Modding BSA Lightning XL trigger

[POK!]

It's sear overlap that's responsible for the long trigger pull in both Gamo and original Supersport triggers. If it's very long as in all Gamo and some BSA it can't be polished out IME, you have to grind the sear to reduce engagement. If your BSA has a little creep polishing can help. A wonky chassis and overtightening the rear stock screw can also introduce some creep on older BSA's. Installing a CDT blade on a new Lightning will give you a true 2stage fully adjustable trigger that will probably be better than the very best old style BSA.

[Hangtight]

As POK mentioned, the sear overlap is quite large so there is quite a lot of slightly rough metal to drag over more slightly rough metal under enormous pressure, with a slightly shonky piece of plastic before anything happens. I did try adjusting the trigger 'weight', but all the adjustment screw does is move the primary sear closer to the point of disengagement, so by the time you're getting close to a nice clean break the trigger is becoming unsafe. I did try one that had been polished but it still felt vague, just somewhat less agricultural.
The positioning and action of the safety was something else I grew to dislike with use so the chance to kill two birds......that and I can't help fiddling!

[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.

[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.