Light strikes on primers, why?

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Guys, things just got weirder. My son-in-law went to the range today, taking along his S&W 686. His intend was to shoot the rounds that would fire and pull the bullets on the remainder.

Every round he pulled the trigger on from the same batch of reloads that fired 1/3 of the time, shot 100%.

Now I’m at a complete loss.
 
you just proved that the problem is not with your revolver (sort of); you also proved that the problem is not with the primer; the second hammer strike ignited all the primers that were fully seated with the first strike made with your gun.

seat all primers fully to the bottom of the primer pocket regardless of depth is the solution of your problem.

glad you got this one solved,

murf
 
murf said:
you just proved that the problem is not with your revolver (sort of); you also proved that the problem is not with the primer; the second hammer strike ignited all the primers that were fully seated with the first strike made with your gun.

seat all primers fully to the bottom of the primer pocket regardless of depth is the solution of your problem.

glad you got this one solved,

murf
Click to expand...

I have a feeling it is not "solved":):)
 
If he very carefully seats all the primers to the bottom of the primer pocket on a new batch identical to the last except for fully seated primes and they all fire, he knows what happened, if they still have issues in his gun and not his sons, he knows the issue as well.

Make a new batch being careful to seat the primers fully, hard into the bottom of the pocket vs being easy with them.
 
murf said:
you just proved that the problem is not with your revolver (sort of); you also proved that the problem is not with the primer; the second hammer strike ignited all the primers that were fully seated with the first strike made with your gun.
Click to expand...

This is why I asked in my previous post as to whether or not he tied to shoot them again.....in his gun. Trying them in another gun does not necessarily mean there is not an issue with the OP's firearm. Had they gone off the second time in the OP's gun, then we would know the issue is not his firearm. Going off in another firearm could mean the primers were seated too shallow or that the OP's gun does indeed have light primer strikes. For the issue to come up so quickly, and with only the usage of one set of components(new Starline brass and incorrect primers), my guess is it has to do with not seating the primers so the anvil is no pre-loaded. New Starline is notorious for tight primer pockets and putting a layer of nickle on top of that cannot help. Again, seating primers below flush assures one that the anvils are probably pre-loaded. RCBS hand primers, if not worn badly and the primer pin is correct, will certainly seat primers below flush. It just takes a heavy squeeze. One reason while late in life, I have gone to their bench mounted priming system.

There is but one S&W 686 involved in this entire weird story.
Click to expand...
You musta posted this as I was replying. In this case......you have your answer.
 
jski said:
There is but one S&W 686 involved in this entire weird story.
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When firing single action the firing pin strike is the hardest. Less chance of a misfire.

When firing double action, the strike is lighter. The hammer doesnt travel back as far.

Make sure the strain screw is turned in fully.

How was the gun being fired? Single or double?
 
jski said:
Guys, things just got weirder. My son-in-law went to the range today, taking along his S&W 686. His intend was to shoot the rounds that would fire and pull the bullets on the remainder.

Every round he pulled the trigger on from the same batch of reloads that fired 1/3 of the time, shot 100%.

Now I’m at a complete loss.
Click to expand...
jski said:
There is but one S&W 686 involved in this entire weird story.
Click to expand...

I'm confused about what gun(s) you tried them in.
 
Magnum rifle primers are going to have hard cups. That means you have just taken any slack out of the system. Any slight incompleteness in seating will rob power, and likely get a light strike. Any crud between the hammer and frame may slow down the hammer and generate a light strike. Any weakening of the main/hammer spring may cause a light strike.

Why are you using primers that are going to put the gun on the edge of reliability, such that any one thing going wrong will probably generate a failure?
 
Walkalong said:
That said, make sure they are seated to the bottom of the primer pocket.
Click to expand...
This. Your firing pin is probably pushing the primers deeper if they aren't bottomed out. That can look like a light strike.

Edit. Should have finished reading the thread before replying. Looking to hear the results of the next outing.
 
With a focus on primers and only primers. I agree with everyone who points out that we seat a primer till it bottoms out in the primer cup. This is driven by some pretty simple logic. Looking at Primer Pocket dimensions and tolerances. Small pistol and actually small rifle share the same dimensional numbers. Primer cup depth is 0.117" to 0.123" and primer height is 0.115" to 0.125". On average some never fired new Starline brass I have laying around has a cup depth of right around 0.120" and on average some CCI 500 small pistol primers laying around come in with a height of 0.117" and looking at the below image of some primers note how the anvils sit slightly above the cup.

Anvil%20Position.png

The anvils are just about 0.003" above the cup. That is pretty typical of all primers and they are made this way for the reasons already mentioned. The primers I just mentioned would need to be seated at least to a depth of about 0.003" below flush. While not handgun primers the below image is a good example of primers seated below flush. Using a white business card as a straight edge the gap is pretty noticiable.

Primer%20Seat%202.png

Anyway it's just more food for thought and as also was mentioned frequently a primer seated flush will not fire but the strike will further seat the primer so on a second strike the primer will detonate. Assuming a firearm in good working order and properly seated primers things should always go bang.

Ron
 
To add to @Reloadron and his excellent post, the legs of the anvil need to be touching the bottom of the primer pocket (Period), and you can seat them even further until the cup pushes over the legs and hits the bottom of the pocket as well and not hurt the primer. Some call this "pre-load" .

Ever bang on a nail in a board with no support for the board? Can't get that sucker in good, same thing, much of the blow is absorbed by the movement of the board. In the primers case, much of the blow of the firing pin is absorbed/wasted pushing the primer deeper.

I know better and I did it the other day, I used my old Sinclair hand primer I had not used in a long time and it wouldn't seat the primers past flush. Well, hard headed me said what the heck (Even though I have more hand primers) and shot them anyway. All went well for quite a few of them before they started misfiring and causing me issues. I re-seated the remainder of them (Don't do this at home boys and girls) .005 below flush with the new hand primer and bingo, issue solved. *Sigh* And I know better. :)

The 21st Century hand primer is simply awesome. I love the click adjustable head.
You can precisely control how deep each primer will be seated for match rounds.
Uniform the primer pockets, set the priming tool, and every single one will be the
same, no need to "feel" it hit bottom each time. Set it up and prime.
index.php


I can fix the Sinclair hand primer, I just need to take a piece of it out, chuck it up in the lathe, true it, and remove about .008 from it. If that is too much it has shims to handle that.
 
Texas10mm said:
There might only be one 686, but he talks about HIS L frame and his son's 686. That to me means two separate revolvers.
Click to expand...

Perhaps. maybe. maybe not? Apparently the OP doesn't know what model L frame he has? Gee could it be a 686??
This thread is just a cryptic rabbit hole.
I think it was Colonel Mustard, with the Revolver, in the Cellar!:barf:
 
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