No 41 primers

[akinswi]

Just ordered some CCI No 41 primers off Midway (yeah they actually had primers in stock) to load some .223 and 556 for my Armalite M15A2 HBAR

any load difference between the 400s? or the BR4s? are these hotter or just harder primer cup to reduce slamfires

thanks

Powders I will be using WC846, WC844 , H335, IMR4895

.223 Cases will be once fired PMC Bronze
556 Cases will be once fired PPU M193 brass

[ligonierbill]

CCI #41 is equivalent to their 450.

[74A95]

Technical information about a product should be directed to the manufacturer.

A forum is not a good source for factual information.

[kilotanker22]

Originally Posted by 74A95

Technical information about a product should be directed to the manufacturer.

A forum is not a good source for factual information.

However true that may be, post #2 is correct with one caveat. The primers are meant to be less sensitive to prevent slam fires in automatic weapons, (I believe).

I use them in my 5.56x45 NATO and my 6.5 Creedmoor. They are excellent primers. Wish I could find a brick of CCI #34 though

[akinswi]

@ Kilo,

Hope you find some I have been looking for over a year for #34s for my M1
no luck

[Shadow9mm]

I called cci and asked this same question several months back. The answer was, it is identical to the cci #450 small rifle magnum in all areas except 1. They changed the anvil angle to make it less sensitive to prevent slam fires in ar's.

[akinswi]

Shadow,

That’s another interesting fact I was wondering Are slam fires even a worry in a semi auto AR 15? I can understand full auto M4s and Maybe M249

[stagpanther]

That’s another interesting fact I was wondering Are slam fires even a worry in a semi auto AR 15? I can understand full auto M4s and Maybe M249 and Mini 14

The AR's firing pin is "free-floated." Compressed crud inside the bolt can change the pin's clearance.

[Shadow9mm]

Originally Posted by akinswi

Shadow,

That’s another interesting fact I was wondering Are slam fires even a worry in a semi auto AR 15? I can understand full auto M4s and Maybe M249

The reason I called cci was because a bunch of people told me it was not safe to use regular small rifle primers in the ar platform. I called cci. They said they recommend a 450 or #41 to prevent slam fires. They also said some people use standard small rifle primers without issue. They said, at the range while pointed down range, drop the bolt and chamber a round. Check the primer. If there is any significant marks from the primer there is a risk of slam fires. For me I has just the slightest dot. I have been using them for a while with no issue. With that said I have switched to 450s or #41 per their recommendation.

[akinswi]

Thats interesting, Seating depth of the primer is crucial too.

[totaldla]

Originally Posted by stagpanther

The AR's firing pin is "free-floated." Compressed crud inside the bolt can change the pin's clearance.

Interesting theory. Please point me to your source as I cannot find any information on the compressed crud theory.

[Unclenick]

If you read through this fairly thorough discussion based mainly on congressional hearings about failures in the XM16E1 in combat, you learn several key things. One is that the original firing pins were heavier and therefore more prone to slamfire than current firing pins. Another is they had some improperly specified primers in the 1960s and that with properly specified ones, even the heavy firing pins were much less prone to slamfire. Finally, they had a positively criminal problem with mis-specified powder that resulted, among other things, in a 200 Round per minute full auto rate of fire increase that slammed the BCG's both rearward and forward harder than current AR's and military BCGs run, and that increased the momentum in the firing pin. With those things fixed, current versions are not so prone to slamfires.

The thing to keep in mind, though, is that less sensitive primers are part of the combination of changes that solved reliability problems.

The final military primer sensitivity specification is matched by the sensitivity of both the CCI #41 and the Federal GM205MAR primers. The order of increasing sensitivity of the CCI primers is CCI #41, #450, and #400. The #450 is more sensitive than the #41 because of the different anvil (information from a past phone call I had with them, as well). The wider spread angle of the anvil's tripod legs makes it shorter and less rigid in opposing the firing pin blow. It also makes the finished primer on the shorter side overall, so it has to be seated a little further below flush with the case head to achieve optimal reconsolidation (bridge set), which also reduces the indentation made by the firing pin's inertia when the bolt closes (high primers contribute to slamfires). The #400 is more sensitive than the #450 because, according to James Calhoun, its cup floor is 20% thinner than the #450 cup floor (but that is 1995 information, so it would have to be confirmed by the manufacturer to be sure it is still so).

I don't have a confirmed sensitivity order for Federal primers, but I do have an email from Federal stating the GM205MAR, as compared to the GM205M match small rifle standard primer, uses a thicker cup as its means of reducing sensitivity to the military spec level.

I don't know the practical concern with slamfires in the AR after the firing pin and powder issues are addressed. I don't recall hearing them happen when the command to load is given on the firing line at matches the way the Garands used to have periodically. I know the late Glen Zediker, back when you could get them, said he would buy new primed Winchester brass and use it for first loads without modification, and Winchester SR primers have none of the special sensitivity reducing steps taken on them. But Zediker would have used a gun properly in spec, and with all the DIY builds and brand variations around these days, I am less sanguine that all guns would be equally slamfire resistant when using them.

[stagpanther]

Interesting theory. Please point me to your source as I cannot find any information on the compressed crud theory.

Based on my personal experience theory. Doesn't bother me in the least if you call bunk. fire a few hundred cartridges without cleaning and then pull the firing pin--what do you see in front and aft of the stopper ring on the pin? what do you see inside the carrier where the bolt is retained?

[ciwsguy]

Originally Posted by akinswi

@ Kilo,

Hope you find some I have been looking for over a year for #34s for my M1
no luck

I have a brick of #34s that I offered to trade for a brick of Large Pistol or would sell it for the $80 I have in it. I texted to your cell number per your request, but you never replied.

[603Country]

This was a very informative primer discussion.

[akinswi]

ciwsguy,

I sent you a PM , provided more contact info. sorry if there was mix up

Thanks

[ciwsguy]

Received and replied to both text and email

[totaldla]

Originally Posted by stagpanther

Based on my personal experience theory. Doesn't bother me in the least if you call bunk. fire a few hundred cartridges without cleaning and then pull the firing pin--what do you see in front and aft of the stopper ring on the pin? what do you see inside the carrier where the bolt is retained?

I spent considerable time researching slam fires in ARs and found nothing. I'm very aware of how the firing pin works in an AR which is why I wanted more info on your compressed crud theory.

A spec AR bolt carrier group will dimple a primer but no more. It will dimple a hard CCI41 the same as a soft CCI400. I know as I've tested it.

[berettaprofessor]

Keep checking back. I also used to use CCI400's exclusively until they were unavailable (and no slam-fires with them), but I just bought CCI41's from Midway too. I've got 10 rounds loaded with 400's and 10 with 41's that I'm going to chrony later today and I'll report here.

[berettaprofessor]

Okay, so I ran 10 each of 223 loaded with either CCI400 or CCI41.

And essentially the two are the same velocity, with more standard deviation of the CCI41 rounds. If the CCI41 is more of a magnum primer, I can't tell it from the chrony.

See the attachment for a chart.

Explanation: The first two columns are 10 shots each of CCI400 or CCI41 done today. The third column are three shots today to check my scope and the chrony with previously loaded CCI400 rounds. All these were shot out of a Stag AR with a 24" stainless bull barrel, 1:8 twist. The twenty test rounds and the previously loaded rounds were loads of 24.0 grains of CFE223 (dropped from an RCBS Lite Chargemaster) behind a 62 grain Hornady Match bullet. The 4th column is my previous test of those rounds (9 shots, but through a Savage Axis and in cooler weather). Today's temps were 79F, 50% humidity, light gusts.

The upshot, is that I couldn't tell the difference between the primers, either by velocity or by the case appearance (flat primers, but no other marks on the case). The CCI41's had greater deviation but I saw that much deviation in a previous identical load of the CCI400's when I initially tested it.

I would say that the CCI400 rounds today had slightly smaller group sizes (3 groups of 3 rounds each) than the CCI41, but that could be entirely a function of the standard deviations of those groups and the rifle. This rifle really doesn't like the 62 grain match Hornady's; it's a laser with 52 grain ELD's, but not for these. I only used them for the test because I had a bunch to use up.

[akinswi]

berettaprofessor,

Interesting results, usually with magnum primers you get better ignition which should typically result in lower SD. So maybe they are not reacting like magnums? I wish you could test the 450s. compare the results.

The Load you used was it originally worked with the CCI 400s?

I usually work up a load with different primers because I have found that I dont always get the same barrel harmonics with same powder charge and different primers.

[Shadow9mm]

That's odd. I got much better SD and es with cfe223 when I switched to magnum primers

[Unclenick]

It depends on the powder and how easily it lights up and sustains pressure, how large or small its bulk density is (how much empty air space it has), and also on how fast it lights up. Either can be the one that does better depending on these circumstances.

The size of the dimple made in a primer doesn't tell you how much energy was transferred to the priming mix because it doesn't account for how rigid the support from the anvil is behind the priming mix, which is what CCI found makes the sensitivity difference.

The only way I know to reliably test primer sensitivity is with the formal setup. This has primers in a fixture that acts as a primer pocket with the open end pointed to the ceiling. A primer is placed anvil-down into it and a floating firing pin is set on top of the primer. A standard weight ball held above it by an electromagnet is released from a calibrated height to fall squarely onto the firing pin. The weight of the ball times the height of the drop determines the number of inch-lbs of energy in the impact on the firing pin. This is called a height test or h-test. Below is a military spec.

[berettaprofessor]

The Load you used was it originally worked with the CCI 400s?

Yes, but I wouldn't really stand by it as a "worked up" load. It was a decent velocity node but never panned out to be a sub-moa load with that rifle....better with the Savage axis. The Stag AR liked the 52 grain ELD's.

[armoredman]

Ah, YOU'RE the reason they were out of stock when I got my notification! Just kidding.