.22 Mk I Sharp Innova, A Restoration Project. Adjusting The Pump Rod And Blow Off Valve

The pump head - when the pump rod is at rest on any multi pump - should ideally just touch the face of the outside of the air inlet valve, inside the pump cylinder. Most leave a little space which, when the rifle is fully pumped, is compressed air and will want to expand, pushing the rod back if the gap is too large. However the length of the pump rod can be adjusted on the Sharp Innova very easily indeed, which my friends is very handy for so many reasons.

To remove the pump rod for adjustment for either stroke length or pressure blow off adjustment, first remove the front sight unit. Knock out the front roll pin, then pin with circlip on it and the unit pulls off the front as well as the pump arm dropping free. 

As I had been removing and refitting the pump arm so much I used a clear plastic bag between punch and pin to avoid the possibility of scratching the blueing.

Next, pull the rod back by the pump arm linkage, and tap the pin holding them together through the same hole the pin and circlip go through; this leaves the pump rod free to be removed out the front of the pump cylinder. Tease the link end out with something, then it just pulls out.

Just used an old bent pair off tweezers to push the pump rod out this time.

The brass unit on which the actual pump head sits is the pressure blow off valve, and the 10mm silver nut behind this is the lock nut which holds the unit in place on the rod. Crack the 10 mm nut loose by supporting the end of the blow off unit with a 14 mm spanner.

If the lock nuts are too tight, use a pair of mole grips on the valve body, it's pretty rare to resort to that though.

With a 10 mm spanner, loosen off the lock nut for the blow off valve unit and pump head.

10 mm lock nut loosened off.

By hand I screwed the blow off unit and pump head about 2 mm outwards to bring the pump head nearer the inlet valve, reducing the amount of pumps needed to make full power. Remember, if it is adjusted too far the rod will bend eventually as it will be too long, so do it in small increments, reassembling and testing each time until you are happy.

The thread on the rod and the thread on the blow off valve run in opposite directions, which does make things a lot easier.

Then tighten the 10 mm lock nut to keep the pump head in place on the rod.

Tighten that lock nut back up.

For adjusting the blow off valve, use a 14 mm spanner to loosen the brass lock nut at the base off the blow off valve unit; the thread runs the opposite way to the thread on the rod so you can use the 10 mm lock nut for leverage.

The lock nut for the blow off valve is actually a ring with two flat edges opposite each other.

If you need to up the ft/lb before the blow off valve kicks in, screw the brass unit inwards, likewise adjust it outwards if you need to lower the full power output. There is a very strong, thick, square section spring holding back the air inlet seal in the blow off valve, so you might need some mole grips or something to adjust the unit inwards.

Screw to the right or inwards to up the power and to the left or outwards to drop the power, it was fine as it was in this case.

I didn't need to adjust the blow off valve this time so I left the valve alone and tightened the brass lock nut back up.

And retighten the blow off valve lock nut to keep the power where it is.

With both lock nuts tightened up, I carefully inserted the pump rod back into the pump cylinder, being mindful of the pump head as it passed any open metal work on the cylinder.

A dab of silicone oil around the pump head makes this go a lot more smoothly.

Reattaching the pump arm is simply a reversal of the removal process; the brass bushing on the pump arm had slipped out a little and had to be hammered back into place before I could get it to fit in the cylinder and sight unit.

I will never understand why they go to the trouble of fitting brass bushings then scrimp on the breech by making it from plastic, still they stand the test of time anyway.

Tapping the roll pin and stud back in with a rubber mallet is always better than using a hammer.

Rubber mallets also vastly reduce the chance of scratching the bluing or paint work.

And do be careful fitting the circlip as it's a bitch to find if it pings off somewhere.

Anyway, that 2 mm adjustment reduced the the 12 ft/lb blow off limit from 7 pumps down to 5 pumps, it is possible to reduce it down to 4 pumps but I didn't want to chance over doing it and having the rod eventually bend.

Now all I had to do was remove my Deben Whisper silencer which I had used for testing over the chronograph.

The Deben adaptor always gets stuck in the sight unit, not scratched it yet though.

And it was all ready to be sent back to it's owner. I am well chuffed to hear he was very pleased with the work I had done for him, it almost made me feel like i actually knew what the hell i was doing (joking!).

TTFN

Best wishes, Wing Commander Sir Nigel Tetlington-Smythe.

Practical Pistol Shooting kit and Other Unprofessional Bodged Bits and Bobs.

I own two .177 steel BB pistols at present, both are blowback and field strippable. One is the Swiss Arms G92 which is a pretty good copy of the real steel Taurus G92, which is itself a copy of the Baretta 92, except for the safety being on the frame and not the slide.

A pretty good copy of the Taurus G92, except for the mag extention which allows space for the CO2 bulb.

The other is a licenced copy of the Sig Sauer P226 X Five, the basic P226 has a shorter barrel and no beaver tail. This is an extremely comfortable pistol to hold and fire.

The Sig P226 X5 fits my hand a treat

Since I bought the Sig P226 X Five BB pistol i've been getting into a bit of speed shooting or pratical pistol, and it is a real hoot i can tell you.

There is a high feeling of realism with this pistol.

I bought a spare magazine when I found one in stock because they are not that common.

Spare mag for the X Five, grab them when you can.

 I decided on a leg holster which I got off E bay for about a tenner, it velcros around any pistol and has a mag pouch as well. What I didn't notice until too late however was that there were no locking buckles for the two leg straps,  however I found an old bum bag with the right size buckles on it, so off they came and the holster was fixed.

Drop thigh holster would work loose around my leg with no retaining buckles.

Easily fixed after salvaging a couple of buckles off an old bum bag.

I like the pistol on my thigh for a quick draw as I can have my arm relaxed down the side of my body with the pistol grip easy to grasp,

Hand ready to draw, spare mag pouch at the front of the holster.

this gives me time to draw, 

With the restraining strap released, the gun lifts smoothly from the holster.

rack the slide as it comes up my body, 

Finger of the trigger till you're ready to fire, after this you can use your own one or two handed grip.

then perfect a two handed grip  as I push the pistol forward while aiming by focusing on the front post sight.

Next, I knocked up a load of metal target plates that angle down slightly so BB's rebound downwards and not at me, 

The steel plate rings out louder because it is suspended by wire.

well not at my face at least! They tend to be 3 by 4 inches and either made from aluminium from old DVD player casings and the like, 

Aluminium makes more of a thud when hit by steel BB's.

or steel from old heater covers which ring out when hit unlike the ali which makes more of a thud.

Different metals and quality allow for different range of sound when hit.

I really like the Three Gun style of competition shooting where you shoot set targets with either a pistol, a shotgun or an automatic rifle in whatever order the course demands. I have a shotgun, MP5 and H&K G36 in 6 mm airsoft, ideally I would like an airsoft M4 gas blowback and use my Crosman 1077 as the automatic shotgun as it is a smooth bore afterall.

The Airsoft G36 is the orange and black one at the end, it's the only pic I have of it at present.

The Crosman 1077 makes an excellent stand in for an automatic shotgun, but at over 5 ft/lb you have to be extra careful about your backdrop.

The fun is in the doing rather than showing on this blog, and it really is a lot of fun. I have a small woods I have permission to shoot in, so I set up different courses by hanging the metal plates from branches and seeing how quick I can run through them. Well, it keeps me happy.

TTFN

All the best, Wing Commander Sir Nigel Tetlington-Smythe

.22 Mk lI BSA Airsporter, A Review

The Airsporter was first sold in 1948 as the MkI; it wasn't until 1959 that the MkII came out with the addition of two short wide scope rails. Both of these models were the only ones to have the loading tap open automatically when the rifle was cocked, after that the quality slowly started dropping off on the later Mk's.

Mk I BSA Airsporter, bloody sexy.

The Airsporter is a tap loading underlever spring piston air rifle, and the awesome thing about the underlever part is that it is hidden from view in the underside of the stock, making it look like a sporting firearm rifle. The BSA Mercury is a break barrel that is identical in looks, but was not introduced until the MkI in 1971, by which time the Airsporter was at it's MkV stage. Even the old BSA Cadet has similar looks, though is a totally different design. They all have the smooth swept back look from the rear of the piston cylinder to the comb of the stock, instead of a step.

.22 BSA Mercury with scope, .22 BSA Airsporter and a .177 BSA Cadet, sharing a common heritage.

The big thing to remember about old BSA air rifles is that the bore of the .22 was actually 5.6 mm and not 5.5 mm, so they tend to be very pellet fussy when looking for both power and accuracy. Old Eley Wasps worked well but not the new ones, however RWS Superdomes tend to fare well in my experience.

The front sight has four interchangeable elements of different heights with a bead on top. The sight element is secured with a small screw from the left hand side. This sits atop a sloped ramp with a hood around it, though in this case there is no hood and just one of the taller elements.

Beaded sight elements come in low, standard, medium and high and are secured with a small screw.

The rear sight is of a leaf or butterfly design that flips up and down and sits in a dovetail in a sleeve around the barrel, just in front of the loading port. The unit is drifted in the dovetail for horizontal sight correction.

Rear leaf sights using the V notch at the moment.

A small notched plate secured by two small screws sits between the leaves and has a small amount of vertical adjustment, it can also be fitted upside down giving you the choice of a V or U notch to sight with.

The other option is to fit a scope, which can be done. The piston cylinder has two sets of short scope rails each set 13mm wide, this means a scope will be a little off centre with modern mounts but adapters or special mounts can be bought.

Early, rudimenary scope rails, better than nothing but still a bitch to fit modern mounts on.

To cock the rifle you have to pull down the spring loaded catch at the end of the cocking arm at the front of the fore stock,

Sturdy spring loaded catch holding the underlever arm flush to the fore stock.

this allows the cocking arm to drop a little so you can pull it back 120 degrees until it cocks. 

Underlever arm at full cock magically opening the tap loading port, Harry Potter eat your heart out.

The sweet thing about the MkI and II models is that there is a cam that automatically opens the loading port when the rifle is nearly fully cocked. The loading port can't be closed until the cocking arm is returned and locked in place.

When this air rifle grows up it wants to be an Air Arms Prosport.

This is handy in my mind as there is less of a chance of the rifle being dry fired. It's not 100 percent foolproof, but the loading port lever is pretty noticeable and you would have to be pretty well distracted (a polite way of saying idiot!) if you forget to load a pellet before returning it home, where it sits nice and flush in a small cutout in the stock.

As the loading tap only ever needs to be pushed down it can sit flusher than others.

It is definitely an adult air rifle as the cocking arm is fairly short and gives the illusion of pulling the piston back as opposed to pushing; the underlever linkage does not connect directly to the piston, but to a a rail that slides along the underside of the piston cylinder.

All the metal inside the stock is the slide that allows the linkage to push the piston backwards.

The rail system also triggers the cam for the loading port and pushes the piston on cocking, it is held against the piston cylinder by a plate and a nut.

 The nut and plate that keep the slide against the piston cylinder.

The plate also holds the cam and the guide holes for the single screw bolt and nut that holds the fore stock side panels in place. When I first saw the bolt side of the stock, I thought someone had bodged it and broke one of the two screws I mistakenly assume were used. No, just one nut and screw bolt running from one side to the other.  

The stock itself is made up of three seperate pieces of walnut, the butt and pistol grip and the two side pieces - seeing as the cut out would be for the cocking arm as well as the trigger housing it's just easier to make it in parts.

Looking very carefully you can see where the pieces of fore stock are joined to the rest of the stock, from just in front of the serial number, out a bit, and sweeping back just past the rear of the trigger guard.

At first glance it looked like a very clever and professional fix, but again I was wrong. The butt has no shoulder pad and is finished off with a shallow curve with horizontal ridges cut into the wood, the forestock has finger ridges carved down both sides. This is all very common for it's age and looks very shapely, although there a few scuffs and marks which again is not uncommon for a rifle this old.

I took the rifle into the shed and put it over the chronoscope. Using 10 Superdomes at 14.5 grains I was getting a 500fps to 509fps spread, with one odd one at 540fps which I ignored. This converted to 8.3 ft/lb, not to bad for an old air rifle. A couple of drops of oil will soften the leather piston seal and the muzzle velicty should improve, and would do even more so with a new piston seal, main spring and lube.

That's it for now.

TTFN

All the best, Wing Commander Sir Nigel Tetlington-Smythe. 

.22 Mk l Sharp Innova. A Restoration Project.

I've been doing this blog for about three years now and admittedly, not a lot has been going on for the last few months if the truth be told. The usual reasons really; work, family and being a bit of a lazy git. Anyway, the other day I got an email off a chap who has read my blog entries on the Sharp Innova and asked if I could restore his for him, to which of course I said yes as us airgunners tend to help each other out if we can. We exchanged many emails back and forth and several weeks later, Parcel Force delivers the gun - minus the stock - to the door.

.22 Sharp Innova, Whisper Silencer. Rhino blocks, and a Tasco 3-9x50 scope.

The Innova on first inspection appears to pump up and hold air just fine, however on dry firing, if the trigger is released slowly there is a slow release of air then the rest is dumped through the valve. So the first order of the day is to strip her down and get the valve apart to get a look at the trigger and sear. I have O rings I can use until the proper kit arrives from T R Robb, but it would be handy to see if anything else has buggered up in there and needs ordering as well. Externally, the rifle is in a really tidy condition and it's owner has had it for the last 30 odd years from new, so it sounds about right that the O ring seals would be starting to perish by now.

The piece in the middle is all i need.

And this is what arrived in a long cardboard box, wrapped in a metric fuck ton of cellophane. Considering the breech and outer barrel are plastic, there is some weight to it!

I removed the pump arm pin by sliding the circlip out of the way, then pushing out the pin.

The circlip needs to removed with great care as they are a bugger to find if they go pinging off somewhere

Next I removed the roll pin that holds the front end sight unit on, making it possible to remove the front unit that holds inner and outer barrel and the cylinder. 

Roll pin is pretty firmly held in place, but a punch does the trick. Note the pellet tin in the backdround for keeping small bits from getting lost, very important.

To remove the pin that holds the pump arm to the end of the pump rod, simply line it up with the pump arm pin hole at the front end of the cylinder and push it out. You have to tilt the pump rod slightly for the pin to come out.

 The hole for the front end of the pump arm is drilled below centre, so the pin for the swing arm and pump rod sit above this and don't fall out.

The whole pump rod assembly will now come out with the help of a screwdriver, the whole thing was slathered in thick black grease which was not right at all. 

There should not be any grease on a multi pump , just a couple of drops of moly oil here and there.

There was so much that if it was on a main spring on a break barrel air rifle it would have most likely knocked four ft/lb of power off it! You only need three drops of moly based oil now and again to keep the pump arm lubricated. This was going to be interesting! When I got the valve unit apart, it took a lot of kitchen towel to remove the gunk, it got everywhere.

I later recycled this grease for the bearings on the back wheel of my bike.

Remove the brass collar then unscrew the stud to loosen the cylinder with valve inside it.

There is also a trigger adjustment screw that pushed the trigger away from the underside of the breech block, it's missing, just like every other Innova i've come across.

The cylinder came out of the breech easily by sliding the cylinder spacer out by it's little lip, then sliding the tube out, being careful of the transfer port O ring on the top side.

The transfer port O ring seal sits atop the cylinder, removing the spacer lets it come in and out without catching on anything.

This one did not have the nut and screw that presses the tube up into the breech hole like the last one I had did, but seemed to be a really snug fit with the spacer in place regardless. The exhaust valve back guide on the back end of the cylinder unscrewed by thumb pressure alone ...

Looks like you could get or make up a little tool to remove the back guide,  but they tend to move if you use your thumb.

... then out came the spacer, bumper, bumper plate and exhaust valve spring. The exhaust valve came out by unscrewing the brass collar, then removing the screw under this that secures the valve to the correct part at the rear or the cylinder, which has already been done.


I pushed the valve unit out with a piece of dowl; if the pump arm is connected, draw the arm back securing the valve in place with a drill bit then remove the drill bit and pump the arm slowly. The valve will slide out under pressure, but remember to catch the firing pin as this tends to shoot out and get lost somewhere in my experience.

Bumpers, spacers and springs keeps the firing pin in check when fired, I have known many Innova's with the bumper and plate missing. Easy to bodge up and replace if push comes to shove.

I unscrewed the firing pin housing from the valve body by holding one part in a vice and unscrewing it with the help of a wrench, it was on bloody tight but shifted in the end. It only needs to be firmly hand tight as the O ring between the two holds the air pressure in. Again, it was pretty much packed full of grease.

I removed the valve spring and inlet valve ball, then unscrewed the inlet seal stopper. I left the inlet seal in for now as it seemed fine and I was just concerned with cleaning out the grease. 

Grease inside the exhaust valve. Inlet seal and stopper are still inside the body, you'll see them in a later blog when i fit the new seal kit.

When it came to cleaning out the firing pin housing, once the pin was removed I found it was missing the exhaust valve seal and seal washer. It would appear that the only thing holding what air pressure it did hold was the copious amonts of grease. I was going to have to get a washer made up as there was none in stock on any of the spares sites.

The O rings are old ones I had in a tin, so where is the the O ring and brass washer to support it?

A couple of hours later, I was checking to see how far the firing pin went into the housing to see if an old O ring would do the job, when I noticed the pin wasn't quite reaching the O ring. I gave the firing pin housing an extra clean up and noticed that the O ring washer was actually wedged into the housing (that was a relief!), but that the O ring seal was missing, which would explain a lot.

I found the washer wedged in there, the O ring is one I took off an old Innova I worked on ages ago. Needless to say it was buggered.

Seeing as I had to wait for the O ring kit to arrive before I could sort the valve out, I thought I would check out the trigger and sear. I had noticed the trigger adjustment screw was missing which is pretty common in my experience. Tapped out the trigger pin and removed the trigger, out came the sear and the sear spring but no sear liner.

The sear goes the other way up and the spring pushes the rear liner back after each shot, where is the sear liner? I reckon I could knock up a new liner out of a bit of thin flat bar and a tiny grub screw to see if there is any improvement.

The sear sits in it's space in the bottom of the breech unit. The spring sits in it's hole in the sear and pushes against the liner, which moves up the sear when the trigger is pressed. A hole in the liner lines up with a hole in the sear allowing the firing pin to be released. At least that has been the case on the other Innova's i've worked on!

In this case, the sear is upside down with the spring between it and the roof of the sear space, in the breech, the trigger is pushing the sear up until the firing pin can shoot through the hole, allowing air out the valve and on it's journey through the transfer port. In theory this should work fine and hopefully is not the reason for the slow escape of air when the trigger is pressed gently.  If it is, I can fabricate a makeshift liner and if that sorts it I can then order the part. I will just have to play the waiting game for now.

There's refitting the seals, sorting out a sear liner and adjusting the air let off valve on the pump head to come, so that's another couple of blogs in the works.

TTFN

All the best, Wing Commander Sir Nigel Tetlington-Smythe