.22 Sharp Innova, A Restoration Project. Fixing The Trigger And Sear

The sear block has a slight movement back and forth where it sits in it's housing, so to cure this I thought I would put a shim in there. Too thick and the sear would not return on its spring; too thin would make no difference whatsoever.

See how the back of the trigger pushes the sear block upwards?

So to start with, I tap the pivot pin for the trigger out most of the way until the trigger could be removed.

Gently tap out the pivot pin for the trigger.

With that done, the sear and return spring came out of the housing. 

This sear has different dimensions from the one that comes with the sear liner.

Then, with a small screw driver, I worked the metalplate out from an access point on the side ...

Unhook the steel liner from this point and out it comes.

... this is there to stop wear and tear on the plastic in the breach, this is L shaped with a a small tab to lock it in place.

The sprung steel liner stops wear and tear on the plastic of the breech

I cut a number of shaped pieces from thin plastic from a disposable food carton; these were placed between the metal and the plastic wall of the housing. 

I had to take the rifle apart to get the sear out as it was wedged in with too many shims, bloody nightmare that was.

I found one was perfect; when I tried two it was too tight and believe me it took a fair bit of effort to free the sear from where it had wedged itself in. So back to one shim and in went the spring ...

One thin plastic shim was perfect.

... the sear and then the trigger was lined up and the pivot pin was tapped back into place.

Line up the hole in the trigger and the pivot pin and gently tap in with a rubber mallet.

The trigger works fine now with no free movement of the sear back and forth, I could've got away without doing it but why the hell not?! Besides, you get to see how the trigger and sear assembly is put together.

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 

BSA Mercury, Friction in the Piston

And Finding The Most Accurate Pellet For a 70's British Springer

Out in the woods testing the .22 BSA Mercury.

I have done a far bit of tinkering with the .22 mercury, but i know it needs a little more. It's knocking out RWS Superdome's at 10.5 ft/lb then slowly dropping down to 9 ft/lb, this i'm sure is down to the tight fit of the rubber O ring piston seal. 

The new piston seal O ring below is a bit over sized.

 I've read that it's a common problem that the piston seal can be a little oversized when new, and i did have to use some force to push the piston into the compression chamber with this one. Most people usually put a tin of pellets through to wear the piston seal down, but i reckon in this case i would need nearer two tins of pellets before any wear is noticed on the O ring.

Repeatedly putting a 1000 pellets through the Mercury would get a little tedious to say the least.

My other option would be to dismantle the rifle yet again, and use wet and dry to wear the O ring down, i would need to turn the piston in the lathe and apply the abrasive to give it even wear, 

It doesn't look over sized when fitted on the piston head , but believe me it is.

Then i would size the piston now and again till it was just short of a sliding fit, so once the ruff edge of the seal had smoothed out after reassembly it would fit perfectly. 

I would rather avoid going through this rigmarole again.

My only concern for the rifle is for the thread on the breech block getting damaged with all this taking apart and reassembly, i also have a concern for the spring compressor because of the mighty preload.

These were good value and sorts out the problem of the scope rail dovetails being set too forward on the compression tube of the Mercury.

A 1970's .22 BSA Mercury has a barrel that is 5.6 mm as opposed to 5.5 mm that is more prevelent now a days, and the older pellets that were a tad wider are not available any more. Eley Wasps in the blue tin are sized at 5.6 mm but are crap compared to how they used to be, 

No 2 5.6 mm Eley Wasps are not the pellet they used to be.

i have found that RWS Superdomes fit just as well in the breech and are infinetly more accurate. So with this in mind i reckon it would be best to see how the rifle performs after i put a tin of Superdomes through it, at 7 quid a tin it sounds like the fun option to me and i usually take a second rifle with me when i go down the woods.

Accuracy

   I have found the Mercury shoots most consistantly with a light hold and supported by my off hand just in front of the trigger guard, from personel experience most springers are more accurate for me if i support them at where they balance and this is where the Mercury balances out. The trigger breaks lightly and cleanly with no first stage travel so it's easier not to pull any shot of target, both my BSA Meteor and the Webley Hawk have similar triggers to this so i reckon it must be some British thang.

Ready for the off.

Testing the accuracy in the woods means i can't test from a bench rest, but the results will be more indicative of how it will perform in a hunting situation. The rifle was sighted for 28 yards and i will test at 15 yards and 30 yards, and with the shelter of the woods i don't have to worry about wind effecting the results.

Resting the rifle, uncocked and unloaded, while i go of to check the target.

Using the large cardboard boxes that were left over from Christmas presents as targets i took Scatterbone down to the woods and paced out 15 yards, 

Handy large cardboard box left over from Christmas, inside is foam packing and a piece of ply wood, after a few tests i can stick targets to it with the Gaffer tape i always carry around with me. As i say," If counceling won't fix it, Gaffer tape will."

i shot from a sitting position with my back against a tree while holding the rifle lightly with my off hand supported on my left knee. Out of AA Diabolo's, Falcon Accuracy Plus, Eley Wasp's, and RWS Superdomes, i found the Superdomes to be the most accurate in the 5.6 mm barrel of the Mercury. 

RWS Superdomes in any caliber are the best all rounder in my opinion.

At 15 yards 6 shots came inside the size of a two pence piece with the Falcon's coming a close second, the Eley Wasp's were all over the place thinking i had lost my mojo but then the the Superdomes did it again.

I'm pretty happy with these results, cleaning the barrel and perfecting my hold will improve results no end.

I tried to test the Mercury out to 30 yards but it was pretty windy even in the shelter of the woods, with the wind push the pellets two inches over to the left. I managed to do some shots compensating for the wind and managed to get on target, but as it was i was well chuffed with the results of the 15 yard shots. Having put just over half a tin of pellets through the Mercury since i last tinkered with it i have found the best hold for me, being happy with that i reckon i should just put an other couple of tins through it till it beds in and the velocity rises and settles down. I really would like to keep this air rifle as the surge and recoil are quite mild and as a .22 it carries a lot of knock down power down the range, and above all it looks bloody sexy for an air rifle.

TTFN

Wing Commander Sir Nigel Tetlington-Smythe.   

Tuning the Norica Quick

Seeing as i was passing on the Norica to my mate i thought i would give it a bit of a tune up, besides i needed to drop the trigger pull a bit as well so kill two birds with one stone. Also it would give me a chance to see how the spring compressor would work out, i reckon there must be some preload as it is quite heavy to cock.

Preload is from the start of the wider trigger slot

The first thing i did was to check out the exploded view on Chambers http://www.gunspares.co.uk/shopdisplayproducts.asp?id=24977&cat=Quick, this makes life so much easier. Two plastic tabs either side of the fore stock revealed screws facing diagonally up into the cylinder block, and two screws on the trigger guard the rear one connecting stock to cylinder removed the stock. The safety latch was connected on to the trigger guard, pushed in place by the cocking linkage when cocked. The trigger unit held a nut for the rear screw and two pins held it in place to support a washer, spring guide, and the main spring. The rear of the trigger unit protruded from the cylinder by one millimeter and when pushed flush removed the two pins, however the unit could only be removed by pushing the washer and guide unit forward and slide it forward and out the wide long slot in front of it.

spring and washer pushed forward and trigger unit slipped out forwards

Handy device for removing trigger block and then letting spring and all free

I made a tool from two fat lengths of ali bar bolted to a half inch length of copper pipe which i hammered square, the bars would then fit between the outsides of the trigger unit and the inside of either side of the cylinder. With the cylinder supported on the spring compressor by using parcel tape of all things, i was able to wind the washer and guide forward two inches so i could tease the trigger unit out through the slot. Unwinding the pressure off the spring soon started to become a little alarming as the compressor was fully unwound and still under tension but i could push this by hand and slip it off, it would seem that this air rifle has four inches of preload and six if i included pushing it forward for removing the trigger unit.

Held down by loads of parcel tape

Handy device being slipped between trigger block and cylinder walls

I removed the guts or the rifle which was pretty dry except for a spot of oil behind the nylon piston seal, it all seemed in pretty good nick apart from where the piston had rub a little on top of the cylinder. however the end of the main spring had not been ground flat, and the sharp ends had left a ring of tiny marks on the top hat and the metal washer on the inside of the spring guide. The mainspring itself was in near new condition but where the sharp edges had nicked the tophat and washer there were minute flecks of metal scattered about, the piston was heavy with an inner sleeve which was a tube with cocking and sear latching cut into the outer layer.

Spring as it came out of rifle

Both ends ground down flat and polished

Right then, what did i do? Oh yes now i remember. First off i ground down flat both ends of the spring and gave them a polish, then  sanded the washer and tophat with wet medium then fine wet and dry' then polished with OOO wire wool the tophat, spring ends, and washer that all connected with each other. I then cleaned out the piston cylinder with white spirits and wire  wool on the end of a piece of dowel then polished and cleaned out any old crap left in there with a J cloth on the same dowel. Mmmmm shiney smooth. The piston was polished before the seal and at the end, and all deburring was done with my trusty Dremmel.

Heavy polished top hat and piston seal

this is one heavy piston i can tell you

Putting Abbey SM50 oil around the base of the piston seal and Abbey LT2 grease of around an inch at the end of the piston i slipped it back into the cylinder, LT2 grease on the end of the tophat and slipped that in the piston, the spring was then liberally coated in LT2 and then inserted making sure both ends had a tad extra grease applied was put in, then the spring guide and washer was smeared with a little extra LT2 grease and popped into the main spring.

Just some handy shit to have around for tuning

Before reversing the whole process of using the special tool to slip the trigger unit back into the slot in the cylinder i used the Dremmel to grind the sharp edges off the sear and piston, but only a little as i did not want to mess it up big time. Carried on putting the Norica back together and put the scope back on, which with the stop on it should not interfere with its previous POI.

spring pushed back in so trigger block can be replaced

Out in the back garden and took a five shot group, though sometimes i perfer a ten shot group. Anyway the trigger pull was down and there was most definately room to take more off, and the grouping was tighter and three inches above point of aim which means that it is now putting out more power. The rifle was also not so hold sensative, which i would call a successful tune indeed. What more could you ask for, i am indeed one happy little marsupial.

As i said i could lighten the trigger some more, but i shall leave that up to my mates discretion . Me personally, i would take it down a lot more but then i am used to being spoilt on Record triggers

TTFN

Best Wishes, Wing Commander Sir Nigel Tetlington-Smythe DOA OBE MBE FOAD