Self firing Superstar

[Benelli B76]

Got a dangerous BSA Superstar that decides to let go now and then. Stripped the trigger unit down and from observation the step machined in the piston to take the sear contact is very shallow. There seems to be no adjustment on the trigger for let-off only a tiny allen screw that looks like it adjusts travel. Has anyone adjusted the angle of the face on the piston contact surface to produce a heavier trigger ?

Baz

[ggggr]

Got a dangerous BSA Superstar that decides to let go now and then. Stripped the trigger unit down and from observation the step machined in the piston to take the sear contact is very shallow. There seems to be no adjustment on the trigger for let-off only a tiny allen screw that looks like it adjusts travel. Has anyone adjusted the angle of the face on the piston contact surface to produce a heavier trigger ?

Baz

Did you check it before you bought it? I'd be looking for a refund before trying to sort it.
Regarding sorting it--I'm guessing it is a bit like a more complicated Meteor set up like the Supersport is?
I'd be trying it without a mainspring-----just the piston, cylinder and trigger set up and try to see what is going wrong. Try adjusting the allen screw both ways----------usually on Meteors there is not actually that much movement that does a lot but you can wind it in so the thing wont cock and hold or the other way so it wont cock at all.
If you cannot get it to cock and hold with adjustment then I'd look at the sear and see if you can get one to try (Will a Meteor one fit?).

I have heard of Meteor pistons wearing through where the sear catches and people seem to reckon the pistons are still ok to use?

BUT---if you have bought it like that I'd ask for a full refund or a partial one if you intend to keep the gun and have a go. I wouldn't sell on a gun in that condition unless the buyer was fully aware of it's conditon.
Good luck with it.

[Benelli B76]

Guy, its not mine, I tend not to buy regular rifles anymore, has to be a bit different like the Titan .25 which I purchased this week. The triggers on these Superstars are fiddly and complicated. I have another in parts for spares, tried fitting the sear from that and even worse result, it does not catch. Next test is to change pistons around, as I said the latching shoulder is very shallow and even looks dangerous !

Baz

[ggggr]

Guy, its not mine, I tend not to buy regular rifles anymore, has to be a bit different like the Titan .25 which I purchased this week. The triggers on these Superstars are fiddly and complicated. I have another in parts for spares, tried fitting the sear from that and even worse result, it does not catch. Next test is to change pistons around, as I said the latching shoulder is very shallow and even looks dangerous !

Baz

Just try the piston and the sear without the rest of the trigger Baz to try to isolate it. If it wont latch with either sear, then repeat with both pistons. If it still doesn't latch then I guess it is a case of trying to square up the bearing face of either the sear or the piston---But I'd be wary of any going through any hardening. Have you tried a sear off a Meteor by any chance?

[Benelli B76]

The Meteor sear does not have the little cross pin the superstar needs. Think I will try the other piston first, pity I can't phone the clever guy who designed it, Roger Wackrow.

Baz

[ggggr]

The Meteor sear does not have the little cross pin the superstar needs. Think I will try the other piston first, pity I can't phone the clever guy who designed it, Roger Wackrow.

Baz

Off the top of my head--are 3 of the holes in the trigger housing the same as for a Metoer? Ie of your piston swap doesn't work, can you try a mk3,4 or 5 Meteor set up in it???

Part of the reason I like simple things--the less in it the less to go wrong.

[Benelli B76]

Off the top of my head--are 3 of the holes in the trigger housing the same as for a Metoer? Ie of your piston swap doesn't work, can you try a mk3,4 or 5 Meteor set up in it???

Part of the reason I like simple things--the less in it the less to go wrong.

The Superstar trigger side plates have a lot more holes but there may be three in the correct positions to try the Meteor setup, its a thought.

Baz

[SRV1]

A Superstar I bought at a local auction was also dangerous....Someone previous had a dabble in the trigger mechanism and fitted the trigger spring incorrectly, they must have had a crowbar in there as the spring was bent way out of shape. A new spring from Chambers sorted it.

[nige346]

You may have fixed this by now, however one area of the Superstar, lightnings ect that can wear is the pin hole in the trigger plate, this can wear to become oversize so when you cock the rifle the pin moves subsequently allowing the trigger to fire, I have fixed a few by machining a longer pin and making small plates with slightly undersize holes and tig welding onto the trigger frame, you will need to fit a pin (I normally used a brass dummy pin) prior to welding and ensure all is square before doing so, once welded run a correct size reamer through to size properly and ensure all is squared, The new plates can be thicker than the original trigger frame and give a greater surface area, Those that I have done have never failed since, More a fiddly job than complicated, may be worth checking for any wear in the frame pin holes.

[Benelli B76]

Thanks for the info Nige, I did eventually fix it to work well by swapping some parts around. Then blow me down I got a Goldstar with the same problem and these tiggers are similar but have even more parts to them. With this one someone had stripped it and put back the trigger spring (CS163) in the wrong way round.

Baz