What does this mean to you Primer sensitivity?

[Rule3]

I was looking at a a ad for some factory IMI 9mm ammo. It lists the following about primer sensitivity?? So is this a hard primer (hard to ignite or) what??

So at 9.5" a 55 gram weight will fire them at 2" it will not, how does that translate to something I can understand??

I have some light trigger CZ customs and regular springs in say a Sig.

PRIMER SENSITIVITY 55GRAM weight - 9.5" all fire, 2" not fire.

https://www.wideners.com/itemdetail.cfm?item_id=100001881&dir=

 

[243winxb]

Charles E. Petty-PRIMER SENSITIVITY Drop Test

there is an industry standard test for primer sensitivity. It's call a drop test. A primed case is placed in a fixture with the appropriate chamber that has a movable firing pin also of standard dimensions. A steel ball that weighs either two or four ounces, depending on the type of ammunition being tested, is suspended above the firing pin and held in place by an electromagnet. The height of the ball is variable. Depending upon the cartridge, there are three positions with different heights: no-fire, all-fire and half-fire. Typical no-fire heights are usually around 2" to 3". All-fire heights are more variable and range from a low of 15" to as much as 25". The half-fire height is determined by statistical analysis with a typical value being 5" or 6". Each manufacturer has its own parameters to judge the acceptability of a primer lot, but the test might use 25 primers at 1" intervals from the no-fire height until reaching a point where all of them pop. If that sounds complicated, that's because it is.

http://www.stevespages.com/primermyths.html There was a thread on THR in this forum with information, that i cant find. Velocity is what sets off* the primers, not how deep the pin penetrates into the primer. 55 grams is about 2 oz.

 

[Mad Chemist]

It means that >13Joules of energy will pop it and <2.74J will not.

It says nothing definitively about the interval between 2.74-13J.

This is terrible way to measure primer sensitivity. It requires multiple unit conversions. It also omits close to half of the values for J that likely lay on the normal distribution for values that actually ignite that particular primer.:banghead:

So scientifically speaking, it's purty dumb

I suspect that the manufacturer actually has a lot more data than the 2 points provided above. I also suspect that those two points probably represent points that are 2-3 std errors from the target amount of work required to pop the primer. But I can only guess because all we have are the 2 data points.

 

[243winxb]

Firearms accidental discharge-Primer sensitivity

The sensitivity of the primer relates to the firearm and accidental discharges if dropped.

6. Drop Test


The purpose of the Drop Test is to confirm (or deny) the likelihood of the sample being inadvertently fired through being dropped in the loaded con-figuration. This test is intended to replicate a dropped gun firing, exactly, without regard to physical damage of the test sample and the same risk of damage to the sample and alternate testing procedures discussed in Paragraph 5, above apply. Prior to initiation of this test a Primer Sensitivity Test of the ammunition will be conducted to insure the sensitivity of the primer is within acceptable commercial limits. The proper operation of the sample will be confirmed and a primed cartridge case (shotshell) of the appropriate caliber (gauge) without propellant but with a bullet (shotload) in place will be chambered in the test sample. The magazine of the test sample will be fully loaded with ammunition of the appropriate caliber whose bullet weights are - unless otherwise specified - the heaviest available on the commercial market in that caliber. The gun assembly is then to be subjected to multiple, controlled Drop Tests from a height of 42 inches designed to produce impacts with the centerline of the bore in each of its six cardinal positions. This will require a specially configured drop fixture to control the height of the drop, the orientation of the test sample at impact and the precise area or feature of the sample impacted. The following procedure utilizes one such fixture whose performance has produced acceptable results. The drop frame of the fixture will be raised to the desired drop height over a rigid, vertically - mounted, one inch diameter - hardened (290-320 BHN) steel rod and restrained at that point with an electromagnet. The test sample will be cradled on the drop frame with the desired impact location directly over the end of the steel rod. When current to the electromagnet is interrupted the drop frame cradling the test sample shall reach drop velocities within 2% of the free fall velocity from that height and will continue unimpeded six inches beyond the point at which the sample impacts the rod and is lifted from its cradle. One impact test in each of the six cardinal positions of the sample (muzzle up, muzzle down, right side, left side, top and bottom impacts) will be performed noting the condition of the primed case - fired or unfired - after each test. After completion of the sixth impact wherein no firing of the primer was recorded the condition of the primer will be noted and the test sample will be cocked and fired to confirm the suitability of the primed cartridge case. Any test which results in a "firing" will be noted, another primed cartridge case chambered in the sample and the test continued. The entire sequence of six impacts will be repeated with the hammer and safety in each of their designed positions and combinations thereof, i.e., safety on - hammer cocked, safety on - hammer down, etc. The precise feature of the gun impacted in each test will be that feature most likely to result in an inadvertent firing. The point of impact on all muzzle up tests will - unless otherwise specified - be the spur of the hammer on all samples with exposed hammers. On occasions the evidence may bear markings which indicate a specific feature of the gun was impacted in a dropped gun incident (bruises, abrasions, etc.). Samples of this type should be drop tested to provide for this impact orientation prior to conducting other orientations of Drop Testing.

http://www.firearmsid.com/Feature%20Articles/022001/HPWhite.htm I remember reading a 1911 would have to be dropped while standing on a step ladder to make it fire and then it would have to hit muzzle first.

 

[Rule3]

If that sounds complicated, that's because it is.

Thanks. It is pretty useless considering there is nothing to compare it to. Never seen this on any factory ammunition so who knows what it really means, It would be nice to know if the damn things just go bang in any gun.

Maybe it is an attempt to baffle us with BS and make it official sounding?

From the Steve's pages article:

Where it gets interesting is when you try to find comparative test data for the different brands. Nobody in the industry is talking. Obviously, the makers test competitor's products, but the only on-the-record response I could get was from a Remington executive who said, "there isn't much difference" in primers.

 

[Reloadron]

Actually the method of measurement (drop test) is fine. The problem comes when we can't acquaint the results easily to something. For example when hand loading ammunition we say Federal primers are sensitive but primers like CCI #41 are less sensitive. The problem becomes while we know the basics and which primers we like for specific loads we don't know where they would figure into the equation. I have no idea for example where a CCI 200 LR primer would fit in as to the force required to detonate it?

Here is an example of a Primer Sensitivity Tester.

SAAMI does mention:

SENSITIVITY TEST FOR PRIMED SHELLS OR PRIMERS
A method of determining the sensitivity of primed cases held in a specified die and subjected to a range of specified firing-pin blows imparted by a freely falling ball. Commonly called Drop Test.

Then if you really want to torture yourself there is this 1953 NAVORD document.

Mad Chemist sums it up nicely where he states:

It means that >13Joules of energy will pop it and <2.74J will not.

Ron

 

[Ironicaintit]

Without results comparing different brands and types of primer with a drop test, it doesnt tell us a whole lot.
Without comparative samples, the numbers do not tell whether it is more or less sensitive than others.

 

[243winxb]

Typical no-fire heights are usually around 2" to 3". All-fire heights are more variable and range from a low of 15" to as much as 25". The half-fire height is determined by statistical analysis with a typical value being 5" or 6".

9.5" a 55 gram weight will fire them.

I see a soft, sensitive primer???

 

[Dudedog]

I seem to recall Wideners said in the past that IMI 9mm HPs had hard primers
This is what they said about them.

This is ammunition has a very hard primer and it designed for the full sized pistols. It does not work well in the sub compact 9mm pistols.

(no primer specs for the HPs)

They don't seem to have this note on the FMJs.

 

[rcmodel]

I would expect IMI 9mm to have hard mil- spec primers, as most European 9mm has.

I don't know what all the mumbo-jumbo in the add means.

But you can bet they are harder to set off the Fed or Win primers.

rc

 

[Rule3]

I seem to recall Wideners said in the past that IMI 9mm HPs had hard primers
This is what they said about them.


(no primer specs for the HPs)

They don't seem to have this note on the FMJs.

Exactly!

They say the 115 FMJ will function in anything and there is no mumbo jumbo test results but on the 115 and 124 JHP they say it is a hard primer

"This is ammunition has a very hard primer and it designed for the full sized pistols. It does not work well in the sub compact 9mm pistols."

Oh heck I will call them.

 

[Rule3]

Just to simplify things, direct from Wideners: now why they could not just say that who the heck knows!!

They are a hard primer. They are harder than all the companies you listed. They are a Military primer made by S&B.

 

[fguffey]

I would say all bets are off because it is repeated over and over etc., the firing pin strikes the primer and then the case, powder and bullet take off when driven to the shoulder of the chamber. It is said the primer is busted when the case hits the shoulder of the chamber.

I have killer firing pins, I do not concern myself with sensitive primers. If I had an interest in determining 'the most powerful' I would test. My favorite primer is the Federal.

F. Guffey

 

[Mad Chemist]

I see a soft, sensitive primer???

You cannot derive that conclusion from the available info. The quote about the test's standard parameters (from Steve's Pages) does not indicate the mass of the impact weight.

The example you are comparing with (from Wideners) provides a mass of the impact weight as 55grams. You can't compare the standard test results for height of drop unless you know that the mass of the test weight is the same for both tests.

 

[iagbarrb]

Means: Trust well known primers. Avoid bad quality made in ch.. primers that can produce an accidental discharge if you drop wour weapon.

 

[Dudedog]

Wondering if the HPs have harder primers the the 115 RNs because the HPs were designed as submachine gun rounds.

The full size vs compact does not make a lot of sense just a generalization, just as striker fired vs hammer fired would be. I don't know but I would think you would probably be ok with most pistols with factory springs.
Just for fun one time I Ioaded a small batch batch of 9mm rounds with Tula .223 SRM primers to see if I would have issues. I had no problem in my Sig P226, Taraus PT99, Springfield 1911, or even my subcompact XD.
(this was a small sample I only tried about 10 rounds in each pistol)

If you have any SRM primers (or maybe even pick up a 100 to try) I might load a few rounds to test in whatever you are thinking about shooting the ammo in and see if you have issues.
So you would be testing a "hard" primer. No issues most likely = good to go.