BSA Lightning trigger adjustment improvement

[Neil54]

After polishing the sears on my trigger the second stage still felt heavy, smooth but heavy.
This got me to thinking.
Now the Lightning trigger is to all intents and purposes a copy of the Gamo trigger. This trigger appears in many disguises and from a multitude of manufacturers.
It was used on the Rapid mk1 for example.

The only adjustment on the trigger is for sear engagement. Screw it in too far and the gun won't cock, too far out and the second stage is very long.

Now my first thought was to replace the adjustment screw with one on the trigger instead.


Marked in red, this screw would give a greater mechanical advantage and thus a lighter trigger pull. You would however loose the two stage.



Adding a second screw , marked in blue, would restore the two stage. The blue screw would adjust sear engagement, the red screw second stage travel.

Now to fit the screws the holes in the trigger which the existing screw passes through would need to be filled in, then drilled and tapped to accept the new adjustment screws.

If I can find a bit of aluminium I may make another trigger to prove this.



Please note all images (however poor) are mine and should nor be distributed without my consent.

[Shed tuner]

or use the existing hump as the second stage, and just add the first stage screw as you suggest...

I did much the same on a FWB sport trigger years ago. I also did it to a couple of jaguar crossbows, as seen here from about 4 minutes in https://www.youtube.com/watch?v=RXBPMQREYPQ

The basic concept of having two contact points for each of the stages on a trigger blade is a pretty tried and tested formula - just do it

NB your red line will have less mech advantage than your blue... whilst red is further from the intermediate sear pivot, it's even further (proportionately) from your trigger pivot point. so say from a trigger leverage perspective it's + 25% effort (ratio of red line from pivot to existing hump from pivot), and from an intermediate sear perspective it's -15%, so net +10% (OK it's not literally as I simplified the maths, but you get me)

[maximus]

Hi Neil, you inspired me to have a go at making a custom trigger so today I spent a few hours filing one up out of ally. Nearly at the point where I can try in the gun. It definitely gives a true two stage trigger at least. The weight of the first stage seems quite heavy and is a function of the spring between the two sears so not adjustable unless the spring is tweaked. Like yours the finish on my sears was as rough as but I have given them a good polishing with emery and wet and dry. Might get a chance to try tomorrow. Cheers Max

[Neil54]

I made a trigger out of plastic.

Out of the stock it was definitely two stage.
Once in the stock the two stages are less defined.
The trigger is a lot lighter as I have moved the pivot point 5mm rearward.
I have some aluminium on the way.

[maximus]

I made a trigger out of plastic.

Out of the stock it was definitely two stage.
Once in the stock the two stages are less defined.
The trigger is a lot lighter as I have moved the pivot point 5mm rearward.
I have some aluminium on the way.

Do you mean that you drilled another hole in the trigger cage 5mm to the rear of the gun?

[cptman]

Luckily this gun is quite short so it fits in the bin more easily.

[junglie]

Luckily this gun is quite short so it fits in the bin more easily.

Lol obviously we share the same unlove for lightnings.

[Neil54]

Do you mean that you drilled another hole in the trigger cage 5mm to the rear of the gun?

Yes, I drilled a new hole for the trigger pivot.
It ended up lower than the original and about 5mm rearward.

[maximus]

https://imgur.com/gallery/h3jHGo5

This is mine in the rough. Now profiled and polished but using original pivot. I have got a true two stage feel but it is quite heavy and I do get trigger hang. Won't be able to touch it next week but interested to see how you get on. Regards Max

[maximus]

Luckily this gun is quite short so it fits in the bin more easily.

Oy!!! Not quite at that stage with it yet

Whilst accuracy testing I swapped scopes with my 95 to see if my bargain BSA 3-9x40 was hindering my efforts. It wasn't. A few shots with my fettled short stroke 95 hi-lighted the difference between the two guns. The 29mm diameter cylinder BSA will never be able to beat the 26mm HW, the pseudo two stage trigger of the BSA will never beat the Record on the HW. However, the BSA is better looking and has walnut rather than Beach so better VFM in that respect than the HW.

[TonyL]

Not joining in to knock the BSA, but it's sounding a little like we've got used to over the years. Many of their lighter break barrels handle really well and can be very pleasing to the eye, especially in nice walnut frocks. But they'll not deliver that precision and finesse offered by the HWs, with their Rekord triggers, finer engineering and solid build. Especially 25 and 26mm ones (although some 30mm ones can boast lovely manners properly set-up). Horses for courses......

[maximus]

I'm not sure what it is about the lightning CLX which makes it require the heavy piston to make power. If I compare the vital statistics to my modern HW 35, 30mm bore and I think 65mm stroke, lightning 29mm bore and 70mm stroke. T.Ps both around 3mm though the 35s will be longer. I am wondering if it's just the piston seal efficiency that's maybe holding the lightning back? It was quite a tight fit so I sized it down a bit but still snug. Maybe Evert has experience of tuning these guns and can advise any tricks to unleashing their power potential?

[evert]

Maybe Evert has experience of tuning these guns and can advise any tricks to unleashing their power potential?

I've settled for 11-12fpe in the "old" lightnings and supersports, depending on calibre and gun, throwing out the heavy long "nail" piston
weight that came with the full power guns we got here in Norway.

My guns are now all set up using the Titan #1 spring (uncut), a well fitting piston seal, a delrin tophat and tight delrin rear guide,
and the the two original steel washers in front of the piston sleeve.
All with the original tight transfer port, and there probably is some bounce, but I like the shotcycle and the guns are accurate.

[TonyL]

I don't know by how much the later rifles differ from the earlier ones, but my early Supersport seems very efficient. Standard TP (I believe), no piston weights and the standard spring had to be cut down a few times to get it below 12. After cropping the spring, it makes high-11s very easily, is very easy to cock and has excellent firing manners.

[junglie]

I don't know by how much the later rifles differ from the earlier ones, but my early Supersport seems very efficient. Standard TP (I believe), no piston weights and the standard spring had to be cut down a few times to get it below 12. After cropping the spring, it makes high-11s very easily, is very easy to cock and has excellent firing manners.

The tatty old supersport I picked up for £60 shot really well too, had a decent trigger too funnily. It had 2 quid coins in as piston weights putting it a tad warm so was only £58 really once I'd removed them, degreased them & spent them.....lol. Should have kept that instead of selling it & trying lightnings .