Some info required about BSA Mercury please

[charliemow13]

So today I picked up a rifle from my dad. It's basically a barn find, it was left in a property my brother bought, he doesn't want it as he's into powder burners and my dad has no use for it so it's cone to me. And I like to tinker.

A few questions have come up as I've been looking it over and I wonder if anyone could help please.

The muzzle has what I'd usually describe as a counterbore, a larger diameter bored down with a flat bottom before you get to the crown proper. Is that usual on ZA mark1 mercury's?

The trigger has two adjustment screws in the front face of the trigger guard. One for travel and one for spring tension / pull weight. I thought the mercury didn't have that so has someone put on a trigger unit off a different model?

The spring is square coil, again I'm not sure if that was standard or if it's an aftermarket addition?

I put five pellets through it just to see that it was legal and with superfields it did from 521 - 531. So low on oomph. The piston doesn't move freely at all, and it all looks very grungy. When I get chance to find my punches and knock the pin out for the cocking linkage and pull the piston out I'm fairly sure it's going to look pretty messy!

Hope the pictures help and sorry for such a long rambling post! Thanks all.
http://imgur.com/a/mOHkmei

[T 20]

So today I picked up a rifle from my dad. It's basically a barn find, it was left in a property my brother bought, he doesn't want it as he's into powder burners and my dad has no use for it so it's cone to me. And I like to tinker.

A few questions have come up as I've been looking it over and I wonder if anyone could help please.

The muzzle has what I'd usually describe as a counterbore, a larger diameter bored down with a flat bottom before you get to the crown proper. Is that usual on ZA mark1 mercury's?

Perfectly normal

The trigger has two adjustment screws in the front face of the trigger guard. One for travel and one for spring tension / pull weight. I thought the mercury didn't have that so has someone put on a trigger unit off a different model?

That's all correct

The spring is square coil, again I'm not sure if that was standard or if it's an aftermarket addition?

That's an aftermarket Ox or Airforce spring

I put five pellets through it just to see that it was legal and with superfields it did from 521 - 531. So low on oomph. The piston doesn't move freely at all, and it all looks very grungy. When I get chance to find my punches and knock the pin out for the cocking linkage and pull the piston out I'm fairly sure it's going to look pretty messy!

I'd leave the pin in the cocking arm alone and just remove the barrel hinge pin instead --- it's easier that way

Hope the pictures help and sorry for such a long rambling post! Thanks all.
http://imgur.com/a/mOHkmei

Hope this helps




All the best Mick

[charliemow13]

Cheers Mick. Nice to know it's pretty much standard apart from the spring. And thanks for the tip about the hinge pin.

[T 20]

You may as well take the barrel hinge pin out to disassemble as this will also release the barrel detent for cleaning and oiling.



All the best Mick

[charliemow13]

I'll be sure to look out for springs flying out to the darkest corner of the garage when the pin gets tapped out. Going out to perform a pistonectomy shortly. Amusing picture of grease caked crusty piston with embrittled buffer and worn out o-ring to follow!

[steptoe1966]

Hi is ZA not an early MK2 not a MK1 . well on the listing I got it is Z is a MK1
Z MK1 71-73
ZA MK2 73-74
ZB Mk2 74-78
ZC MK3 78-85
ZD Merc challenger 85-86
ZH Merc S 80-85

[T 20]

I'll be sure to look out for springs flying out to the darkest corner of the garage when the pin gets tapped out. Going out to perform a pistonectomy shortly. Amusing picture of grease caked crusty piston with embrittled buffer and worn out o-ring to follow!

Hi Charlie

You may find you've got the weird early nylon piston head with a steel circlip around it, if so I'd change to the later aluminium piston head.



All the best Mick

[T 20]

Hi is ZA not an early MK2 not a MK1 . well on the listing I got it is Z is a MK1
Z MK1 71-73
ZA MK2 73-74
ZB Mk2 74-78
ZC MK3 78-85
ZD Merc challenger 85-86
ZH Merc S 80-85

Ah, I'm by no means the world's top expert on these, but I tend to go off Chamber's parts diagrams when I can, which from the pictures given show Charlie's gun to be a later MK 1. :-

MK 1

image.jpg




MK 2

image.jpg



All the best Mick

[charliemow13]

I was going off the diagram on Chambers as well. And after a bit of heat from my industrial hair dryer and some gentle persuasion the pistonectomy was successfully completed. You were spot on Mick, weird plastic piston head with steel circlip. My next question was going to be re-use or replace, but you already given me an answer to that one 😁

Don't check out the linked pics if utter filth offend you!

http://imgur.com/a/k1dLJMK
http://imgur.com/a/IAyyzRR

[johnbaz]

I got this out of a Mk6 Airsporter action!, No trigger block though!! Had to drill two holes to unscrew the bush!!, It was very clean when it came out too and not swollen, Wasn't stuck a bit!




Only trouble was that I promised the piston to a lad of facebook that needed one and I can't remember where the hell I put it!

Would I be correct in assuming that the piston is transferrable between the Merc's and 'Sporters?



John

[T 20]

Would I be correct in assuming that the piston is transferrable between the Merc's and 'Sporters?

John

Hi John

Airsporter MK4 to MK7 and Airsporter S pistons are the same as Mercury MK1 to MK4 and Mercury S Pistons.




All the best Mick

[johnbaz]

Hi John

Airsporter MK4 to MK7 and Airsporter S pistons are the same as Mercury MK1 to MK4 and Mercury S Pistons.




All the best Mick

Ahh, Cheers Mick, I didn't think to exclude the early pointy ones!!

I have a Mercury Challenger that was serviced just before I bought it so i've not had to open it up, I wonder it that's same?


John

[T 20]

Ahh, Cheers Mick, I didn't think to exclude the early pointy ones!!

I have a Mercury Challenger that was serviced just before I bought it so i've not had to open it up, I wonder it that's same?


John

No, John.

The Mercury Challenger has a different piston in order to clear the lugs on the Maxgrip Scope Rail.




All the best Mick