doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Light primer strikes

Some months ago i asked for advice on light primer strikes on that I am experiencing with my 1950 Boswell box lock hammerless double gun. I received several helpful responses which I am grateful for.

New hammer springs were fitted by a local gunsmith that unfortunately didn't solve the problem. A local gun dealer imported a pair of heavier V spring from Italy recently which were fitted to the gun today. My gunsmith has just contacted and both firing pins are still striking the primers lightly.

The issue he has noticed is when the trigger is pulled and the hammer is released (the hammer and firing pin are not separate, the tip of the hammer is the firing pin), the noise is quite soft and sounds weak. In other words, it sounds lazy and not energetic like a normal gun when the trigger is pulled. The gunsmith said this is abnormal and he is at a loss on how to repair this otherwise nice gun that under normal circumstances should be repairable.

The gun doesn't appear to have been worked on over the years and is in excellent condition for its age.

Again, any further thoughts would be greatly appreciated.

Try Cheddite primers.

I know it's not a 'fix', but they are the most sensitive of the bunch.

I certainly wouldn't propose to think I know more than your gunsmith, but having had similar problems over the years I can suggest that there are numerous things that can/will cause this.

I would think that your gunsmith would have thoroughly cleaned the action innards of any stiff gunk that may have accumulated over time. If not, a hot bath in an ultrasonic cleaner with a bit of Dawn dish soap, then a thorough drying and proper lubrication can work wonders. Then, check for free, unhindered movement of the hammers.

Another consideration is that of the chamber rim cuts. I have some vintage guns that have deeper rim cuts than others and it allows certain brands of shells to sit a bit too deeply in the chambers and the strikers just can't get to them as well, resulting in light strikes.

In that vein, have you tried various shell brands to see if your problem is limited to one or two brands, or if it occurs with all brands? I have found that B & P Comp One loads have a different shell head rim thickness, or shape, that allows them to sit deeper in the chambers. I only have a couple guns that will fire them 100% of the time.

One other possible culprit is that the gun may not have sufficient firing pin protrusion through the standing breech. If you have the means to do so, hold the hammers at maximum contact with the back of the standing breech, where they fall, and measure the amount of protrusion through the breech.

Again, all these things should have been checked by a competent break-action 'smith, but it's where I'd start anyway. Good luck.

Check the axle the tumblers rotate on for wear, or, a bend. Check for interference between the tumblers and the frame, due to wear or misalignment. Make sure the surfaces of the sear and the area that it contacts on the tumbler, after being released from the bent, is not rough or worn.

Best,
Ted

All good advise above. Perhaps try the gun assembled with the stock off and you might see what's happening. I would coat the hammers with a black sharpie and see if they rub inside the frame.

I would also have the original springs put back in the gun since the over powered springs did not solve the problem. The heavy springs may set off a chain of events that will cause additional problems. Primarily excess wear to the bent and sear nose.

I'm not a gunsmith but I've been keeping my old doubles going for a long time. I bet you'll find the answer and it will be something simple. Please let us know since someone else may have the same problem.

+1 on returning to the old springs. No need for new problems.

I have a similar problem on an 1885 Winchester target rifle that is equally vexing. It has a titanium, short-fall hammer that uses both coil and flat springs. After years of flawless service, it is suddenly giving me sporadic light strikes. Cleaning did not help. Protrusion is fine. But something is amiss.

For all ammo or just a specific brand?

So your problem "mainly" started with reloaded shells. You may have identified your real problem before this long effort to fix your gun. Be aware you can over seat a primer when you seat them. Look at the hulls that fail to fire. Is the primer seated properly or has it been over seated. With my Spolar I had the hydraulic cylinder adjusted so the shaft traveled too far by about 1/4" which caused me to over-seat the primer if I stayed at the bottom of the cycle too long. Pressure, over time forced the primer too far into the primer pocket. Go fast and it never did it, but if I stayed at the bottom of the cycle, several extra seconds, it would. This was on brass headed shells and never the steel headed shells. I had adjusted my cylinder longer to better seat primers in those steel hulls and it caused a problem in the brass headed hulls later. I no longer load any steel headed hulls like Remington game or promo hulls. You can even see the base of the shell is dipped in slightly.

I also had this happen with a MEC hydraulic loader once when I had a buildup of crud in the primer seating station. The newer, multiple part MEC primer post system works fine unless it gets crud in it. Some primers are flatter than others and can naturally over seat in certain hulls. If your problem was mostly with reloaded shells make sure they are not the real problem.

Home-brew, black-powder ammo in .45-70 starling cases with CCI-BR2s. I've been using that brass and primer for about 15 yrs now. Hundreds of shots per year. Why now?

Jack Rowe,the late Birmingham, England gunmaker was fond of stating that there are gunmakers and there are "gunsmiths"--he considered himself a gunmaker and rightly so.

Let me tell you about a 50 year old Piotti 12 bore boxlock ejector (BLE) that came into my shop which is owned by one of the members of this forum. Said Piotti BLE was made in the 1960's sometime and was purchased via a USA auction earlier this year. Straight away the new owner experienced misfires (light strikes of the tumbler) of the left barrel. I disassembled the action completely and checked for the tumbler fall by gravity to determine if there was anything preventing the tumbler from falling on its own. There was none. The left hand tumbler mainspring was a bit undersized but that was not the real issue. After viewing and studying the gun and taking measurements I discovered that when the action of the gun was originally machined in the Piotti factory in Italy that the action maker did not machine the slot for the left hand mainspring deep enough in the action and therefore when the gun's tumbler was installed with the mainspring the mainspring was "cramped". The solution was to machine the slot for the left hand mainspring .050" deeper (as it should have been done) make a new V mainspring and the problem with light striking of the left barrel was eliminated. Can you imagine all the frustrations of the 50 years of owners of this Piotti.

You need to take your gun to a gunmaker.

Kind Regards;
Stephen Howell