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Double Rifles, Single Shots & Combinations >> Double Rifles
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bluedevil
.224 member


Reged: 02/12/04
Posts: 40
firing pin shapes and problems
      #29241 - 10/04/05 04:49 AM

Hi Guys,
My Jeffery boxlock was made in 1912 and though in excellent shape, has seen at least a fair amount of use -- i.e. right bore worn more than the left with a velocity difference between the two. Both firing pin heads are shaped like a half moon and leave a half moon shape in the primers of fired cases. This has never affected ingition, but should I have them rounded off? If so, by whom? I have occasionally, when working up loads, experienced a little stickiness on trying to open the action, with loads that do not seem to be excessive (it is a .333 Nitro rimmed and there is very little, in fact no reloading data that I can find). Can difficulty in opening be caused by the pins sticking, or is it always the case that the metal has expanded from the pressure? Is this a common occurence with older doubles? Any info would be greatly appreciated. Thanks, Keith

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mickey
.416 member


Reged: 05/01/03
Posts: 4647
Loc: Pend Oreille Valley, Idaho
Re: firing pin shapes and problems [Re: bluedevil]
      #29262 - 10/04/05 12:53 PM

I have no idea where you are at but a qualified smith can round the edges or replace if need be. After 75 or so years springs also where out.

I know my springs are wearing down.

--------------------
Lovu Zdar
Mick

A Man of Pleasure, Enterprise, Wit and Spirit Rare Books, Big Game Hunting, English Rifles, Fishing, Explosives, Chauvinism, Insensitivity, Public Drunkenness and Sloth, Champion of Lost and Unpopular Causes.

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ArnoldB
.300 member


Reged: 23/07/04
Posts: 139
Loc: Uk
Re: firing pin shapes and problems [Re: bluedevil]
      #29266 - 10/04/05 01:41 PM

I would leave them as is but check that the cocking of the hammers is done as soon as you open the gun. A gun of that age can have worn cocking limbs and be difficult to open to the point where you won't be able to open it all. The strickers will stick in the cartridge.
It also depends on how much the strickers protrude from the action and depth of rim..
Let a recognised double gunsmith check it over.

Arnold

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JPK
.375 member


Reged: 31/08/04
Posts: 734
Loc: Chevy Chase, MD
Re: firing pin shapes and problems [Re: bluedevil]
      #29268 - 10/04/05 01:59 PM

Not quit a direct comparison but I had a double shotgun quickly looked over by Paul Chapman of G & H and he asked if I ever had misfires. I hadn't and told him so. He responded by telling me that if I started too that it would likely be due to the pins being peened from use. This gun is my travel gun, was made for me, and is an Arrietta 12ga. with maybe 50,00 rounds fired through it. I had the pins replaced and kept the originals as spares just to head off any problems. Pretty inexpensive insurance if your going to do any traveling with the gun.

My thoughts,

JPK

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Marrakai
.416 member


Reged: 09/01/03
Posts: 3490
Loc: Darwin, Top End of Australia
Re: firing pin shapes and problems [Re: JPK]
      #29271 - 10/04/05 02:28 PM

bluedevil:
If the firing-pins are sticking in the primers, you should be able to see an obvious drag-mark in the lower part of the firing-pin indentation. If the indentations are clean, there may be other problems.

If your loads are hot enough to cause sticky extraction in a double, you are WAY overloaded and at immediate risk of damaging the gun, and perhaps yourself. I sure hope this is not the case! If you are using medium-slow to slow powders, and not exceeding published velocity for that bullet-weight, you should be in a safe pressure range. According to the 1926 ICI and 1925 Nobel's catalogues, the .333 Flanged factory-loads turned up 2150 fps for the 300-grainer and 2400 fps for the 250-grain bullet. Are you using a chronograph? Its by far the most important tool of the Brit double-rifle reloader.

BTW, found a couple of loads for the .333 Flanged buried in Wal Winfer's British Single Shot Rifles Vol.3, with the usual warnings, as follows:

275gr bullet, 50gr 4350, 2,200 fps.
300gr bullet, 52gr 4350, 2,200 fps.

Not the 250-grainer I know, but it all helps.

--------------------
Marrakai
When the bull drops, the bullshit stops!
--------------------------------
www.marrakai-adventure.com.au

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NE450No2
.375 member


Reged: 10/01/03
Posts: 942
Re: firing pin shapes and problems [Re: Marrakai]
      #29272 - 10/04/05 03:06 PM

Bluedevil,
Yes the size and shape of the firing pin and modern primers can cause some "stickiness" when opening the rifle with loads that are within pressure.
Original ammo had larger Berdan primers.
On some rifles the primers are removed from the front of the action, usually a bushing with 2 holes for a bushing wrench, I have seen even these holes cause problems if they are very close to the firing pins, thus allowing the primer to extrude into them.
Only allow a person with double rifle experience to work on your rifle. I can recommend JJ Perodeau at www.champlinarms.com

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bluedevil
.224 member


Reged: 02/12/04
Posts: 40
Re: firing pin shapes and problems [Re: bluedevil]
      #29290 - 11/04/05 03:30 AM

Dear Maraki and others, Thanks for the info. I do use a chronograph and only slow burning powders, including R22 and IMR 4831. I have not exceeded 2,300 feet per second and my best load produces about 2,250 in the left barrel and a little less than 2,200 in the right barrel, well under the 2,400 advertised. So I don't think pressure is the problem. I will check for drag marks. Thanks again, Keith

PS Is it common for doubles to be proof marked for one load and regulated for another? My Jeffery is proof-marked 42 grains Cordite 300 Max, but the barrels are inscribed "for 250 grain bullets."

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NE450No2
.375 member


Reged: 10/01/03
Posts: 942
Re: firing pin shapes and problems [Re: bluedevil]
      #29308 - 11/04/05 01:21 PM

bluedevil,
It is not uncommon for a double rifle to be proofed for one load and regulated with another. I have seen a couple of other 333 Jefferys the same as yours.

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