What primer depth should I look for with 38 special?

[Bruce H.]

I have been reloading 38 special on my Square Deal B for three-and-a-half years now. Recently I had some light strike misfires with my S&W 642. Most of the responses that I got on this Forum suggested that the primers were not completely seated. All of my other revolvers are either SA/DA or SA only, the 642 is the only one that I ever shoot double-action. I don't shoot the 642 too often, so I had not encountered this problem before. Today I got out the remainder of the batch of reloaded ammo that I had been shooting when I experienced the misfires and I measured the difference between the top of the primer and the case head with my caliper. On most of this batch of reloads the top of the primer was flush with the case head. Visually the primers looked like they were slightly below the level of the case head, but my caliper told me different.
I cleaned some brass today and started to reload some more 38 Special. This time I really slammed the primers into the cases using my Square Deal B. I wanted to make sure that there was no doubt that I was fully seating the primers. The primers look normal, they don't look mashed or damaged. I use WSP primers and the brass is a mixture of Winchester and S&B. After loading these new rounds I took my calipers and measured the difference between the top of the primer and the case head. I was getting measurements of 0.004-0.006". From now on I will begin measuring the primer depth as a normal part of my reloading checks along with OAL, crimp, powder weight,etc.
I took some factory Federal 38 Special +P JHP's and measured the difference between the top of the primer and the case head and got values of 0.001-0.002".
Is there a rule of thumb for what measurement I should shoot for with this primer seating measurement? Is 0.004-0.006" a good range for me to strive for or is this too deep? Is 0.001-0.002" acceptable or should they be deeper?

 

[ReloaderFred]

You're on the right track for curing your misfire situation. Ideally, they should be in the range of .004-.005" below flush. Of course, this measurement is going to vary some due to different brands of brass and primers. I've never loaded on the type of press you're using, so I don't know what the seating feels like, but on my Hollywood and RCBS single stage presses, I can feel when the primer has bottomed in the pocket.

The S&B primer pockets also tend to be on the snug side, which I find as a plus, but the depth of the pockets is the same as domestic brass. It's good brass and usually splits long before the primer pockets begin to get loose.

Keep experimenting and you'll find the right depth.

Hope this helps.

Fred

 

[Bruce H.]

Thanks for the answer ReloaderFred.

 

[The Bushmaster]

Yeh Bruce H. Ya gotta measure every one of those bast**ds to make sure each and very one is .004 to .005" below flush...

Just get them so they feel below flush when you run your finger over them.

Hi Fred...

 

[ReloaderFred]

Hi yourself, Bushmaster. With practice, he'll get the feel of it and won't have to measure anymore. I think I measured one last year, but it was just to satisfy my curiousity over a forum question.

Fred

 

[earplug]

Soft and hard primers

If you change to Federal primers your chance of a missfire will be less.
Federals primers take less of a whack to fire.
I have read that a slight crush fit is used for some DA only game guns that are set up for fast DA shooting games.
I have used Win WLP primers and they go bang with a 7 lb DA trigger on a N frame. Federals will go bang at 5-6 lbs.

 

[Bruce H.]

ReloaderFred, in answer to your question about what the seating feels like on the Square Deal B. It feels like a metal lever banging into a metal stop. The way that the Square Deal B seats the primer is by pressing on the press handle until the handle is stopped by a metal piece that sticks out of the front of the press frame. The metal stop is not adjustable, it is part of the frame. If I just push the handle with plenty of even force to the point where the metal stop contacts the handle I end up with the top of the primer flush with the head of the case. The only way that I can seat the primer below the case head is to bang the handle against the metal stop so that the front of my bench is lifted off of the floor. I am wondering if I can file down the metal stop so that I can just press the primer in with even force and not have to bang the handle against the stop. It is starting to make my elbow hurt. I am going to call Dillon tomorrow and talk to them about this. But I think that filing down the metal stop will be the answer.

I don't want to change primer brands because I have quite a few of the WSP primers.

 

[ReloaderFred]

Dillon will be your best source of information. They're familiar with the press and the adjustments. Usually, there is an adjustment in the seating post, and wouldn't require removing any metal from the press, but once again, I'm not familiar with your press. You shouldn't have to go to the lengths you are to properly seat the primers. It does sound like something's out of adjustment in the seating station, and should be easy to cure.

Hope this helps.

Fred

 

[.38 Special]

You've got to be a bit careful seating primers on the SDB, mate. There's a whole lot of leverage there. More than about ten pounds of pressure on the handle can crush the primer pellet, leading to -- wait for it -- failures to fire.

With most primers and most cases, light effort on the handle will result in primers seated to the bottom of the pocket, which is all you're really looking for. trying to get them all seated to exactly the same measured depth is actually counterproductive, as manufacturing tolerances result in properly seated primers varying in depth by several thousandths. (The late Creighton Audette of benchrest fame did an exhaustive study on this at one time.)

If you are really curious, buy a hand priming tool from RCBS or Lee and see what the primers look like when seated by hand pressure. Then find the minimum pressure in the SDB that results in the same conditions.

HTH!

 

[rcmodel]

I'm not familiar with all the working parts of a Square-D.

But it would seem to me filing on the handle stop to seat primers deeper, would also change the stop for all the other operations.

And that doesn't sound like a good plan to me.

rcmodel

 

[Bruce H.]

The mechanical stop is only used for seating primers. At this point I am going to leave things as they are.
I called Dillon this morning and talked to one of their technical people. He told me that the top of the primer is supposed to be flush with the case head. He said that the light strikes are the fault of the firearm, not caused by primers that are not completely seated.

 

[The Bushmaster]

The Dillon Tech is full of it. Primers must be seated all the way to the bottom of the pocket to work properly. Light hammer blows have nothing to do with an improperly seated primer except to seat the primer and on the second go-round fire the primer. Even a heavy hammer blow will have to seat the primer first...

 

[Captal_de_Buch]

My 2 cents

My J frame Model 60 will sometimes do light hammer strikes in double action mode.

If you get a light hammer strike in double action mode try that same round in single action mode. If it fires in single action mode the primer was seated properly.

The hammer doesn't go back as far in double action as it does in single action so it's not compressing the spring as much in double action and therefore less force is moving the hammer back.

My J frame is 100% in double action with Winchester primers. It gets a few double action light strikes with CCI primers.

The old Smith L frame revolvers can have the same problem if you crank the strain screw tension back on the mainspring. You can get a real slick double action but you'll get some rounds that won't fire.

If you are getting light strike misfires in single action mode then you've probably got a seating problem or you need a new mainspring.

 

[ReloaderFred]

I'm afraid you didn't get the best advice from the Dillon Tech, which is disappointing. The primer must be seated below flush in most cases.

Also, as Captal_de_Buch mentioned, you might check the strain screw on your revolver and make sure it's screwed all the way in and is tight against the grip frame.

If you have a misfire with the first hammer strike, and then the primer fires on the second or subsequent hammer strike, that shows that the primer wasn't seated all the way, and was simply seated the rest of the way with the first strike. The second strike will have enough resistance to set the primer off.

Hope this helps.

Fred

 

[rcmodel]

+1

Seating flush, below flush, .002" & 32/64's below flush, all have nothing to do with anything.

Some cases have less flash hole depth then other cases, even sometimes from the same manufacture.

And some primer brands are slightly different depth then others.

All that really counts is that the primer isn't sticking out above the case head, and is seated all the way in the primer pocket, with the anvil in firm contact with the bottom of the primer pocket.

Just exactly where that leaves the surface of the primer in relation to the case head by measurement is irrelevant.

rcmodel

 

[Spartacus451]

SDB priming issues? Oh boy that brings back memories.

Cutting straight to what I found out that even the Dillon techs don't know. The primer seating punch in the primer slide used to bear directly on the aluminum primer slide. The punch would eventually wear into the primer slide until it did not protrude high enough above the shell plate to reliably seat primers. This occurred after a bajillion rounds so you won't see it on a new press but you might find it in a used press that has been around for a while.

On new presses Dillon changed the primer punch so that its height was set via a set screw in the primer slide. That same screw exists in the old style primer slide but it is only there to retain the primer punch. I would take out the primer slide and primer punch and see if the primer punch matches the shape shown in the latest SDB manual. The old style punch has an hourglass shape at the bottom while the new style (if I am remembering correctly) has a uniform diameter narrow section at the bottom that the set screw fits into.

Also make sure that the shell plate is snugged down as tight as possible without impeding rotation. I started using Winchester primers because I found them significantly easier to seat than CCI primers. Filing the stop is a bad idea as rcmodel says. If you want the punch to protrude higher you can put a shim under the punch in the primer slide or adjust it with the set screw. You have to be sure that the punch (and cup) are not so high as to catch on the shell plate while it is indexing. There is a dimension given in the manual to guide you on this.

I'll also throw a plus one in for seating a primer to the bottom of the pocket.

 

[brickeyee]

Seating flush, below flush, .002" & 32/64's below flush

32/64 would be a half inch.

 

[rcmodel]

Yea, I know!
I meant it to be .002" & 1/2, or .0025".

It was supposed to be a little dry humor concerning measuring primer seating depth!

rcmodel

 

[ReloaderFred]

He was feeling frisky and was being satirical.........

 

[Mal H]

"I called Dillon this morning and talked to one of their technical people."
I never thought I would ever say this, but the Dillon "technical" person is wrong. The primer should be slightly below flush as most others have stated.

rcmodel's satire isn't wasted on me. I think the last time I actually measured the seating depth of a primer was well over 20 years ago. I can eyeball it to within .0001".

I use the RCBS hand primer and never worry about the operation or seating depth. Just squeeze the handle firmly to the stop and place the case in the tray - period

(Say, is that last statement the handloading equivalent of "Buy a Glock" when someone asks about a SIG? )

 

[The Bushmaster]

RCmodel...In over 20 years I have yet to find a primer pocket that didn't seat the primer below the case head...Yes...I know...You have been reloading longer then me so I will have to wait until I'm well into my next 20 years of reloading to find one that is flush...[2 & 32/64's...That works]

 

[AgentAdam]

Can you put the primer too deep? I can put them in from .004,.008 all the way to .017 deep.

 

[rcmodel]

Not too deep, but you can certainly crush them.

That's bad JuJu too!
Especially in Military semi-auto's!

Just seat them until you feel contact with the bottom of the primer pocket, then a little more to seat the anvil in the primer mixture.
Do Not crush or flatten the primer cup.

But .017" deep?
That sounds a little far out to me!

rcmodel

 

[Mal H]

adam - what priming mechanism allows you to seat a primer that deep?

 

[AgentAdam]

Believe it or not a Lee hand primmer but i was doing a test on purpose to see how much pressure it took for different depths and i was using two thumbs. I have really strong thumbs . Mechanics hands. I could go even deeper with a hornady hand primmer but that would probably flatten the tops a little. They looked pretty dang deep too but no signs of flattening. These were in .357mag shells. I only got .001-.004 in my 9mm.

Most brass would only go .015 deep max but these shells i picked up at the range with commy stars on the head stamp go up to .017 deep. Never did like that stuff anyways.

I'm not sure if i am measuring them correctly. I am just using the bottom depth measure of a cheap 6" OEM electronic dial caliper/micro meter.