BUDGET HUNTING OUTFIT
Did Pete Evans manage to bring in his BSA Lightning sporter project on budget?
Last month saw me buying a classic rifle with a view to getting it into field-worthy state, all on a paltry budget of £100. Initial examination disclosed a number of obvious faults; damaged breech washer, excessive movement at the breech jaws, and inconsistent power delivery. In a situation like this, it is quite likely that further faults will be manifest on a full internal examination – a sobering thought when you have little scope for cash injections, in this case £30, given the original purchase of the gun for £70.
To be fair, as a back garden plinker it would be quite useable as found, but as a potential hunting gun it would need to be grouping pellets tightly at the designated range. The Lightning has good potential as a hunter, and this was my target, as well as trying to keep to budget.
I needed a round section of metal or wood with a diameter of 25mm, around 60mm length, with a 14mm slot cut through the centre. My own tool started life as a bath tap, and being brass was easy to work and fashion into the desired shape.
One other item I would count as very useful for the job would be a spring compressor, and in this case the humble sash cramp is the ideal solution.
GETTING THE SCREWS TURNING.
The stock is held in place by two hex-head screws in the fore end, and one screw accessed through the trigger guard. I would advise against using ball-ended hex keys to remove the fore-end screws. The ball end does not allow much engagement with the screw head, running the risk of ‘rounding’ the head. Use the plain, parallel-sided short end to loosen; after this, the ball end is safe to use. It will be noted there is a star lock washer on the trigger guard screw.
I have a little ‘trick’ that can save a bit of effort when you remove and replace the barrel. It will work on other BSA break barrels, too.
Owing to the fact that the barrel had a bit of lateral wobble, it was concluded that it would be a good idea to replace the barrel-retaining pin. The barrel pin also secures the barrel latch, which means that if it is knocked out, the barrel comes out and so does the latch – under its spring pressure – which is particularly difficult to replace when you are trying to line up the barrel and drift the pin back in. However, there is a solution:
Use the new pin as a punch to drive out the old pin. By doing this, you just replace one pin for the other and everything is still secure. Now take the old pin and cut it to 12mm in length, slightly shorter than the width of the breech block. Use this small pin to drive the new pin out, but stop midway so that the pin ‘sits’ in the middle of the breech block,
keeping the latch in place, but allowing the barrel to be removed once the cocking linkage is pulled up and its end disengaged from the cocking slot.
To remove the latch, hold and depress in a vice, push out your short dummy pin and slowly release the pressure.
Clean the latch and spring. If the barrel lock-up seems a bit weak, a little pre-tension can be applied to the spring by adding a couple of suitable size washers behind the spring. Put a thin coat of molybdenum grease on the latch, compress in the vice and replace the short dummy pin to lock everything ready for reassembly. The breech washer was well past its best, with fragments of plastic hanging off, but a sharp seal pick aided its removal and the replacement simply pushed back into position.
After removing the plastic cylinder end cap, take out the hex screw from the back of the Maxigrip scope rail and remove the location plug. Rest the action in the sash cramp. Position the newly made tool so that it bears on the spring guide, yet straddles the large retaining pin. Apply the pressure. When the spring guide is compressed, the retaining pin will get loose whereby it can be pushed out, DON’T push it out with your finger – use a punch, a stick, anything but your finger – for obvious reasons.
Take the spring tension off slowly, and the guide and mainspring should now be free to remove.
On examination, the spring was straight, and hardly shorter than a new one, so a few pounds saved there. However, the guide was a fairly loose fit.
The easiest way round this was to use a set of Delrin spring guides at a cost of £20. These will help to protect against spring buckling, and dampen resonance.
Before the piston can come out, the Maxigrip scope rail needs to come off. This subject causes much angst among the airgun fraternity, but it needn’t. The alloy rail is attached to the cylinder by interlocking lugs, kept tensioned by rubber cushioning strips. To remove, pressure is needed at the front of the rail, pushing it back and thus releasing the lugs from the cylinder.
In practice, this was achieved by using a piece of soft-wood quadrant, the curved section over the cylinder, a few sharp taps on the end of this wooden drift soon had the rail off.
The rubber strips were in good order, as were the retaining lugs – all very helpful for the budget.
It is possible to remove the piston without taking the trigger apart, but as this was a full rebuild, I thought it made sense to get
everything apart for inspection.
Start by drifting out the trigger stop pin, and then move to the trigger strut pin. When you look down into the trigger mechanism, you will notice two springs; one bears on the trigger strut, the other the top sear. You need to release the tension on the top sear spring by simultaneously pressing down on the protruding ‘tongue’ of the spring and then pressing out the pin. All the remaining pins can now be removed. I would advise snapping some pictures as you go, to aid reassembly.
The piston can now be slid out. If I were a betting man, I would put money on there being a worn piston seal because the piston moved back a little too easily. There needs to be a degree of friction present to form an airtight seal.
GET THE MUCK OUT
Guns don’t need much grease inside. Excess lubrication can lead to dieseling (combustion of oils) resulting in high, but unpredictable power. My own gun was a little heavy on the lube, so a bit of time degreasing with some choke and carburettor cleaner (remember those things?) was in order.
Once all clean, apart from the piston seal, all looked in good order. Despite the piston having a plastic liner, the spring was a little loose inside. A steel liner was made from a drinks can which made things a better fit. It’s not good to have too close a fit because the spring expands as it compresses.
The piston seal is relatively easy to remove by levering it off with a screwdriver. It seems to be easier in the warm weather due to the softening effect and this could be mimicked by standing it in hot water. Replace by simply pushing back on. This is easier by pushing it directly onto a hard surface until it clips into place.
Get a little molybdenum paste around the edge of the piston seal, a little on the wider sections of the piston, and push home. Take some care not to snag the new seal on the cocking slot.
The trigger is be replaced in the opposite order of disassembly, making sure the springs and sears are the correct way round. A little non-silicone machine oil is sufficient here.
Before replacing the Maxigrip rail, apply some grease to the rubber pads to make it easier to slide on.
Place it in position, a little downward pressure with a clamp can help the lugs engage with the cylinder, if they don’t engage, drifting it back can bend them. Tap it slowly back into place until it regains its former position.
The spring can now be replaced following a light coat of grease, if required. Some like to run them dry with synthetic guides.
The cylinder should now go back into the sash cramp to compress the spring. Be careful to keep the cocking slot in line with the slot in
The Lightning overhaul has finished, but did it break the budget?
Sear spring in the centre tensioned by cross pin. Press on the small protruding ‘tongue’ whilst pushing the pin out.
First step is to remove the trigger stop pin, best accessed from the safety side.
Remove the trigger strut pin – nothing to go ‘boing’ yet!
This gives an overview of trigger components and relative position.
A clamp helps to keep things together before drifting the rail back on.
Some gentle persuasion rearward with a soft drift, gets the rail off.