and end cap. Make sure the groove in the end cap allows access for the cross bolt; add the cross bolt and retaining screw. Replace action in the stock, do not forget the trigger spring and add the two stock bolts.
One of my rifles had an extra surprise. On top of the action was a threaded hole; examination showed it went down to the transfer port area. The other rifle had a screw plug fitted. I added a screw plug to this rifle. There was a similar hole on the underside of the action, this one clearly designed for a countersunk head screw. Again I plugged it. I have no idea what these holes are for.
This should be job done. From non working rifles, both mine are now healthy and three pumps gives a hearty crack as the pellet flies into the backstop. I have not tried four pumps or more as three seemed adequate effort.

Cheers, Phil

[Phil Russell]

I am adding this due to an interest in Collectables.
CROSMAN 2200 MAGNUM

Warning: taking this rifle apart is not difficult but putting the receiver components back together can be very fiddly, so if you are prepared to take the task on, give yourself plenty of time. Renewing the pump head seal is easy with no pitfalls.

Pump head seal: You need to remove the complete pump assembly, but there is no need to strip the receiver components. Remove the band that holds the barrel to the pump tube, one screw secures the two halves. Pull off the black cap underneath the band halves. There is a roll pin holding the pump rod link to the pump cylinder. Remove the pin. Remove a black plastic end cap from the pump cylinder tube and pull the pump assembly out of the cylinder. The pump head seal is a push fit on the end of the assembly ... part 760-140 (same part for the Crosman 2100, 760 and 766 and most likely other Crosman rifles). Reassembly is simply a reversal of these steps.

Parts inside receiver: To replace most receiver parts there is no need to remove the pump assembly. However, if you wish to service or replace the valve assembly or transfer port then you should remove the pump assembly as it makes handling so much easier.

To split the receiver halves, remove the three screws from the lh receiver side but keep the halves together. Place the rifle lh side down on a table and slowly begin to lift the rh receiver side up from the lh side. As you do this, watch out for the sear spring which will appear in the gap between the two halves just in front of the trigger housing. It is unlikely to ping away, but be prepared as it will almost certainly emerge through the gap as you separate the receiver halves. Continue lifting the rh receiver until it comes away over the cocking lever. You will be left with the trigger, sears, valve and hammer mechanisms in place on the lh receiver. All reassembly operations must be done with the lh receiver flat on the table, assembling the parts on this part before adding the rh receiver.

Lift away the little black plastic ring that holds the pump arm firm on the right side of the receiver. Do not forget it.

Lift away the sear spring mentioned earlier, noting that it locates on a peg on the underside of the sear bar. Lift away the steel right angled black part (trigger bar) sitting on top of the sear bar, then a washer, then the sear bar. There is no need to remove the trigger blade and the safety catch and catch spring. They will sit where they are quite happily.

Before continuing, look at how the pump tube and barrel assembly lies in the receiver; hopefully it will not have jolted free when you split the halves. Note the lh end hole in the pump tube and the black plastic part visible through the hole and the end of the tube. This is a spring guide for the hammer spring. The sides of this guide are flat and have a hole passing through them. One of the receiver securing screws passes through this hole. To access the valve mechanism, lift the barrel and pump tube away from the receiver. As you do this, the hammer and its spring will push the black plastic guide out of the tube, but they should not ‘ping away’. The hammer cocking lever and pellet probe assembly ... the black plastic bits that sit on top and rear of the barrel will lift away at the same time. The barrel and pump tube are not secured together and can be simply separated. No doubt the cocking lever parts will fall away as well but do not panic. Lift barrel off the pump tube. The transfer port should remain secure inside the valve housing that is in the pump tube. Remove the hammer, hammer spring and spring guide.

My valve housing, situated in the lh end of the pump tube, had a blow off valve fitted to the underside of the main valve housing; a brass cylinder about 12mm long x 8mm diameter dangling from the underside of the pump tube. It is a push fit in the valve housing so just pull it free. To access and service the valve mechanism you must push the valve (dowel will do it), towards the rh end of the pump tube; it simply pops out. Note the hammer pin at the lh end and a domed rh end with O ring seal. To access the inside of the valve, the rh end (domed) part unscrews but it may be tight. There is another O ring to seal this end part into the valve cylinder. Kits are available containing all the parts needed to service the valve, although if you suspect the valve itself is OK it may be worth trying just a new O ring on the valve body to give a better seal against the pump tube.
Look at the transfer port on the valve body; there should be a seal inside. Renew it if it looks worn.

Reassembly: When you are satisfied with the valve mechanism, replace it in the pump tube, apply a little Pelgun oil to the sealing O ring and push the valve back down the tube ... hammer pin to the left. Take care not to nick the O ring on the pump slot as you do so. Make sure the transfer port lines up with its hole in the tube. Now is a good time to replace the blow off valve, if fitted. Simply push it back into place under the valve assembly.

Place the hammer, spring and spring guide into the pump tube. Add the cocking lever components onto the top of the barrel assembly. Reassemble the barrel to the pump tube, making sure transfer tube on the barrel sits inside the port on the tube and that the peg on the hammer locates in the slot in the cocking lever assembly and that when you move the cocking lever to the left it takes the hammer with it. Get the lh receiver part, complete with stock attached, ready in front of you on the table. Now, hold the tube and barrel assembly in your right hand and with your left hand push the spring guide into the tube, making sure the flat sides of the guide are facing up and down so that when you push the guide into the tube you can see the hole in the guide through the hole on top of the tube. While holding the barrel and tube in position with the spring guide, lower the assembly onto the lh receiver such that the hole in the underside of the lh end of the tube locates on the peg in the receiver. It should go neatly into place, retaining the spring guide as it does so. It will, hopefully, stay put while you continue:

Replace the pin for the trigger sear bar in its hole, followed by the sear bar, a washer, and the right angled black trigger bar on top. The rounded flat section points to the top of the action, the side with a bent end goes on bottom left. Locate the trigger sear bar ‘sears’ into the slot on the underside of the pump tube. Now ... before you forget, replace the pump lever holding bit on the right side of the receiver. So far, so good. Now for the fiddly bits.

Replace the sear spring... over the lower peg on the sear bar and tucked onto the underside (bottom edge) of the lh receiver. Now slowly add the rh receiver part, keeping it flat as you first pass it over the cocking arm and then locate the lh side where it goes into the stock. Lower it onto the lh receiver side. Keep pushing down until the bottom edge, closest to you is just touching the top of the sear spring. You now need to push this spring back into the receiver as you continue to lower the rh receiver onto the lh one. Push it correctly and the receiver will come down far enough to hold the spring in place. I can now guarantee that the left hand side has become stuck because the safety catch is not locating in its hole in the rh receiver part. You need to get a small screwdriver or needle and tease the safety catch into position to allow the rh receiver to fall/push onto the lh one. Hopefully, as the receiver halves come together, the sear spring will take up its correct position in the receiver. But be warned: it is very easy to trap a coil or part coil of this spring as you bring the receiver halves together. Attempts to correct this by holding the receivers apart while you try to fiddle the spring into position are doomed to failure; the spring may come adrift of the sear or flip over completely. Far better to admit defeat and start again.

But, hopefully, you have succeeded. Now, holding the receiver halves together, cock the trigger and check it works (Do not pump air in). Success? Now add the central screw that holds the stock halves together. Try cocking and firing again a few times. If this fails, it shows that the trigger bar and sear bar have not seated correctly. The only cure is to start again.

If you removed the pump assembly, replace it along with the end band.

Job done ...

Cheers, Phil

[ggggr]

I got sent one of these not working last week---------didn't want it, don't want it but decided to look at it. This is the thing that looks like the Colt automatic and is very similar to the Marksmen version. A version is still being made and is sold by SMK https://www.gunspares.co.uk/products/24504/G10/
A search of Youtube will show you a strip---but this is more of the nitty gritty
If you push down on the cocking slide button and pull the cocking slide backwards, you should be able to pull put the little clip that looks like a bike chain split link, with a pair or long nosed pliers. You can then gently lever the slide out of the sides of the pistol and remove it. There are 3 screw on the RHS of the pistol that need removing before you can lift the RHS away. If you are unlucky, the mainspring unit will flt out and the trigger spring will flip up and out as well
Anyhow--if it doesn't, compress the spring unit from the barrel end towards the back (There is a little extension that locks the barrel so this end needs to come out first) and take it out. You can lift the sear off the trigger, remove the trigger, trigger spring and the safety (if they haven't already jumped out!). I'll deal with the piston mainspring unit at the end. They now come as a unit if you can get them.
To put the gun back together, replace the safety, then put the hairpin spring on the pin, replace the trigger and then tension the spring. The tricky bit is the legs of the hairpin spring need to cross over, so the bottom leg is pushed up above the trigger and locates on the bar for it on the trigger. Replace the sear on it's pin and make sure the other end is on the pin on the trigger. Now the difficult bit---replacing the mainspring unit in the frame!. Push the back of the spring into the housing and compress it enough so the prong on the thing that passes for a cylinder, will then go back to locate the barrel. In theory you should be able to drop the RHS of the frame back on and repalce the 3 screws. I spent 45 minutes doing it, chasing the springs round the kitchen. It was due to the unit being worn and kinked. I think if you got a thin piece of aluminium and bent it over you could keep the thing in place until the RHS was almost in place. Replace the slider then locate the rod bit of the mainspting unit in the slot and replace the spring link. You will probably have to pull the rod out with long nosed pliers first to make it easier.

On mine the rubber piston washer was split and you cannot get them on their own. I got a piece of leather and put it in warm water, then punched out a hole in it (took 2 goes to get the right sized hole that would stretch over the boss on the piston head, when wet. I then roughly cut it round while it was on the piston head and then squeezed it between my fingers to form it, then put it in a bit of tube to take the shape better, before putting it in the "Cylinder"! which is VERY THIN WALLED brass. It could easily deform, which is why I would suggest another bit of tube first. I was only doing this as you cannot get the piston washer. IN the morning when it was dry, I oiled it and fitted it. The pistol works and will fire pellets, darts or bb's in the repeater mode. They are very low on power, not that accurate and I've never been keen on bb guns/repeaters where you cannot tell if there are any left or not. Anyhow--if you have one, want to strip one, you are in with a chance.

[Shed tuner]

just done a vid for a stripdown of the park rh93 recoiless air rifle.. rh91 is exactly the same.

https://www.youtube.com/watch?v=lxms2G3JT8A


Will do the rebuild when I get 30 mins...

[Phil Russell]

HAENEL Mod III DRP
The rifle being looked at is a Haenel Mod III DRP. There number 11 30 is under the barrel near the breech block, which makes me think it is November 1930. Barrel also states Made in Germany. I found no other numbers.
Overall the rifle looks quite good with a firm lock up and little signs of wear anywhere. There was a small split to the underside of the stock extending from the cocking lever slot to the front trigger guard screw hole but this has now been glued. A first fire showed the rifle to be pretty smooth but with a bit of noise. Output was tested with .177 Superdome at 593fps / 6.5ftlb. A tissue test of the breech seal showed no evidence of escaping air. I felt a strip and service was required as performance should be a bit better.
Remove trigger adjuster screw, noting how far it is screwed into the guard. There should be a lock nut on it. This is necessary to access the front trigger guard screw which holds the stock to the action. Remove the front trigger guard screw. The rear screw is a wood screw into the stock so can remain in place. Remove the two screws in the for-end and lift action out of stock. Tap out the trigger pivot pin, noting the trigger spring being present. Take care to hold it as you remove the trigger and it won’t ping away. As the trigger end block has a retaining bolt I put action in a compressor. Remove the retaining bolt (9mm spanner). The end block screws out of the action and I had to use a small bar inserted in the trigger slot to set it turning. It needed little persuasion. To aid turning I used a punch through the holes for the trigger pivot pin. Not knowing the preload, I left the action in the compressor while I undid the block; spring tension was manageable at the end of the block thread but still present. Remove block (spring guide is attached) and the spring. To remove the piston I released the cocking arm from the breech block; a retainer screw plus a pivot screw. Lift cocking arm away. I could see no fault with the barrel latch mechanism so left it alone.
With the cocking arm removed, extract the piston. The leather piston washer diameter I measured was 29.5mm but had seen better times. It is retained with a screw and an inner leather washer into the end of the piston. At some time it had been fitted with a brass ring under the screw. This was badly corroded with blue gunk. Washer leather thickness was 2.9 / 3mm as a standard cup with c 8mm sides. I made a new washer, (using Neatsfoot oil as a soak during formation), ditched the brass ring and used another small steel washer to set the screw level with the outer edge of the leather washer to avoid a gap.
Looking inside the cylinder with a torch, I could see blue gunk at the end so cleaned it all out and gave it a quick polish.
I had previously found spring dimensions from Internet to be c 21.3 mm (0.84”) od, 3.27mm (0.127”) wire and 200.7mm (7.9”) long with 28 coils. The spring I removed was just about spot on these dimensions. I thought of adding a piston liner but judged the spring to not have sufficient clearance to do this. There was some scuffing on the rear edge of the piston which I polished out. I added a steel slip washer inside the piston.
Reassembly was a simple reversal of strip down. Piston with new leather washer was inserted in the cylinder using a few drops of SM50 on the washer as the piston went in. Piston body was lubricated with a smear of moly grease, as was the mainspring, spring guide and trigger block threads. Back into the compressor and the trigger block wound in until it was possible to engage the threads. When fully wound in, replace the block retaining bolt. If it gets stiff, stop and adjust the trigger block a tad. Replace the cocking arm; engage the end into the cocking slot, making sure the arm moves freely in the slot then fit the end to the breech block with the screw and keeper screw.
The trigger is then replaced. Put trigger spring in the trigger recess and then fit the other end into the recess in the rear of the block. These recesses are quite deep so there is little danger of the spring escaping while you manipulate the trigger down into the slot against the spring pressure. I found it easy to look through the trigger pivot hole to see when the trigger was in position then use a parallel punch to hold it all together while the trigger pivot pin was added. Make sure the trigger moves freely against the spring pressure. If not, remove pivot pin and try again.
Add a smear of moly to the cocking slot and the barrel release mechanism then replace action in the stock. Replace trigger adjusting screw. This acts directly to change sear engagement so do not screw in further than the screw was originally set. A test shot of the now very smooth serviced rifle gave one clearly ‘diesel’ shot but then settled down to a healthy 652 – 657fps for c 7.9 ft lbs. I expect this to improve slightly as the new piston washer beds in and settles down.
Cheers, Phil

[Garvin]

https://forum.vintageairgunsgallery....tol/#post-4252



LeonardJ provides these pics:





PS Len made these observations when he stripped a Hy-Score:

"One of the more unusual features, for any spring gun, is the presence of a lubricating wick on the piston head. The next thing that becomes apparent, in spite of being a concentric piston action (barrel runs throught the center of the piston), there is no seal present between the ID of the piston, and the barrel - just a very smooth, close tolerance hole through which the barrel passes - the lubricants form the seal. The piston head is fastened to the skirt of the piston in a manner that allows the head to "float" - no doubt to help maintain a seal. The spring guide also "floats" within the confines of the mainspring ID. The gun uses a common O-ring seal on the piston head, and a proprietary seal within the rear end cap, which seals the main compression tube, so that all the compressed air is directed to the breech, and thus to the pellet."

[Phil Russell]

Gem Style, no maker’s name. Most likely a model 13A from Eisenwerke Gaggenau (Iron Works, Gaggenau)
No. 57748 inside breech with numbers 748 or just 48 on other major parts. This rifle, .177, had been languishing in a cupboard for a long time. No makers name: overall 34” with 17.5” barrel, round but with a top flat. Barrel latch operated by a sprung lever on top of cylinder which, when pressed, allows the barrel to open.
Full of anticipation I tried a test shot; pellet only went about 1” down the, smooth, bore. Time for a service. I removed the screw bolt at the rear of the action near the front of the half stock. This pulls the sides of the cylinder together to nip on the thread of the cylinder / stock plug, holding the stock in place. Removing the bolt allowed the complete stock to unscrew from the cylinder; this gives access to the mainspring. There was a fair amount of preload, maybe 2”. When new I suspect the spring to be 8.25”, 37 coils of 2mm wire 15mm od. The rifle’s spring was about 1” shorter. Remove trigger guard /cocking lever by tapping out the pin at the front of the guard. Guard can now be removed to the rear of the action, bringing the piston with it. My trigger guard pin was bent so a new one was made from a suitable HSS drill shank. The piston rattled its way out of the cylinder. I was surprised to see a huge sealing washer about 9.5mm thick on the end of the piston. There was a steel washer secured by a peened over end to the central rivet rod, 8mm approx. diameter. There was no visible means of removal so I concluded the unit had been ‘rivetted’ into place. As I wanted to get the rifle working, I decided that a new washer would have to be fitted even if this meant sacrificing some of the old central rod/rivet. I decided not to attempt driving the rivet/rod out so removed the peened end to allow the end steel washer and piston seal to be removed. A new leather washer was fitted by tapping the end of the original rivet with a 4mm thread and screwing the new washer unit into place with a delrin spacer to give the same length of piston washer unit as original.
A new leather breech seal was fitted, 10.5mm od x 2.4mm thick with a 3.5mm hole punched in the centre. It is possible that the old seal could have been saved by a good soak in neatsfoot but I decided to do a new one.
The barrel release catch was a bit loose on its mount on top of the cylinder but after a failed attempt to tap out the pivot pin I decided to leave it alone: the pin was very firmly stuck and the catch worked OK as it was. Similarly I did not remove the trigger parts as I saw no need to. All are retained by pins. The trigger can be adjusted by a small screw on the trigger blade that adjusts sear engagement. It was loose so I put a drop of mild Loctite on it. I intended to remove the stock from its steel end plate but only one screw undid so I left it alone.
I lubricated and reassembled the rifle with the original spring and was pleased to see c. 340fps with Geco wadcutters and c. 320fps with AA Field. To satisfy curiosity I removed this original spring and tried a spring of the same specification that was about 1” longer. It made no difference other than being harder to fit. So I put the original one back.
All I all it was great fun despite the piston washer surprising me. I wonder if all gem style rifles are like this?
Cheers, Phil