J. Blanch & Son 12 Bore Damascus: hammer spring replacement required

[fizzbangwhallop]

I've got a nice J.Blanch & Son of 29 Gracechurch Street damascus barrelled hammer 12 bore which has been nitro'd but I've posted this enquiry in here as it used to be black powder and there's probably more chance of someone who knows in this section.

The RH hammer has a tendency to perforate the cap (depending on the make of cartridge) on firing and having looked at it more closely I think this is down to the spring being noticeably stronger than on the left so I'd like to replace it with one to match. The firing pins were replaced a couple of years ago and it hasn't done much work since.

So I'm after someone reasonably local to fit a weaker hammer spring to her or failing that any recommendations as to a source for these springs. I'm quite happy to remove the LH spring in order for it to be matched.

Any advice and suggestions gratefully received.

Best wishes

Fizz

[enfield2band]

The RH hammer has a tendency to perforate the cap (depending on the make of cartridge) on firing.....

Any advice and suggestions gratefully received.

Best wishes

Fizz

Hi,
I think that if hammer is perforating the primer then it will be because the pin is too long. You need to hone it down gradually, or you could try swapping the pin over to the other barrel, and vice versa, and see if it does the same. It is how far the pin travels that is the deciding factor, not the strength of the spring, (unless you get mis-fires).
Primer hardness tends to vary so I would not use that as a guide.

ATB.

[fizzbangwhallop]

Thanks for the reply Enfield, much appreciated.
Having had another look I feel it's possibly a combInation of an over strong spring and a slightly over length pin.

It's not a recent problem and this is it's third set of pins, there is evidence of pitting on the face around the f/pin hole, on the nose of the f/pin and, more significantly, I've noticed the fence is being flattened by the underside of the hammer.

The nipple isn't obviously shorter but I guess it's a combination of several minor things but I would like to start with a lighter spring.

Atb
Fizz

Just had a look at the results from the British Side by Side Championship held at Sporting Targets last weekend and it scored a 72. Pleased with that but it wasn't in my hands.

[enfield2band]

Thanks for the reply Enfield, much appreciated.
Having had another look I feel it's possibly a combInation of an over strong spring and a slightly over length pin.

It's not a recent problem and this is it's third set of pins, there is evidence of pitting on the face around the f/pin hole, on the nose of the f/pin and, more significantly, I've noticed the fence is being flattened by the underside of the hammer.

The nipple isn't obviously shorter but I guess it's a combination of several minor things but I would like to start with a lighter spring.

Atb
Fizz

Just had a look at the results from the British Side by Side Championship held at Sporting Targets last weekend and it scored a 72. Pleased with that but it wasn't in my hands.

Hi Fizz,
There could be more than one problem here?
The pitting, as I am sure you know is caused by the hot gases escaping from the perforated primer.
I am surprised that it has had three pins so far. Is this on the one barrel? If it is then your thoughts on the spring may be right.
But, Could the fault lie with the firing pin or nipple? If the pin is not tempered hard enough it might be getting deformed by the hammer blow which is causing it to protrude too far into the breech. Or, is the nipple too soft and that is deforming and allowing the pin to travel too far?

The fences being damaged by the hammer sounds to me that the inside face of the hammer has worn out. With old blackpowder guns they braze in a small plate or put some weld in. There is a danger that you can ruin the temper of the hammer by doing this but so far I have not heard of any breaking.

I'm clutching at straws here: Is it possible to use a spring balance and and get a reasonably accurate idea of how much force is need to bring the hammer/s to full cock. If you can arrive at an average you are happy with perhaps you could try a hammer gun in a shop and see what pressure they need. It may cast some light on your problem?

Alternatively, on fleabay there are sometimes pairs of sidelocks or pairs of back action locks for sale. The springs might not suit your gun but the supplier might have access to spare parts or be able to advise where you can get new/replacement springs if you need them.
Go to "hunting" "accessories" and select "used" this will narrow down the amount of items you will need to trawl through.

Hope this helps.
Atb.

[RichardH]

Your issue is pin protrusion not spring pressure.

Swap the pins over to confirm this then shorten the bad one in line with the good.

Peterdyson.co.uk is a good source of springs and pins but i suspect a simple shortening will sort things

Rich

[keith66]

Your issue is pin protrusion not spring pressure.

Swap the pins over to confirm this then shorten the bad one in line with the good.

Peterdyson.co.uk is a good source of springs and pins but i suspect a simple shortening will sort things

Rich

J Blanch was a top notch gunmaker, the gun will be how old ? 100years? I cant see for a minute the spring being too strong. Pins have been replaced there lies the problem. Sounds like it needs a decent gunsmith to make sure its replacement firing pins are up to the quality of the rest of it.