2 Firing Pin Hits?...

[BCB]

I have never seen this before…

The load is 19.5 grains of Lil’Gun, a CCI-350 primer and a 45-270-SAA boolit shot in a Ruger Blackhawk…

I was also shooting reloads today using Unique and Trail Boss and did not get the double strikes—if that might be what it is…

Any thoughts?...

(Should this be posted on another forum?)

Thanks…BCB

[S.R.Custom]

Looks like your cylinder is jumping out of time with the heavy loads after the initial hit. The ghost hit looks like it's probably a recoil induced hit from the hammer bounce after the first hit.

[missionary5155]

Good afternoon
I would think the hammer is rebounding after the initial primer impact and hitting the firing pin again. Must be a whole lot of inertia at play with that load in that reveolver.
What is the barrel length ?

[BCB]

Looks like your cylinder is jumping out of time with the heavy loads after the initial hit. The ghost hit looks like it's probably a recoil induced hit from the hammer bounce after the first hit.

If the cylinder is jumping out of time, is this a problem?...

This handgun has had only a grand or so of rounds put through it--maybe not that many...

Thanks...BCB

[BCB]

Good afternoon
I would think the hammer is rebounding after the initial primer impact and hitting the firing pin again. Must be a whole lot of inertia at play with that load in that reveolver.
What is the barrel length ?

The barrel lenght is a 6 incher...

The Lil'Gun loads do have considerable recoil, but this is the first this has happened...

Thanks...BCB

[S.R.Custom]

If the cylinder is jumping out of time, is this a problem?...


Sort of... It's not desirable...

Without having the gun in front of me, it's hard to speculate as to why it's happening. A weak bolt spring? A problem with the pawl? Grub in the cylinder notches? Mis-alignment of chamber & bore? An improperly fit cylinder?

A lot of things could cause it; heavy loads in and of themselves would not be the cause. Better have a Ruger savvy smith check it out.

[44man]

More common then you think. Mostly caused by hammer bounce with a replacement mainspring or one not strong enough. We have caught it in pictures.
The hammer is coming back far enough to drop the cylinder lock, allowing some turn.
I don't think it is recoil induced, but internal primer pressure against the pin.
The S&W will even do it.
Some powders are worse then others depending on initial pressure rise but even flash holes that are too large in a few cases will do it.
Why are you using Lil-Gun anyway? Showing a secondary primer strike as deep as the initial one means the hammer is going almost to full cock. Trigger position might limit cylinder turn with a Ruger but remember the old Colts with firing pin holes too large? They could fire twice with one trigger pull. The large holes could not limit primer push back and a punctured primer made it worse.
After market, light mainsprings are items for some thought too.

[S.R.Custom]

...I don't think it is recoil induced, but internal primer pressure against the pin.

The primer hits don't indicate that, and the primers themselves give no indication of over pressure. In fact, they look absolutely healthy.

[BCB]

44Man,

Just curious as to why you inquired about Lil'Gun...

It is a fairly heavy load and there is considerable recoil...

Is that what your concern with Lil'Gun is?...

BCB

[GBertolet]

I had the same problem with my 29 S&W. It's the inertia of the recoil, being severe enough to unlock the bolt, allowing the cylinder to rotate slightly, due to the torque generated in firing. The bounce back of the hammer makes the small hit. For this instant, the cylinder is misaligned, hence, the off center secondary hit. It has nothing to do with the pressure of the ammo. It is caused by a sharp heavy recoil overcoming the strength of the bolt spring. There are two solutions that I am aware of. First get a heavier cylinder bolt spring. Second, would be to change your load. Trial and error will determine your load. I bought a Wolff cylinder bolt spring , which fixed my problem.

[44man]

I had the same problem with my 29 S&W. It's the inertia of the recoil, being severe enough to unlock the bolt, allowing the cylinder to rotate slightly, due to the torque generated in firing. The bounce back of the hammer makes the small hit. For this instant, the cylinder is misaligned, hence, the off center secondary hit. It has nothing to do with the pressure of the ammo. It is caused by a sharp heavy recoil overcoming the strength of the bolt spring. There are two solutions that I am aware of. First get a heavier cylinder bolt spring. Second, would be to change your load. Trial and error will determine your load. I bought a Wolff cylinder bolt spring , which fixed my problem.
That is true with heavy recoil in the S&W from using heavy boolits. The lock inertia can unlock the cylinder and allow it to turn. But that has nothing to do with hammer rebound.
The pictures we took of single action guns had not even started up in recoil but showed muzzle flash with the hammer back almost to full cock.
It is HAMMER POSITION that unlocks the cylinder to get a second strike on the primer.
It has nothing to do with pressure either but mainspring strength is important to limit hammer rebound. If you take ANY revolver and drop the hammer on an empty chamber, you will see ZERO hammer rebound even with high speed photos. Shoot a live round with a weak mainspring and you will see the hammer rebound before recoil.
Where does it come from? The primer of course!
Here is a primer shot in a S&W with a below max load with a light boolit.
It only takes a bump from the primer and it will not show high pressure.
This will not affect the gun in any way but a weak mainspring can reduce accuracy due to not enough primer impact.

[44man]

44Man,

Just curious as to why you inquired about Lil'Gun...

It is a fairly heavy load and there is considerable recoil...

Is that what your concern with Lil'Gun is?...

BCB
My experience with Lil-Gun shows it burns very hot and can heat the barrel fast and erode the forcing cone and rifling just past it. It has little flame deterrent on it. That is why it can increase velocity without more pressure.

[BCB]

44Man,

I have also read the about Lil'Gun, but I was never sure about it. Many times rumors get spread like wildfire on the Internet. But I do think there might be some credibility to it...

So, it appears there might be a couple of thougts as to what is actually happening. The pic you posted is exactly what my fired cases look like. But, I guess that is what one would expect if the problem is the same...

So, since it didn't happen with Unique or Trail Boss, is lighter loads the solution? And the double strikes will just have to be accepted?...

This is the first time this has happened. Has something weaked in the handgun?

Confussed...

But, thanks to all who replied...

I shall continue to read...

BCB

[44man]

44Man,

I have also read the about Lil'Gun, but I was never sure about it. Many times rumors get spread like wildfire on the Internet. But I do think there might be some credibility to it...

So, it appears there might be a couple of thougts as to what is actually happening. The pic you posted is exactly what my fired cases look like. But, I guess that is what one would expect if the problem is the same...

So, since it didn't happen with Unique or Trail Boss, is lighter loads the solution? And the double strikes will just have to be accepted?...

This is the first time this has happened. Has something weaked in the handgun?

Confussed...

But, thanks to all who replied...

I shall continue to read...

BCB
The load does not mean much but your mainspring might have weakened. Lil-Gun might develop more right at the start and add to internal primer pressure, enough to bump the pin more.
It could also be the brass you use and the flash hole size.
It is not much to worry about.
I shot my SBH a LOT at IHMSA and for practice and I would see accuracy start to drop off so I would send to Ruger for new mainsprings. I supposed I changed them once a year.
Now I use Wolff over power variable springs. I use the 26# spring in the Ruger's and BFR's.
Standard springs are 22# to 23# but if you compare a used one to a new one, you will see how much set a Ruger spring takes. They get pretty short.
You have to stop and think about recoil. The gun is coming back AGAINST the hammer so hammer inertia is holding it to the frame. There are no parts in a Ruger that move forward under recoil.
Once recoil is over, the hammer does not have weight enough to keep going back plus spring pressure should hold it in place.
Double strikes happen before recoil even starts.
Freedom arms has said to NOT use Lil-Gun, it damages the gun.
I shoot heavy boolits in my .44 SBH, up to 330 gr with good charges of 296. 99% of my loads have been heavy for IHMSA and deer. Recoil is severe and after over 61,000 loads, I have never had a double strike.

[dla]

I've had the same thing happen with my S&W329pd. I don't really understand the mechanics of it yet and I've only had it happen when shooting in the cold weather. My loads are within powder manufacturer's published specs and verified over my Chrony. I pretty much only use Ramshot Enforcer with 270gr cast @1150fps.

https://sites.google.com/site/hobbyhintstricksideas/_/rsrc/1293931543941/Home/s-w-329pd-info/IMGP2692_small.JPG

[MtGun44]

Wow. That left one has THREE hits, each smaller.

Bill

[dla]

That is true with heavy recoil in the S&W from using heavy boolits. The lock inertia can unlock the cylinder and allow it to turn. But that has nothing to do with hammer rebound.
The pictures we took of single action guns had not even started up in recoil but showed muzzle flash with the hammer back almost to full cock.
It is HAMMER POSITION that unlocks the cylinder to get a second strike on the primer.
It has nothing to do with pressure either but mainspring strength is important to limit hammer rebound. If you take ANY revolver and drop the hammer on an empty chamber, you will see ZERO hammer rebound even with high speed photos. Shoot a live round with a weak mainspring and you will see the hammer rebound before recoil.
Where does it come from? The primer of course!
Here is a primer shot in a S&W with a below max load with a light boolit.
It only takes a bump from the primer and it will not show high pressure.
This will not affect the gun in any way but a weak mainspring can reduce accuracy due to not enough primer impact.

This makes a lot of sense to me. Thanks for sharing.

I've video'd the recoil from my 329pd, from the shooters view, and you can see the gun torque counter-clockwise quite violently. So when the hammer has bounced back far enough to unlock the cylinder, the frame twists past the cylinder a bit causing the return strike to be slightly to the left of the firing strike. I can see that this is really of no concern.

[dla]

By the way, you might find this Youtube video of a Colt Python firing in super-slow motion interesting. Even though it is a 357 mag, you can clearly see the hammer bounce.
http://www.youtube.com/watch?v=K-cCmWWM8ew&feature=related

[44man]

The recoil induced cylinder unlock with the S&W can be a problem.
The cylinder can rotate back far enough so your next trigger pull can be on the already fired chamber so you just get a "click."
Not nice with a bear or BG.
Heavier boolits from 265 gr up seem to be the worst offenders. Just needs a heavier cylinder latch spring.

[Matthew 25]

Thanks for the video dla.
Thanks for the explanation 44man.