BUD­GET HUNT­ING OUT­FIT

Did Pete Evans man­age to bring in his BSA Light­ning sporter project on bud­get?

Airgun World - - Contents - PETE EVANS

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.

SPE­CIAL TOOLS

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.

NEW TRICKS

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.

COM­PRES­SION TIME

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.

DE­RAILED

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 RE­BUILD­ING

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.

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