Regular vs. MilSpec vs. Magnum Primers

[Gary L. Griffiths]

I have been reading conflicting information on using regular vs. MilSpec vs. Magnum primers in loading for .223 in the AR Platform. A couple of months ago, I bought a carton of CCI-41 primers, which seemed to be actually giving a slightly lower average velocity than regular CCI-400s. Finally, a week ago, I managed to find a box of CCI-450 primers, so I decided to test the three types of primer.

To test the primer variance, I loaded 30 rounds of .223, using new Lake City cases with 25.0 gr. AR-Comp under a Hornady 55-gr. V-Max bullet. Ten of the cases were primed with CCI-400s, ten with CCI-41s, and ten with CCI-450s. All charges were weighed on my new digital scale. I shot them this afternoon, recording the velocities with my new (to me) CED Millennium chronograph with the following results:

The CCI-400 standard primers gave an average velocity of 3054.40 fps, with a SD of 19.31.

The CCI-41 MilSpec primers gave an average velocity of 3068.90 fps, with a SD of 13.83.

The CCI-450 magnum primers gave an average velocity of 3054.60 fps, with a SD of 11.01.

In this test, the MilSpec primers proved slightly hotter (but only by 14 fps) than either the standard or magnum primers, and the magnum proved to be the most consistent.

As a check of my chronograph under the same weather conditions (mid-60s) I fired 10 rounds of Wolf Gold 55-gr. .223, which averaged 2982.80 fps, SD 28.09, and 10 rounds of Carl Gustav 62-gr LAP 5.56mm, which averaged 2980 fps, SD 12.82.

It would seem to me, that at least with AR-Comp powder, there is little difference between the three types of primer in terms of velocity, and virtually no difference between CCI standard and magnum primers.

FWIW

[arizona98tj]

While I didn't use CCI-41 primers, I performed the same test you did using 6.5 Grendel cartridges. I had virtually the same results....so close that my next trip to the range shooting the same two loads would yield results that were probably a few FPS different than the last ones shot. In other words, it made no difference for the bullet and powder combo I was using.

[jepp2]

I shot them this afternoon, recording the velocities with my new (to me) CED Millennium chronograph with the following results:

Interesting and thanks for sharing.

I run a lot of my loads over a chrony. Even with low SD, running 10 shot strings of the same load will typically show more variation than you would expect. If you ran your same test again, you might be surprised to see results change. I would still expect them to be close for the 3 flavors of primers, but the milspec might not be the highest velocity. And the CCI 41 and 450 are exactly the same primer mixture, only the anvil distance being different.

[chiefr]

Most of us know there are regular primers and magnum primers. Both have been around for many years. MilSpec, well I for one don't know much as they have appeared only recently.


I am trying to think if there was a milSpec ever for primers. Can't recall one from my time in uniform. Been out for a while now.
All types of milSpecs on small arms ammunition, but on the primer itself; I have my doubts.
Right now, me think "milSpec" primers are a sales gimmick, unless some of the younger guys who still serve can clue me and others in.

.

[Bart B.]

There are specifications for military small arms primers:

http://www.everyspec.com/MIL-SPECS/M...10E.045625.pdf

Other specs are listed in that document.

[pathdoc]

AS a user of this bullet, albeit in a bolt gun, I have to ask the obvious question: was there any meaningful effect on group size or impact point of switching primer with no other changes?

[Slamfire]

It would seem to me, that at least with AR-Comp powder, there is little difference between the three types of primer in terms of velocity, and virtually no difference between CCI standard and magnum primers.

Might very well be. I talked with CCI a long time ago and what I understood was the major difference between their Mil Spec primer line and commercial was sensitivity. It took more energy, on the average, to ignite mil spec primers. I was told that the CCI #41 (and I assume the CCI #34) were a magnum primer, but I too, have chronograph tests were the standard primers (I think WLR) produced gave a higher velocity than CCI #34’s.

Primer cake is mixed by hand, it is made of a mixture of components, with +- percentages in the mix, you would expect primer energy to vary. There is more sophisticated equipment than any home reloader can own, I was told these were called “Mules”. The Mules are highly instrumented test stands that can measure basically everything, from flame duration, amount of material ejected, temperature, pressure wave, etc. I was told these are used in the Army Ammunition plants.

The next lot of primers, your results might very well be shuffled.

It might very be that CCI is using the same primer mix for its mil spec line and its commercial line.

I am trying to think if there was a milSpec ever for primers. Can't recall one from my time in uniform. Been out for a while now.

There are those who call "mil spec" primers a gimmick. The guy who started this is a CCI hater, and thus this is hate speech. I have a #41 drawing, but here is the #34 top level drawing.



There are mil spec primers, always has been, when the military ordered ammunition which the primer characteristics were not specified, they got slamfires with their M16’s.

Commercial primers are supposed to meet SAAMI specifications . I have not seen any SAAMI primer specs so I suppose there is a sensitivity specification but I doubt, little else. Military primer cake is a specified mixture, commercial primer cake is whatever the manufacturer wants to do, and is a highly guarded secret. Call it “proprietary”. SAAMI specifications are voluntary, if the primers are a little too sensitivity, dimensionally off, maybe something else is out of spec, the primer manufacturer has to decide whether to lose profit by scrapping the lot, or shipping the lot. Based on discussions with QA reps in other industries, since the Consumer can’t tell the difference between good and bad, and the costs of dealing with complaints is always less than the cost of scrapping, guess which option is most likely picked?

In so far as military spec primers, here is a chunk of history on the #41 mil spec primer.

http://www.dtic.mil/cgi-bin/GetTRDoc...f&AD=ADA953114


Primer Sensitivity

Initial Specifications. Ammunition specifications established by the Air Force on 24 January 1963 provided for quality control against cocked, inverted, loose, and nicked primers. The specifications further provided for inspection and test of waterproofing
and the crimp of primers. However, the specifications did not provide for specific limitations on primer sensitivity for 5.56mm ammunition.-

Development. At the first meeting of the Technical Coordinating Committee on 26 March 1963,16 / the Air Force representatives submitted a list of reported ammunition deficiencies, which included "high primers" and "primers too sensitive". It was agreed that Frankford Arsenal would investigate the matter and recommend corrective action.

One of the malfunctions reported by the Air Force was the premature firing of cartridges that occurred upon initial charging of the M16 rifle with a cartridge from the magazine, or upon singleloading of a cartridge directly into the chamber, or when two rounds were fired at one trigger pull during semiautomatic fire.

On 17 September 1963, the Army Staff informed the Project Manager that the primer sensitivity limits contained in the specifications could not be accepted because of the risk of inadvertent fire. The Commanding General, USAMC, stated that the only practical solution was to modify the weapon. As a result of the Army action, USAMUCOM was directed to suspend procurement of one million rounds of 5.56mm M193 ball cartridges for the Army2 2/ until the problem was resolved. Solicitation of bids for the balance of
FY 1964 Army and FY 1964 U.S. Air Force orders were held in abeyance. In the meantime, on 3 September 1963, the Ammunition Procurement and Supply Agency (APSA) was advised that Olin-Mathieson and Remington, the only two eligible bidders for production of 5.56mm ammunition, had both taken exception to the technical data package. Both companies recommended changes to the primer sensitivity requirements. A meeting was held at Frankford Arsenal on 5 September 1963 with representatives from USAMCOM, APSA, and the two producers to resolve these disagreements. As a result of this meeting, Frankford Arsenal developed supplementary changes in primer sensitivity requirements in the technical data package. The requirement was established at a minimum of 12 inch-ounces and a maximum of 48 inch-ounces. As previously stated, however, on 17 September 1963, procurement would be suspended until the overall problem could be resolved.

Remington Arms Company, on the basis of the information contained in the Frankford Arsenal First Memo Report, undertook the design of a new primer that would be less sensitive and less susceptible to the inadvertent energy delivered to the primer by the free-floating firing pin of the AR15 rifle. Since it is difficult to adjust primer sensitivity by chemical changes, Remington elected to accomplish the desensitization" by increasing the mechanical strength of the brass primer cup, which must be indented by the firing pin to cause ignition.


Primer Composition
Initial Specifications. Ammunition specifications established by the Air Force 24 January 1963 did not restrict the chemical composition of primers to be used in 5.56mm ammunition.

Development Efforts.

Colt's Inc., first experienced difficulty in 1963 in complying with the 6,000-round endurance test for the Air Force contract.- / Specifically, the problem was defined by Colt's as an excessive accumulation of fouling on the bolt assembly. This fouling resulted in sluggish operation, which in turn, lead to failures to feed and eject. Frankford Arsenal was assigned the task of investigating the problem and determining to what extent the trouble was attributable to the ammunition used. In the course of the investigation, it was determined that these rifle lots which failed the endurance test were those firing Remington ammunition and using a Remington 721M Primer, which contains lead styphrate, barium nitrate, tetracene, antimony sulfide, and calcium silicide. Those rifle lots that passed the endurance test had fired ammunition using a Remington 92 Primer, which differed from the 72M Primer in that it did not contain antimony sulfide and calcium silicide.


In view of the possibility that the primer might have contributed to the excessive fouling problem, and until standardization of a primer-propellant combination could be accomplished, Frankford Arsenal recommended that a satisfactory discriminative fouling test be required as a criterion for 5.56mm cartridge acceptance. An approved change 3 5 / required that a 1,000-round fouling test be successfully conducted on each pre-production lot of ammunition and on any subsequent change in primer ingredients by the producer as a condition of acceptance. This change was incorporated into the technical data package for the fiscal year 1965 procurement program.

At the 3-4 June 1965 Technical Coordinating Committee Meeting, the Colt's Inc. representative reported that ammunition recently provided for the endurance test was causing more fouling than the ammunition previously used. The Project Manager directed Frankford Arsenal to conduct a primer chemical analysis to determine whether a producer had made an unauthorized change in primers.

Frankford Arsenal reported that its analysis had revealed no change in primer composition and that the primers were acceptable.

Further analysis of the chemical composition of primers by Frankford Arsenal resulted in a change in the military specification on 8 February 1966 to eliminate calcium silicide as an acceptable compound because it was a contributor to excessive fouling.

[Gary L. Griffiths]

was there any meaningful effect on group size or impact point of switching primer with no other changes?

Good question. Bearing in mind, I was using my AR-15 with premium Douglas stainless 16.5" barrel, with Primary Arms 1-6X tactical scope set on 6X at 50 yds, plus the fact that my eyes aren't as sharp as they usetawas, here's what I came up with:

Wolf Gold (which I had previously zeroed for: Vertical (V) 0.591 X Horizontal (H) 1.251 @ 0".

CCI-400 10-shot group: V 0.448 X H 0.628 @ -0.018"

CCI-41 10-shot group: V 0.488 X H 0.793 @ +0.050"

CCI-450 10-shot group: V 0.541 X H 0.711 @ -0.115"

The CCI-400 with Nosler 5-shot group: V 0.350 X H 0.304 @ +0.227"

The CCI-41 with Nosler 5-shot group: V 0.429 X H 0.445 @ +0.252"

The Carl Gustav LAP 10-shot group: V 1.620 X H 1.847 @ 0"

Bottom Line: CCI-400 (regular) primers gave the tightest groups (for me, at least), but only by about 0.1" @ 50 yds. I would have thought the CCI-450 with its more consistent velocity would have produced the tightest group; but then I would have thought it would have produced a significant increase in velocity over the 400, too. Go figure.

[Bart B.]

I think those groups are statistically and essentially the same size.

[pathdoc]

I think those groups are statistically and essentially the same size.

You can think that all you like, but a game animal's not going to wait around for the end of a five-shot string, let alone twenty or fifty or whatever it takes to satisfy you. For a hunter, it's the first three shots from a cold barrel that count. If the first five stay in that group, it's a bonus.

[arizona98tj]

Originally Posted by pathdoc

You can think that all you like....

Wow....what the heck kind of response to Bart B. was that?

[Slamfire]

I think those groups are statistically and essentially the same size.

I would agree. In fact, to determine if the loads are different, many more rounds would have to go down range. This year at the Small Bore Nationals at Wa Ke De Range, Bristol IN, Eley gave a presentation about ammunition testing. They use mean radius, which is without a doubt a better system, except for all the measuring and calculations. And, they showed 600 round groups out of two rifles, same ammunition, for comparison. And even then, there was only 3mm difference in extreme spreads at 100 meters between the rifles.

A shooting bud of mine asked Larry Moore about the number of rounds it took to have confidence in the accuracy of a load, and Larry said "about 20,000". At Aberdeen Test Range, Larry tested every potential US Army service rifle in the 50's, his reports still exist, and he was a competitive shooter.

Gunwriters have gotten extremely lazy, as loading and shooting takes time and effort, and I have noticed several big ones using the same sort of “hunters only shoot X rounds before the game is gone” as an excuse to limit their target groups to three shots. I have seen any number of articles in Handloader, Rifle, where the author is claiming sub MOA out of 30-30 Marlin Lever actions, cast bullets, and three shot groups. In actual fact, the first shot is the most important, but how do you know the six sigma limits of the population with only three data points?

[Gary L. Griffiths]

they showed 600 round groups out of two rifles, same ammunition, for comparison

A shooting bud of mine asked Larry Moore about the number of rounds it took to have confidence in the accuracy of a load, and Larry said "about 20,000".

I'll have to go to crowdfunding to buy components!

Valid points -- this is a small sample with only 1 powder charge measured. Still, one would expect the "hot" MilSpec and Magnum primers to raise velocity at least somewhat significantly. In any event, since I've still got 90 magnum primers, just for gits and shiggles, maybe I'll repeat the experiment with similar charges of AR-Comp, Varget, and BLC(2).

As for accuracy, yeah, they're basically a dead heat. I'm just pleased that I was able to get that degree of consistency out of my shaky old bod.

[Bart B.]

Here's a 270-shot group. Inner circle is 1 MOA, outer one is 2. Which set of five 3- or 5-shot groups do you think best represent the ammo's accuracy?

http://s735.photobucket.com/user/Bar...ml?sort=9&o=18

After you've picked yours, I'll pick five others for my test.

Then we'll make a composite of our 15- or 25-shot test to see which one's the best to represent the load's accuracy.

[Gary L. Griffiths]

Which set of five 3- or 5-shot groups do you think best represent the ammo's accuracy?

Not really sure I get your point. The size of the group is the size of the group. There is obviously no way to separate the group into 3, 5, or 10-shot groups.

If you're saying that measuring 3, 5, or 10-shot groups is not a valid way to assess a load's accuracy, I would disagree. I don't really need to run 20,000, 2,000, or even 200 rounds through a rifle to determine whether or not I can put it in an elk's vitals at 200 yds. Obviously, the more rounds you fire, the more statistical validity you have, but if you are testing three loadings, and one produces a 5" group, one produces a 3" group, and one produces a 1" group, I don't think that you would need to shoot 30 10-shot groups to determine that the 1" load is the one you want to refine and test further.

In any event, this thread is about the differences (or lack thereof) between CCI regular, MilSpec and magnum primers. Testing with three different powders will enlarge the dataset and perhaps show a greater variance with other powders. I'm not about to test ALL powders, or even a statistically significant number of them, but I thought it might be useful to have some additional data, especially if AR-Comp, by some fluke, is particularly easy to ignite so that it doesn't really matter what primer is selected in a .223 load.

From the results of my testing so far, I might postulate that the hotter MilSpec and magnum primers only make a significant difference in powders that are hard to ignite.

That leads to another thought: Small rifle primers are only really used in small-capacity cases, like the .222, .223, etc. With these smaller capacity cases, is there really any powder that is so difficult to ignite that it requires a magnum primer?

[T. O'Heir]

CCI "Milspec" primers are a brilliant marketing plan and nothing more. They're just magnum primers.
Slam fires are caused by improperly loaded ammo, not the primer itself or the rifle.

[mdmtj]

CCI "Milspec" primers are a brilliant marketing plan and nothing more. They're just magnum primers.

You base this statement on what?

[Bart B.]

That 270-shot group in the result of twenty-seven 10-shot, or fifty-four 5-shot or ninety 3-shot groups. They ranged from about .08 MOA to about 1.60 MOA. You cannot tell what the size nor center of either one is. All you know is the composite of all of them is over 1.6 MOA.

Would you celebrate if the first three 5-shot groups were under 1/3 MOA whether their centers were in the same spot or not? The first three or five shots are very poor indications of where the rest of them will go. All of those few-shot groups' centers will not be at the point of aim.

And small rifle primers have been used in some .308 Win cases for decades. I've had excellent results with Rem 7.5's in Remington cases.

http://riflemansjournal.blogspot.com...r-308.html?m=1

[Slamfire]

CCI "Milspec" primers are a brilliant marketing plan and nothing more. They're just magnum primers.

Slam fires are caused by improperly loaded ammo, not the primer itself or the rifle.

Here is your CCI hater. No logic, rationale, or supporting information behind his statement. Even the historical account of M16 slamfires, which caused a redesign of the weapon and the creation of "mil spec" small primers, does not change his pronouncements. AKA Sunray has been putting the same hate speech out there for years.

[Gary L. Griffiths]

Today I shot 90 rounds I loaded up with three different powders and the three different primers. They were all loaded in once-fired LC-13 cases with Winchester 55-gr FMJBT bullets. The loads consisted of 24.0 grs. AR-Comp, 26.4 grs. Varget and 27.4 grs. BLC(2); all of which should have given ~ 2850 fps. according to my calculations with QuickLoad. (I apparently need to upgrade my QuickLoad-fu.) I "warmed up" by firing 10 rounds of Wolf Gold factory loads, with the following results:

Wolf Gold: Avg 3046.60 fps., SD 26.65, Gp Size 0.71" @ -1.13"

CCI-400 w/ AR-Comp: Avg 2945.90 fps., SD 14.42, Gp Size 0.94" @ -1.10"

CCI-41 w/ AR-Comp: Avg 2949.30 fps., SD 15.55, Gp Size 0.88" @ -0.98"

CCI-450 w/ AR-Comp: Avg 2939.80 fps., SD 17.13, Gp Size 1.32" @ -0.82"

CCI-400 w/ Varget: Avg 2940.80 fps., SD 33.72, Gp Size 1.21" @ -0.75"

CCI-41 w/ Varget: Avg 2950.60 fps., SD 20.37, Gp Size 0.96" @ -0.76"

CCI-450 w/ Varget: Avg 2894.20 fps., SD 32.49, Gp Size 1.11" @ -0.83"

CCI-400 w/BLC(2): Avg 2890.70 fps., SD 19.79, Gp Size 1.78 @ -0.85"

CCI-41 w/BLC(2): Avg 2860.30 fps., SD 34.70, Gp Size 1.01" @ -1.11"

CCI-450 w/BLC(2): Avg 2906.30 fps., SD 29.38, Gp Size 1.10" @ -1.81"

Although this test certainly wasn't exhaustive, the bottom line seems to be that there is negligible, if any, difference between the three types of primer. For my part, I'll be loading with CCI-400s from now on.

The only reason I can see to buy 41s or 450s would be for an arguably greater protection against slam-fires. Some believe this protection is necessary, while others warn that the tougher MilSpec primers may cause FTFs. I've loaded and fired close to 4,000 rounds of .223 through one or another of my 3 AR-15s with CCI-400 primers, and never had a slam-fire. I've loaded and fired approximately 400 rounds with CCI-41 primers, and have never had a FTF of any sort.

FWIW.

[tangolima]

Slam fire did happen to me with wlr primer, and it was corrected by switching to tula NATO primers. The rifle was m1 garand.

-TL

[4runnerman]

I also have done same test with 400,450's and BR-4's in 223 bolt. I did find FPS difference,but not that much. The main thing I noticed was accuracy and consistancy in accuracy. I now only use BR-4 primers.

[4runnerman]

CCI "Milspec" primers are a brilliant marketing plan and nothing more. They're just magnum primers.
Slam fires are caused by improperly loaded ammo, not the primer itself or the rifle.
__________________
Spelling and grammar count!

Umm ahhh Ok. now that is the most off the wall comment I have ever heard. No correlation between that statement and real slam fires

[pathdoc]

There are days I'd be more than happy to fire 20 shot groups of every load I try, if only for the challenge and practice that comes with every shot; and I'd love to wait the three or four minutes needed to let the rifle cool down completely between shots, but let's face it - for quite a lot of people, their TIME, their MONEY and their COMPONENT AVAILABILITY are all at a premium.

The best is quite often the enemy of the good enough, especially at the moment. Show me the Golden Age in which eight-pound containers of Varget and IMR3031, scores of different bullet types in .224" and .311-312" and more primers than I can safely or easily store are readily available at dirt cheap prices any time I walk into my LGS, and I'll show you an Age in which I will play the game Bart B's way. Until then, economy is the name of the game.

[Bart B.]

There was a fella who tested his hunting reload recipies with two shots. His reasoning was rather simple. Half way between the two shot holes was the group center. The extreme spread was easily measured. 'Twas good enough for his hunting.

He blamed all the biggest groups on his own skills. And believed no rifle made in the USA using reloads with USA components would ever shoot more than one MOA at a hundred yards.