Small Pistol and Rifle Primers

[matt]

This may be a silly question, but if I wait till after I load some .223 it will be a stupid question:

I remember reading somewhere that either you can use small rifle primers in pistol, or other way around. Is that true?

If they are the same dimensions, what is the difference between them?

EDIT: Please note that any load should be worked up slowly, particualarly when making deviations from "normal" practice as suggested in this thread. New reloaders should stick to the basics until they have some experience working up new loads with a chrony.

 

[Finalygotabeltfed]

FWIW, I use small rifle primers in all of my small pistol applications(mostly 9mm) and many shooters use them in .38 Super.

I do not use small pistol primers in rifle applications.
Although they are same dimension, pistol primers do not have as much energy as rifle primers and may not ignite a larger volume of powder as well as a small rifle primer.

I'm sure it could be done in a pinch, I just haven't been pinched that hard yet.

 

[Rob Boudrie]

The primer cup on small pistol primers is generally software as well, leading to primer flow with high pressure rounds.

 

[Finalygotabeltfed]

The primer cup on small pistol primers is generally software as well, leading to primer flow with high pressure rounds.

You're right.....I forgot about that Rob. Thanks for adding that.

 

[jhrosier]

The fact that the primers are nominally the same size does not mean that they can be randomly substituted.
The component makers actually do know what they are doing and would not make two different primers for rifle and pistol if it was not required.
The amount and brisance of the primer compound and the thickness and hardness of the primer cup are completely different for the two applications.
Substituting one for the other can lead to poor performance if you are lucky, and a destroyed gun and injury if you are not.
Suggesting otherwise, without warning of the dangers, is irresponsible.

Jack

 

[Scrivener]

The fact that the primers are nominally the same size does not mean that they can be randomly substituted....
Substituting one for the other can lead to poor performance if you are lucky, and a destroyed gun and injury if you are not.
Suggesting otherwise, without warning of the dangers, is irresponsible.

1. I have seen NO posts on this forum which suggest that primers "can be randomly substituted."

2. The use of Small Pistol primers in a rifle is admittedly imbecilic. So is using Large Rifle primers in a handgun, which almost guarantees a slam fire and all the Bad Things attendant thereto. This is no doubt why you will find no posts on this forum suggesting either practice, and several warning against it.

3. The use of Small Rifle primers in a PISTOL, however, is a proven procedure that enhances the safety of the load, IF properly worked up.

 

[jhrosier]

......
Use of Small Rifle primers in a PISTOL, however, is a proven procedure that enhances the safety of the load, IF properly worked up.

I will have to ask for a reference to any credible data that would show how using rifle primers in a pistol could result in an increase in the safety of an otherwise safe load published by any component maker.

If you are suggesting that an unsafe load can be made safe by substituting a rifle primer for a pistol primer, please refer to my last comment. I don't think that the context of the discussion embraces "wildcatting."

My last comment is not negotiable:

Substituting one for the other can lead to poor performance if you are lucky, and a destroyed gun and injury if you are not.
Suggesting otherwise, without warning of the dangers, is irresponsible.

Jack

 

[Finalygotabeltfed]

I will have to ask for a reference to any credible data that would show how using rifle primers in a pistol could result in an increase in the safety of an otherwise safe load published by any component maker.

If you are suggesting that an unsafe load can be made safe by substituting a rifle primer for a pistol primer, please refer to my last comment. I don't think that the context of the discussion embraces "wildcatting."

My last comment is not negotiable:


Jack

Reference 1:

I substitute small rifle primers for small pistol primers in my 9mm ammunition because I use the vast majority of my 9mm in an open bolt subgun. Having a harder primer cup with the small rifle primers adds a slight margin of safety to these rounds as it may prevent a slam fire that might occur with the softer cup of a pistol primer.

 

[Scrivener]

I will have to ask for a reference to any credible data that would show how using rifle primers in a pistol could result in an increase in the safety of an otherwise safe load published by any component maker.

Not all of us operate in the narrow confines of factory loads for factory guns. Some of us actually develop our own loads for our own guns - and do so without the unanticipated, energetic disassembly of the guns in question.

Some of us are also capable of realizing that a thicker primer cup necessarily increases the pressure which would be necessary to rupture that cup over a thinner-walled cup.

Ergo, I stand by my assertion that use of a Small Rifle primer in a duly developed pistol cartridge DOES increase the safety factor. Hence the widespread adoption of this practice among USPSA reloaders.

If you are suggesting that an unsafe load can be made safe by substituting a rifle primer for a pistol primer, please refer to my last comment.

I made no such suggestion, nor do I recall anyone else making it.

My last comment is not negotiable

How convenient for all of us. Neither I nor anyone else on this thread entered into a "negotiation" with you.

 

[Rob Boudrie]

I will have to ask for a reference to any credible data that would show how using rifle primers in a pistol could result in an increase in the safety of an otherwise safe load published by any component maker.

You've gone and add a qualifier of "published load", and later state that these comments to do not pertain to "wildcatting". No where in the Scrivener's comments did he qualify his statements to indicate they were restricted to published loads - which already contain safety margins. You based your rebuttal on a question that is more narrow in scope than the one that was actually being asked.

It's very common for reloaders with guns that have an appropriate fully supported chamber of modern manufacture to load 38 super (and variants), and 9mm to higher than standard pressures. It's also common to load 9mm and 40S&W to longer than SAAMI specs for certain guns (in fact, some manufacturers recommend it).

I've seen primer flow with small pistol primers that was not present with small rifle primers in the same gun and load.

 

[jrbtzx12r]

.

 

[EddieCoyle]

So is using Large Rifle primers in a handgun, which almost guarantees a slam fire and all the Bad Things attendant thereto.

The exception to that rule being the S&W .500 and .460 magnums which require a large rifle primer to accommodate the ungodly pressure therein. Those cases feature a deeper primer pocket for the LR primers.

 

[jhrosier]

I can't imagine what part of sticking with published loading data and suggesting the same for new handloaders that you fellows find so hard to accept.

My point is, that it is not responsible to tell inexperienced handloaders that it is OK to substitute components, unless you also explain the possible dangers involved.

Scrivener,
If you feel that you are experienced or lucky enough to chart new territory, that is fine. I simply don't agree that the fact that you have not blown yourself up is a credible data point, or a probable good defense argument in a liability case. In stead of getting your hackles up, you might have chosen to explain where your data originated. We do not have to be in complete agreement to have a dialog, but it is very helpful if everyone is polite when disagreeing.

So, if you are going to take beginners with you, on your adventures in handloading, please make sure that they understand the possible side effects.

Rob,
You have made a good point and I am sure that you can cite your references to the common practice of exceeding published loading data in some shooting disciplines.
You have also included a warning to the effect that the practice is only acceptable under certain circumstances. (Sounds like a qualifier to me.)
Empirical data is acceptable when when the test conditions are clearly defined.

Still...
It is problematic to determine when and whether and how to pass this sort of information to someone who might not have the experience or good judgement to use it safely. This is the basis for my (still) non-negotiable stance regarding not suggesting deviations from published data without warning of the possible dangers involved. It really doesn't seem like too much trouble to try to look out for the other guy.

Jack

 

[Chris]

Whatever you do, don't load small pistol primers in a caliber that will be fired in a gun that has a floating firing pin (a-la AR15s)

The inertia of the pin as the bolt closes usually dents a rifle primer, but could easily detonate a pistol primer.

 

[jhrosier]

Reference 1:

I substitute small rifle primers for small pistol primers in my 9mm ammunition because I use the vast majority of my 9mm in an open bolt subgun. Having a harder primer cup with the small rifle primers adds a slight margin of safety to these rounds as it may prevent a slam fire that might occur with the softer cup of a pistol primer.

Two questions, if you don't mind:

Isn't an open bolt subgun a slamfire anyway? I'm only familiar with guns like the Sten and Mac-10 that have a fixed firing pin. Are there other subguns that drop the bolt and then have a separate striker to fire the gun?

Is there a problem with slamfires with factory loaded pistol ammo in the subguns and are pistol primers that are available to handloaders softer than the ones used in factory ammo?

Thanks, Jack

 

[Finalygotabeltfed]

Two questions, if you don't mind:

Isn't an open bolt subgun a slamfire anyway? I'm only familiar with guns like the Sten and Mac-10 that have a fixed firing pin. Are there other subguns that drop the bolt and then have a separate striker to fire the gun?

Is there a problem with slamfires with factory loaded pistol ammo in the subguns and are pistol primers that are available to handloaders softer than the ones used in factory ammo?

Thanks, Jack

Jack,

A slam fire is usually in reference to an unintended discharge when a bolt is stripping a round off the top of the magazine and chambering it causing an out of battery detonation. It can happen in any type of semi auto gun but is most common in the M1A/M14 and SKS families of guns because of debris in the floating firing pin channel. Having harder primer cups can reduce the hazard and checking to see that primers are seated below flush in any reloads being fired in these(or any gun) is a must.

I'm pretty sure that the primer cups of factory pistol ammo are the same hardness as those available to reloaders with the exception of some military ammo designed for both pistol and subgun use.

An open bolt gun like the Uzi with a heavy bolt and a fixed firing pin flying forward can increase the likelyhood of a slamfire so I use a harder primer in the event that a primer isn't seated properly when reloading.

I have used small pistol primers for my subgun ammo without incident but I now use small rifle almost exclusively for that added hardness of the cups. I also inspect my ammo carefully before its placed in a can for shooting.

 

[Scrivener]

I can't imagine what part of sticking with published loading data and suggesting the same for new handloaders that you fellows find so hard to accept.

My point is, that it is not responsible to tell inexperienced handloaders that it is OK to substitute components, unless you also explain the possible dangers involved.

And just what "possible dangers" are posed by the one substitution in question; i.e., using SR primers instead of SP primers?

Note that:

1. There was NO mention of using Magnum primers OR substituting ANY other primer for any OTHER primer. The suggestion was solely for use of SR instead of SP primers.

2. Research provided on this forum shows that the only effect of that one substitution is a few more fps; hardly a dangerous condition, especially where the object of the exercise was to make the load more resistant to primer cup failure.

If you feel that you are experienced or lucky enough to chart new territory, that is fine. I simply don't agree that the fact that you have not blown yourself up is a credible data point, or a probable good defense argument in a liability case. In stead of getting your hackles up, you might have chosen to explain where your data originated.

Instead of lecturing us against leading newbies towards the dark side, you might actually read what was posted. It included the reasoning and the source for this well-known practice and the benefits obtained thereby. Note that this issue was ALSO discussed, at length and with links to yet another discussion, in a very recent thread:

http://northeastshooters.com/vbulletin/showthread.php?t=35182&page=2

So, if you are going to take beginners with you, on your adventures in handloading, please make sure that they understand the possible side effects.

That was explained. The substitution of one specific component for another specific component for a very specific reason. Everyone, except you, seems to understand the concept. I suggest that you are over-reacting to a misunderstanding.

 

[matt]

Guys,

Thanks for the feedback and advice. Good stuff. My reasoning for asking the question really comes from (2) things:

1) I'm almost of out SP primers
2) I'm about to start loading .223 for the first time and I would prefer to have only one small primer (SR in this case) and work loads around it to prevent accidentally mixing up primers in the future.

For Jack: I can see how you'd be concerned that an novice reloader who didn't know enough to investigate and work up a load properly might be led astray if they weren't paying attention. I'll edit the top post to include a statement about this for the benifit of future viewers.

Thanks again guys,
Matt

 

[Scrivener]

I just loaded 300 .40 S&W cartridges using SR primers.

Again.

Make that "per usual."

Deploy the blast shields.....

 

[matt]

Deploy the blast shields.....

 

[dingbat]

Just got off the phone with the folks who make CCI primers because I was researching the same question. Don't know about other brands but between the CCI small pistol 500 and small rifle 400 primers there are three significant differences.

1) Amount of explosive. The small pistol primer contains approxomately 23mg of explosive where the small rifle primer contains approximately 27mg of explosive. That's about a 17% increase and, according to the gal I spoke with, will cause significantly higher peak pressures. She also said that the smaller the case size, the more severe the effect will be.

2) Height of primer. The small rifle primer is 2 thousanths of an inch taller than the small pistol primer.

3) Bottom of cup thickness. The small rifle primer has a thicker cup bottom than the small pistol primer.

I'd like to point out that she was not being alarmist or over "lawerly" when telling me any of this. Just matter of fact that there is a difference and I'd be in uncharted territory if I chose to swap one primer for the other.