BSA Mercury Mk2 power question.

[Punchsteve]

Could any of you knowledgeable types please tell me what power these were supposed to put out?

Not how much power you can get out of them with fettling, just the average power when they came out of the factory please.

I've a Mercury MK2, putting out about 8.5ftlb on average and I'm trying to decide whether to take it apart and have a fiddle or not.

Any info would be much appreciated.

Thanks,
Steve.

[madcarlos]

was told about 10 ,

[torrens]

I'm no expert but the last one I had was easily equal to a good early Airsporter, I'd think 10ft lb would be about right in standard fettle. Might be worth an overhaul.

Torrens

[Punchsteve]

Thanks lads, much appreciated. I'll have a tinker with it then.

[madcarlos]

hi i sold mine a while ago and replaced the rubber o-ring seal give a good clean inside added a bit of lube and dropped a titan xs mainspring in , which did increase the power quite a bit ,,,,,,,

[Punchsteve]

hi i sold mine a while ago and replaced the rubber o-ring seal give a good clean inside added a bit of lube and dropped a titan xs mainspring in , which did increase the power quite a bit ,,,,,,,

Thanks for that mate. I have got a few bits ready for it but wasn't about to waste them if the end result would be the same as I'd already got.

It's the titan spring I've got for it as well, and by the looks of it, it'll need cutting down and chrono'd to try and get it at that balance between power and 'smoothness'.

Having taken it apart, I'd say that no one has touched it for quite a few years. The piston buffer seal crumbled (as usual) though the plastic piston head is in very good nick. Not sure whether to keep it and save the new alloy one for a rainy day to be honest.

It hasn't been 'roughed', I'd say, just not used for quite a few years.

[mrto]

Could any of you knowledgeable types please tell me what power these were supposed to put out?

Not how much power you can get out of them with fettling, just the average power when they came out of the factory please.

I've a Mercury MK2, putting out about 8.5ftlb on average and I'm trying to decide whether to take it apart and have a fiddle or not.

Any info would be much appreciated.

Thanks,
Steve.

Hi,
I have a MK2 that after a new spring and buffer washer, O ring etc is doing 11 plus ftlbs.ATB.

[maximus]

I'm no expert but the last one I had was easily equal to a good early Airsporter, I'd think 10ft lb would be about right in standard fettle. Might be worth an overhaul.

Torrens

You should get more out of a Mercury than an Airsporter due to it being a more effcient design. I reckon std they were about 9.5-10 ftlbs. I have a freind who has put a Bonnie and Clyde kit in his and it is doing 11.5 no problem.

[Bolor]

The mercury and airsporters were easily capable of power just under the legal limit. Remember a thirty plus years gun is going to be lacking in power. Start by a good service and replace any seals and springs. That is all you should need for a near full power gun. I would try and source the original spring for the gun if I were you. In export guise these guns kicked out 16ftlb and were detuned for uk Market.

[pennineway.fswo]

Could any of you knowledgeable types please tell me what power these were supposed to put out?

Not how much power you can get out of them with fettling, just the average power when they came out of the factory please.

I've a Mercury MK2, putting out about 8.5ftlb on average and I'm trying to decide whether to take it apart and have a fiddle or not.

Any info would be much appreciated.

Thanks,
Steve.

Hi Steve

Calibre makes a difference of up to 1.5 ft lbs

So if yours is a .177, then don't expect more than 9.5 ft lbs with manufacturers spring etc.
A good .22 will give around 11 ft lbs with the right pellet

Mercurys almost always outperform Airsporters in the power game due to the more efficient feed of pellet into the breech and less lost volume from the loading tap. Make sure the breech seal is healthy though.
ATB
John

[coddy]

fit a hw breach seal mate .coddy

[MattyBoy]

fit a hw breach seal mate .coddy

HW 30 I believe to be specific

That's what the Meteor uses and it should be the same barrel spec...

Can anyone confirm this 100%?

Cheers

[Punchsteve]

Thanks for all the info lads.

I did a bit of work on it today, following the tuning guide (posted by Alistair IIRC).

Degreased the internals and the piston (the grease in it had near on turned to a powder), sanded out the scratches on the piston, ready to be polished, and am now waiting on some dri-slide stuff to coat the insides before I can continue.

Got a new spring, piston head, buffer washer, piston seal and breech seal for it so hopefully, I can bring it back up to par.

The Mercury, even though it's long been left behind by modern springers, is one of my favourite guns.

[Airsporterman]

The Mercury has a good following like the Airsporter, a healthy version of either rifle should be putting out around 10.5 ft/lbs in standard form, it's not the ultimate power you seek in either, as power does not necessarily mean the best performance, smoothness, consistency and accuracy.
The big mistake people often make is going all out for power, it usually spoils them!

Airsporterman

[hawkeye]

had mine from new and it dropped to around 5.5ft lbs , changed mainspring and piston seal plus relube and it was doing around 9 - 9.5 changed the breech seal and its doing 10.5 - 11 ftlbs should go up after running in , originally it was doing around 11.6.