Modding BSA Lightning XL trigger

[TonyHolden]

My BSA has a very nice two stage trigger, it may be a bit heavy for some people but I love it.

[Hangtight]

Tony, I have to say that the polished one I tried was much nicer than mine. Actually the rifle as a whole was nicer to shoot, smoother and with less recoil. I think I was struggling with the pull weight and consequently gripping too tight and pulling shots consistently low and right especially if I was practising quick target acquisition and getting the shot off without hesitation. This may have its origin in an elbow injury, which is the reason when I shoot with a mate of mine we fight over who gets the BSA Ultra and who has to lug the HW77! Have to say, I love the way the Lightning XL handles, and if a bit of time and effort will turn it into something a bit special, then I'll do it just for the satisfaction.
So, seeing as the fiddling has started does anyone have any suggestions for possible modifications? 'O' ring it? Shorten the stroke? I've got a tame machinist and it will make a change from drag race engines

[TonyHolden]

Tony, I have to say that the polished one I tried was much nicer than mine. Actually the rifle as a whole was nicer to shoot, smoother and with less recoil. I think I was struggling with the pull weight and consequently gripping too tight and pulling shots consistently low and right especially if I was practising quick target acquisition and getting the shot off without hesitation. This may have its origin in an elbow injury, which is the reason when I shoot with a mate of mine we fight over who gets the BSA Ultra and who has to lug the HW77! Have to say, I love the way the Lightning XL handles, and if a bit of time and effort will turn it into something a bit special, then I'll do it just for the satisfaction.
So, seeing as the fiddling has started does anyone have any suggestions for possible modifications? 'O' ring it? Shorten the stroke? I've got a tame machinist and it will make a change from drag race engines

I found that I instinctively use a thumb up grip and pull the trigger back into the ball of the thumb. It seems to line up nicely along the axis of the rifle and not disturb my position, that could be down to the shape of the tactical stock though...

[Hangtight]

While waiting for the postman I compared some pics of the XL SE with the Tactical. The Tactical has a very upright grip with a nicely curved laid back trigger, while the SE has a more relaxed wrist to the stock and a very straight trigger blade. I use a thumb up grip too, but with the straight blade it feels like you're always putting a lot of effort into maintaining finger position on the trigger.
Sitting staring at the letterbox is not very constructive, so I've put together a compressor and just need to make something to reach over the pin then it's coming apart for a clean up and fettle. 29mm dia bore, 80mm stroke with a 2mm dia transfer port? Been having a read through the Airguntech site (very interesting), and this seems a bit cockeyed to me. Any ideas?

[Hangtight]

The Lightning is now pulled apart, and all is not good Bear in mind this is a virtually brand new rifle with about 500 pellets through it.
The first thing you notice is the almost complete lack of lubrication. None, nada. The next thing you notice is the fact that the gas strut can support my entire weight (about 70 (+ a bit... you get the idea) kg, without compressing. Huge amount of preload. Then there is the tiny 2mm diameter restriction in the transfer port. 29mm bore, 80mm stroke, hugely oversprung, then strangled down to the UK limit with a stupid little hole. No wonder it's a bit lively to shoot. But the icing on the cake is the pre knackered seal complete with two bits of swarf embedded in it.

http://i1211.photobucket.com/albums/...l/IMAG0581.jpg

http://i1211.photobucket.com/albums/...l/IMAG0582.jpg

These have already visibly scored the cylinder after 500 shots. Another couple of tins combined with the lack of lubrication and the internals would be scrap
It's just as well I got this cheap. If I'd bought this new I'd be somewhat irate.
So, words have been exchanged with BigToe of this 'ere parish, and a plan has been hatched.

1) Ditch the gas strut and go back to a nice spring and guide set up.
2) Two birds with one stone. Sleeve the cylinder down to a 12 ftlb friendly 25mm and hence get rid of the gouges.
3) New piston using the trigger end of the old one brazed to a new front end to match the sleeve. This will incorporate an 'O' ring seal, nylon bearings and shorten the stroke to around 70mm.
4) Take the transfer port out to 3.0mm to give a compression of around 300:1.

Hopefully this will turn what is an attractive, nice handling little rifle into something with the performance it deserves.

[Gwylan]

Should have gone to Specsavers!

Gus

[bigtoe01]

It will be an interesting project for sure, its about time one of us moved onto something not German to tinker with

I personally feel this will turn into an awesome project...really looking forward to seeing how things develop.

[Hangtight]

Anyone want to buy a nearly new BSA/ Gamo gas ram?

[POK!]

The next thing you notice is the fact that the gas strut can support my entire weight (about 70 (+ a bit... you get the idea) kg, without compressing. Huge amount of preload. Then there is the tiny 2mm diameter restriction in the transfer port.

Retro fit Theoben struts are the same. The TP must have changed at some point as I measure my old SS @ 3x15mm.

[Rickenbacker]

I bought a sad (but British if that makes any difference) Lightning (tactical) that I was going to have fettled into a super little springer.

Tactical - Yes, because of the straight grip and thumb-up groove But the plastic stock and .177 cal' made it a fierce little beast to shoot.

The nasty (and light) trigger was relatively transformed by taking a turn off the adjustment screw. But the OP seems to be far more serious about it than I ever was!

I've had around half a dozen Lightnings, including this .22 XL >>here<< that was an all round peach (which I think was the one I sold to Gareth, bless him). But this Tactical was the worst I've had by far...

One day, when I was examining the (deeply unimpressive) breech pin (lack of) design - I noticed some wear on one face of the breech block... flipping it over, I then felt slightly cold and dizzy, as I noticed >>daylight down the side of the barrel<< which was sure enough pointing a good few degrees to the right, compared to the rest of the gun Detaching the barrel proved the uneven wear on the RHS of the breech block... at least its much softer than the breech jaws, which seemed straight and unmolested.

So, just recently, I was moaning about it / showing it to - an aquaintance, who promply shot a cloverleaf group of touching pellet holes, off-hand at 15 yards with it ... he then wildly offered to take it of my hands!

Reading this thread makes me a bit less glad it's gone TBH... and I do hope to get another one some day. And hopefully have it totally fettled.

Finally - if you're going to so much trouble over an XL - I'd think about modding it for a breech bolt (apparently the Mercury S had one??). And a pair of shims wouldn't be a bad idea!

Sorry to ramble on

[Hangtight]

Just for giggles and laughs I may put it together with the strut and the new piston etc. If by some miracle its nice to shoot and under 12ftlb then I might leave it like that for a bit. But Bigtoe has pretty much sold me on the idea of converting it back to a springer. I'll just have to see which I prefer.

[bigtoe01]

The reason for the spring conversion is that you are short stroking it, the ram will be preset to give the rated UK power level at full stroke with a 29mm piston...way more air than you will have when you have finished.

Now I know the TP will be a lot less restrictive which will help, but i feel you will not have the ability to tune it as easy as with a spring...plus rams are a bugger to get in and out quickly...a compressor is needed for sure

Give it a go with the ram by all means, i would however not waste time on it much, make up the guides and pick a nice spring.

Im liking the LGV spring a LOT..

specs are 236mm long, 3.35mm wire, 20.8mm OD, 14.4mm ID, 3.96mm between coils, 33 coils.

I can't find a Titan or after market spring that comes close on specs so may have a batch made up, in a fully sorted 25mm piston gun such as an 80 in .177 with 75 to 79mm stroke this spring is slightly to long (1 to 2 coils), T 20 had to lose 2 coils at 70mm stroke in his 35 project in .177, so the spring is easy up to the job. The shot cycle with this spring is superb, very soft, dull thud and next to no surge when you have the preload right...

[Hangtight]

If you're thinking of having some made up then put me on the list! Looks like if I use the retaining pin for the ram, with the longer nose on the piston then I'll have about 200mm installed length.

[bigtoe01]

If you're thinking of having some made up then put me on the list! Looks like if I use the retaining pin for the ram, with the longer nose on the piston then I'll have about 200mm installed length.

here is a Titan mainspring list:

[CODE]Titan Main Spring size chart split to batch up the springs so you can compare spring specs.

Model # OD ID Wire Coils Length

TS001 21 14.5 3.25 31 280
TS003 20.8 14.73 3.26 34 304
TS009 21 14.75 3.3 27 280
TS010 21 14.8 3.1 27 230


TS005 19 13.19 3 32 290
TS006 19 13.3 2.92 39 341
TS007 20 13.8 3.3 30 255
TS008 20 13.8 3.3 34 295
TS011 18.8 12.8 3 31 230


TS002 22.7 15.5 3.65 30 291
TS004 22.62 15.64 3.65 28 252[/CODE]

If I was to use a Titan I would be looking at the No10 first, then possibly the no 1 (which would need a coil off or 2)

Im debating the springs, im 200quid into springs already so anything I do this next time has to be dead right

[POK!]

specs are 236mm long, 3.35mm wire, 20.8mm OD, 14.4mm ID, 3.96mm between coils, 33 coils.

I can't find a Titan or after market spring that comes close on specs so may have a batch made up, in a fully sorted 25mm piston gun such as an 80 in .177 with 75 to 79mm stroke this spring is slightly to long (1 to 2 coils), T 20 had to lose 2 coils at 70mm stroke in his 35 project in .177, so the spring is easy up to the job. The shot cycle with this spring is superb, very soft, dull thud and next to no surge when you have the preload right...

I have BSA springs made to a similar spec @ 13.9, 3.2, 30x220mm, I'll be having some made in the next month or so.