Issues with .50-70 loads and smokeless powder

[David LaPell]

I have a Chiappa Sharps carbine in .50-70 Government. My loads are 450 grain cast bullets, 12.0 grains of Unique. I've shot the gun before, never had any issues so far but today I was having problems that eventually led to a squib load.

I took the gun out, shot it at 50 yards and 125 yards. I got a couple of what I thought were light primer strikes. Each time, I took the round out, examined it, and wasn't sure why I got them, never had them before with this gun. On some rounds, they fired just fine. Finally, had one round that seemed like a light strike, BUT, turned out that the bullet came out and got stuck just into the breech. I've had Sharps rifles before so I know not to open the breech without the gun being in half-cock, but this gun has less than 100 rounds through it, shouldn't be giving me trouble, so I'm wondering about the loads. I know, except for the last round that led to a squib, each round went off after the second try (again, I checked each round before trying to fire again).

https://i.imgur.com/rctDViq.jpg?1

The target today at 50 yards.

https://i.imgur.com/6ElA0ha.jpg?1

The .50-70 Government round with the 450 grain bullet, 12.0 grains Unique.

https://i.imgur.com/fZmSVpN.jpg?1

A fired case on the left, the case with the light strike (unfired) on the right.

https://i.imgur.com/t2Ut1RJ.jpg?1

The bullet stuck in the chamber, you can see the unburned Unique powder.

https://i.imgur.com/VONOUf5.jpg?1

The bullet after I got it out, notice there's not a mark on the sides so it didn't go into the rifling very far.

https://i.imgur.com/mjDSOGK.jpg?1

[1Hawkeye]

It sounds like something is keeping the firing pin from striking the primer with enough force to set it off or the firing pin has broken. This will not cause a squib that was just a lack of powder in the cartridge. I would pull the breach block and clean the firing pin passage the check to make sure the pin and transfer bar are ok.

[David LaPell]

It sounds like something is keeping the firing pin from striking the primer with enough force to set it off or the firing pin has broken. This will not cause a squib that was just a lack of powder in the cartridge. I would pull the breach block and clean the firing pin passage the check to make sure the pin and transfer bar are ok.

Yep, did that, and it was pretty clean. I took the whole gun apart, checked everything out, it all seemed very clean and the firing pin didn't seem to be held up by anything.

[1Hawkeye]

Well if everything is clean and unbroken then it could have been a piece of grit in just the right place (gremlins) or maybe hard or older primers or their seating depth. With all the parts checked and cleaned I would check the primer seating depth and take another trip to the range to see if it happens again.

[bedbugbilly]

I know noting about the Sharps - so am just asking. Looking at your photos - is it normal for the firing pin strike to be that far off center? Any possibility that with the pin strike being off center that with that brand - or batch - it is not allowing a full strike on the anvil so that the primer fully functions as it should?

[Bent Ramrod]

When I first fired my Garrett Sharps carbine, I had a few failures to fire, and then by 20 shots or so, it was firing every time. I thought that maybe that U-shaped original style firing pin could have had the legs pinched slightly together, making the pin bind in its channels until a few hammer blows had straightened it out. No problems ever after.

The pin (or transfer bar) should be a very easy sliding fit, almost rattling loose, in the channel from all the way back to all the way forward. Protrusion out of the block should be 0.050” to 0.060”. A transfer bar design with a separate pin and the necessary return spring for same can sometimes jam against the cocked or twisted return spring, or the spring plus brass particles scraped from primers, if that is occurring, and so fail to protrude fully.

Finally, how is your mainspring? I got a Pedersoli Berdan Sharps with a wonderfully light cocking effort, even lighter than my slicked-up Shiloh. I wondered what master gunsmith had breathed his magic upon the mechanism until I discovered it did not often fire musket caps. Got a new spring from VTI which normalized the cocking effort for typical Italian replicas and the misfire problem went away. Nobody had messed with the original mainspring, as far as I could see. It was just weak, right out of the factory.

[Texas by God]

Try pushing up on the bottom of the breech block when you fire it. A friend had an IAC Sharps that had misfires because the lever wasn’t holding the breech block high enough for the firing pin to strike the primer correctly. Fitting a new lever solved it. Just a thought.

[Bad Ass Wallace]

Reduced loads in big calibres, I use Federal large pistol primers! These seem to be more reliable and a hotter flame than LR primers that I was using.
They even set off full black powder loads with ease.

[bgmkithaca]

I have had the same problem with my 50-70 and smokeless powder. It was low load density- sometimes boom and other times nothing. pulling the bullets showed poor ignition. Ended up using Dacron filler to keep the powder against the primer-cured the inconsistent ignition.

[Castaway]

Where’s the bullet on the pic of the unfired case? Did the primer detonate? Did it fail to fire or was this the case where the bullet entered the chamber and got stuck? A 50-70 case is cavernous and 12 grains of Unique can get lost in it. Could you have possibly turned the cartridge downwards leaving the powder charge towards the front of the case? This could result in erratic ignition. I’d try another powder with greater bulk, other than Trail Boss. Ideally, iBlack is the way to go but not always an option

[TCLouis]

Sounds like a way off answer, but are the primers fully seated?