Primer depth question

[aggiejet]

I am starting a new thread, although it relates to the person asking about CCI primers. I too had 2 outta 40 misfires last week on a 25-06 load using CCI primers. By naked eye examination, the two misfired primers appear to be seated deeper than the others. Using a caliper, I have determined that the misfired primers are barely below flush, like maybe .001/.0015 and all of the ones that fired are no deeper than flush. All that said, that is an incredibly small measurement, and I'm not real sure that I can discern a difference of .002 (see below)


My Lyman reloading manual gives a specific range of depth to optimal seat primers.

"Primers should normally be 0.003" to 0.007" below flush. Thus, strive to adjust primer seating for a nominal of 0.005" below flush. The exception to this is CCI primers which the manufacturer suggest be seated to a depth of 0.002 to0.004 inches below flush- a nomianl of 0.003 inch."

So based on that guidance, I am not getting the primer anywhere near where they need to be, although out of 100 reloads, we had "only" 3 misfires.

I am using a Pacific Power C reloader with Lee 3 piece dies and I have not purchased a head space gauge yet, although I will do so today. I prime with the priming tool that is pushed/inserted into the slot of the ram while the ram is lowered, seating the primer into the primer pocket.

I went on-line and downloaded a manual for this loader. The manual does not provide instructions on how to adjust the primer seating depth. Am I to believe that I am to rely on feel as I lower the ram onto the primer seating mechanism to find the correct depth? This doesn't make sense to me.

Additionlly, do the hand primers come with a means to adjust the depth of the primers, therefore an improvement of the current system, or are hand primers used primarily (no pun intended) to expedite the priming process and depth is a function of feel also?

Lastly, I know many will scoff at this search of knowledge, but I am just trying to learn how to do it right.

Thanks,
Mark

 

[rcmodel]

To be properly seated, the primer cup needs to be in direct contact with the bottom of the primer pocket.

That preloads the anvil into the primer pellet compound, making it ready to be fired when the FP hits it.

I never put much stock in "flush, below flush, .002" below flush, etc.)
All primer pockets are not all the exact same depth.
Especially with different brands of brass.
What's flush with one brand might be .003" below flush in another.

It matters not how 'flush' they are, as long as the primer cup is seated on the bottom of the flash hole.


No, the hand priming tools do not allow adjustment.

But the 'feel' is so much better then press priming you can easily tell when the primer cup hits bottom.

rc

 

[witchhunter]

I use a Sinclair primer pocket uniforming tool, maybe your primer pockets were not deep enough in your brass. Brass is one of the most inconsistent components in reloading. Primers could be bottomed out, unable to be pressed in any further. I use a hand primer, I like to feel the primers seat. It makes it easy to notice a loose one. Sounds like you are going about it correctly, asking pertinent questions. Good luck.

 

[Reloadron]

Take a look at this link. Those numbers are the SAAMI specifications for the case primer pockets and the actual primers.

Primers and case pockets vary from manufacturer to manufacturer and lot to lot within any given manufacturer. I seat primers till they bottom out, I know the primer anvil is flush against the bottom of the primer pocket of the case.

If we look at the allowable dimensions phrases like this:

"Primers should normally be 0.003" to 0.007" below flush. Thus, strive to adjust primer seating for a nominal of 0.005" below flush. The exception to this is CCI primers which the manufacturer suggest be seated to a depth of 0.002 to0.004 inches below flush- a nomianl of 0.003 inch."

Become a little without meaning. Now look at these dimensions by manufacturer.

Back to seat a primer till it bottoms out. Even with that we now get to the protrusion of the firing pin from the bolt face. A round that fails to fire in one gun may fire just fine in another gun.

Ron

 

[aggiejet]

Thanks all for a quick reply. That puts the debate in some context. I might add, I purchased a primer pocket tool and intend to clean/size(?) on this next reload. Also, just purchased a case gauge. I read RC's post somewhere about overworking the brass while resizing. Not real sure I don't have a little of that going on as well.

 

[Smokey Joe]

Primer seating...

Aggiejet--Don't think anyone on this forum will "scoff at your search for knowledge!" THR is all about SHARING knowledge, AFAIK.

Re: priming success or failure (in terms of getting all the rounds to go bang): My experience has been with a Lee Auto-prime, and now with a Lee Auto-prime II. I've always pushed the primers in until I feel them "bottom out." That feel is easy learn, BTW.

Started years ago with that method. Never knew that there was a recommended depth of seating below flush, nor that CCI primers had a special depth, until recently. Always checked to see that the primers were below flush, using the "educated finger" method.

Have never, to the best of my recollection, had a round FTF due to primer not being fully seated, or being seated too deeply. I use a variety of primer brands, including a lot of CCI's. I reload a variety of brands of cases, especially in .30 M1 Carbine, and .45 ACP, where I use virtually everything I can pick up.

Only way I can think of, that seating a primer too deeply could be a problem, would be if the firearm in question had a relatively short firing pin, and the deep-seated primer just didn't get hit strongly enough as a consequence.

Before going to a reloading press, I had a Lee "Hammer-it-in" kit. Hammered the primers to below flush with that, too--And occasionally set one off by excessive hammering (no harm done; at that point in the process the primer is surrounded by steel; primer goes bang, there's some smoke, and you deprime, resize, and continue) but there again, I don't think I ever had a FTF involving primer seating.

Bottom line: Make sure your primers are seated below flush, preferably bottomed in the primer pocket, and you're good to go, as far as I know.

 

[floydster]

I seat my primers till they don't go any farther wether it be on the press or hand priming--which I prefer.

 

[Tony k]

I'd get a hand primer. As others have pointed out, you can feel when the primer is at the bottom of the pocket. I have an RCBS hand priming tool. For every caliber except 38/357, I just squeeze it all the way down. All my 38/357 cases have shallower primer pockets and I just have to go slower.

Also, don't be concerned about asking questions on THR. I pretty new to reloading and I ask all kinds of newby questions, and have made my fair share of half cocked statements. If anyone gives me a hard time it's always good natured or tounge-in-cheek. Treating others with disrespect is the low road. Besides, wouldn't you rather admit that you don't know something and have someone edify you rather than be foolhardy and make a big blunder? Especially with something as potentially dangerous as reloading?

 

[cfullgraf]

I seat primers with a hand primer until they bottom out. My grip is not real strong so I tend to squeeze pretty hard. For some, this would be too much. You do not want to deform the primer cup. Too much deformation of the primer cup may damage the primer pellet.

Not very scientific but I have not had a failure to fire due to a mis-seated primer.

I am toying with a bench mounted primer at present and I will see with it.

 

[Blue68f100]

I press prime on my LNL-AP. You seat the primer till it bottoms out. It's very hard to crush a primer but can be done but they still will go bang. If they are not seated fully in the pocket you will get FTFire.....

 

[gamestalker]

I think your over thinking this. When you prime you can literally feel the primer bottom out in the pocket, and then a tad further and you can feel the pre- load. It doesn't matter how measurably deep they are, just make sure they are completely seated, don't be afraid to seat until you feel them pre-load.

And mixed brass is going to result in some requiring more or less depth, though a couple thou more than necessary won't hurt anything.

GS

 

[Rule3]

I concur with those that have posted just seat them till they hit the bottom. No measurements or calculating needed. Most calipers used for reloading are not capable of accurately measuring those .002 to .007" difference in a primer pocket anyway.
I prime on the press and have also used a LEE and RCBS hand primer. You just seat it it in there, It can withstand more force than most people think It will not go off. Sometime when I get rolling on the press I really "hammer" them in there, not intentionally and not enough to crush them. I do not clean primer pockets either. Wolf, CCI, Winchester, doesn't matter.

 

[45lcshooter]

I use Lee hand primer, you need to know how to feel the primer go into the case. Everything but 9mm gets hand primed, here. AR rounds, hunting rounds, plinking rounds, revolver rounds they all get hand primed. I have never went by the book for priming. As long as you have cleaned the primer pocket and reamed it out and even flash hole debur, you primer will go off when the trigger is pulled(unless you have water on your primers or such like stuff, I am referring to the white and black world) Ive primed 1000's and 1000's of rounds, hand priming and looking at each one and primer is below the surface, they all fired.

 

[stu1ritter]

I've been loading .32 S&W Long with all new StarLine brass on my Hornady LnL. I seat the primers hard against the bottom of the case (I think). I've had a few failure to fire on the first drop of the hammer but without fail they will fire on the second drop of the hammer indicating the primer wasn't completely seated, no matter how well seated I thought it was. I don't think I can push the press handle any harder when seating the primers and yet a few don't seem to make it all the way.
Stu

 

[ReloaderFred]

My standard is .004" below flush, and I don't have primer issues. For this, I use a press mounted RCBS APS primer seating tool, or in some cases the Ram Prime.

Hope this helps.

Fred

 

[dickttx]

On the ones that fired, they backed out of the pocket somewhat when fired, then were pushed back flush by the bolt head.

 

[Walkalong]

Better to seat them harder than softer. They should to be at the bottom of the primer pocket.

Not being seated deeply enough is the cause of 99.99% of primer failure.

 

[hartcreek]

I expected someone else to state this before now.....If you do not seat the primer all the way to the bottom of the primer pocket your fireing pin winds up doing it when you attempt to fire the round and you lose energy that should have been expended fireing the primer....seating the primer.

 

[aggiejet]

I expected someone else to state this before now.....If you do not seat the primer all the way to the bottom of the primer pocket your fireing pin winds up doing it when you attempt to fire the round and you lose energy that should have been expended fireing the primer....seating the primer.

I hadn't thought about that. That makes complete sense. I was concerned with too deep. Looks like not deep enough is more of a real concern.

So now I am more perplexed though as to why the 2 rounds didn't fire because I rechambered both rounds a second time and Neither fired. So if I had the primer too shallow, the firing pin seated the primer on the first trigger pull, I would think the second trigger pull would set it off.

Any other thoughts on why the rounds didn't fire?

 

[GLOOB]

Bottoming out is not enough. After you feel the primer bottom out, you should press just a little bit further. This fraction of an inch of movement is what pushes the anvil slightly into the priming compound.

If the primer cup is significantly flattened, you may have overdone it. But with CCI primers, I haven't found this to be a concern. You can't crush one those guys. As long as they're fully seated, they will fire.

They might not fire on the second attempt for a variety of reasons. The primer hole might be a little deeper on those two cases. You might wanna check your firing pin protrusion to make sure it's in spec. Also, your case might be sized too short for your chamber, contributing to a headspace issue. At any rate, now that there's a firing pin shaped dent in the primer, it might take a little more impact to ignite the primer. There's more surface area of metal for the firing pin to move, and some of the priming compound may have been pushed away.

 

[243winxb]

cci 400

I dont think there is such a thing as seating a primer to hard. I have smashed a few and they stll fired. One seated sideways is a different story. Its rare to get a bad primer, but may happen. A CCI 400 needed 4 strikes from a Savage Axis firing pin. Bullet was pulled after 2 pin strikes & powder dumped. Measurements showed head to datum decreased .014" Prime was placed in a 2nd case, did not fire (3th strike) , shoulder set back .006" The 4th time it fired. More testing showed the shoulder will be set back by the firing pin strike. A shorter head to datum measurement of .006" for a Savage Axis in 223 rem. Another shooter tested this over on AR15.com with his Axis, same results. This was the first problem with a primer not going off, on the first strike, in 40+ years from me.

 

[Walkalong]

I dont think there is such a thing as seating a primer to hard.

I agree. I have tried to "crush" a primer, and they just kept going bang. All but accuracy rounds for rifle I seat pretty hard. Even then I seat them firmly. Allen Hall told me once that as far as accuracy is concerned, if your primer goes bang, you don't have a problem. He's probably right.

 

[Reloadron]

Live by the Creed.

The lowly little primer:


Hand loading a 223 round today at current approximate prices including new brass cost about $0.69.

Primer $.04
Powder $.10
Bullet $.20
Brass $.35

The least expensive component and yet most critical is the primer. Heed the creed!

Ron

<EDIT> Provided as some humor </EDIT>

 

[hartcreek]

Evey time you handle a primer with your fingers the primer can be contaminated. When I first started reloading I used the ram primer that came with my kit.......man was that slow. I switchd to a handprimer twenty years ago and it sure increased my speed and eliminated primer problems. I use a RCBS that has the tray which one you get will depend on your color choice.

 

[Joe3of3]

What I learned...

I'm still learning reloading, and one of my .45's had failure to fire issues, while five other .45's did not. I learned to clean the primer pockets on the cases, then put the primer depth at about .005" (per the Lee reloading manual). I had been seating the Winchester primers to flush, or very slightly below flush.

Using a Lee Classic turret press, I have to give several extra pushes on the ram lever to get the proper seating depth...or use the Lee hand primer (with no powder in the case) to fully seat the primer.

Dirty pockets did affect primer depth, and some brands were slightly tighter fit for the primers and required a tad more ram pressure.