Confused about CCI400 vs CCI450

[wallaceg]

OK, just about everything I have read is that you must use CCI450 primers for this cartridge. So, I paid a lot of money to buy 1000 primers online. When they came, I immediately started testing. I had a previous AR15 of this caliber so I proceeded with old loadings that had worked well with it. I have a 20" Lilja 1-8 twist barrel. I had always used CCI400 primers in the past so I slowly worded up some loads with powders I had used before. These included Benchmark, RL15, CFE223, BL-C(2), TAC, VV N133, and XBR8208. In every case, velocity was less with CCI450 than with CCI400. Accuracy was marginal. I started loading 5 rounds with 400 and 5 rounds with 450 using my best-performing powders which were 1. Benchmark, 2. RL15. Benchmark being the fasted and RL15 the slowest of the powders I used. In EVERY case, the velocity was slower with 450 and the accuracy was better with 400. The velocity was only about -10fps slower but I would have expected it to be faster since most magnum primers add about 60psi. Apparently, the only difference between CCI400 and CCI450 is the dimensions of the primer cup. The differences are: 400/450, Cup thickness .020/.025 Cup Diameter .1753/.1750 Cup Height .109/113. I guess they call the 450 a Magnum only because it may be able to stand up to chamber pressure higher than the 400. The peak pressure for this cartridge is 50,000. In all the MAX loads I have used, none have shown any sign of overpressure using either primer. In "most" instances, 50,000 psi is not in the magnum category and would not necessitate the use of 450 primers in the 6.5 Grendel. One other clue is the primers look identical. Both have an identical yellow cup. This would tell me that there is no liability issue if you were to mistake one for the other. Apparently, Bill Alexander used CCI450 primers in the development and it just stuck. All of the Alexander Arms reloading information I have found always lists the primer as CCI450. Other manufacturers use different primers such as WSR. Just my thoughts!

[Harpoon1]

[grayfox]

No you did not read that. Nowhere has this forum said that "you must use cci450 primers" for this cartridge." Let's get that settled right now.
There is a lot of advice/opinions on which primers are better, or worse, for not only AR but also for a bolt action. You pays your money and you makes your own choices. With powders, brass, primers, bullet, rifle model, even reloading protocols. It is ALL under your own direction. And I believe if you are honest that is the tenor of the advice on here.

As to primers: The brisance of the 2 versions, 400 v 450, is different, as are the physical dimensions (several posts on this). That is the heat or flame ability. Each of the different primer versions, Mfr X vs Mfr Y, regulars and magnums, has a different brisance. Read about the tests online. CCI, Federal, Remmy, Winchester, Wolf, Mil-std, they are all different in their specific heat/flame.

No one, that I recall, is saying that you "must" use one primer or not, all of these are simply recommendations and you are in control of your own loading.
The 400 has a thinner cup and is more liable to a pierced primer or possible slam fire than the magnum, or than the #41 (for small rifle primers).
If you simply substitute a different primer for your "normal" primer/load combo, then for sure the MV will differ, and may or may not be more accurate, or even more or less scattered- SD-wise for MV. Same is true for substituting one brass for another. Or one lot of powder for another. Raw substitutions without proper workup - any bad impacts are on you because you did not start low and work up.
Now I personally have not had any slamfires nor any pierced primers from AR shooting but then again I do not shoot 1000's of rounds a year.
Others whom I respect have had the same.
You get to make your own choices.

[lazyengineer]

Thanks for the post - always good to get more info as I try to learn as much as I can about this cartridge. You mention that the velocity is lower in comparison, but may I ask, were these side-by-side comparisons fired on the same day? Or is this in comparison to prior records? I ask, because most people don't really account for barrels slowing down as they age. I suspect it's the lengthening throat letting more gas leaks by, or the bore gets more loose. But in any event, it is known that barrels slow down as they age. Other possible factors include powder aging, if this is the very same jugs, and they are getting older. It won't really go bad or weaker with age, so much as it can accumulate humidity over time, even through the plastic. Not sure your situation, storage practices, etc, but gunpowder mass can change up into the full digit percentage point, depending on their humidity exposure over time. Someone who scientifically tested this, found as much as 3-digit velocity change, just based on the humidity of his powder exposure. Also, in my experience, the Chorny being used can matter as well, and I tend to find the precision of a chronograph can be good on any given day, but it's actually accuracy can move around by well over 10 fps, (or so I suspect).

Just trying to point out some items to ponder, as 10 fps isn't that much of a velocity difference.

As to primer impact on round performance - to be honest, with 6.5Grendel, I don't think it matters that much. Over the years, I did test and find with a really slow blue-dot powder in 9mm, magnum primers gave a measurable change in velocity. But that was a really slow pistol powder that's difficult to ignite and leaves lots of unburned powder when used; primer hotness mattered. Rifle is another matter. I personally haven't noticed much difference when switching primers at all in Grendel, to be honest, aside from a couple learning experiences I'll note below.

As to primer choice, I like CCI450 in the 5.56 AR15 as a general purpose primer, but have run pretty much everything under the sun. The only time I had issue was running surplus H335 at below-minimum load in 5.56 (trying to be "safer" doing a test on something), using weak CCI400 primers. With that much void space with a difficult to ignite ball powder - those rounds would hang-fire. That's where I learned void space matters. I repeated that experience running faster 4064 in 6.5CM in small primer brass. This had a decent amount of void space. CCI450 would 1/4 second hangfire almost every single shot - cost me a deer-neck shot ending up being a gut-shot - that sucked (yea yea, "it wasn't my fault"; but I made the ammo, so still my fault). CCI41 would fire per normal. There are Johnny's youtube video's on this very topic (that I discovered AFTER). Void space in a casing matters a lot, and frankly, I consider that a factor on my primer selection first - as only use your hottest primer, if it has a lot of void.

But 6.5 Grendel does not have hardly any void. It's a small case, and in the end, it's the gun-powder that makes it go. Point being, no, I personally don't have issue with CCI400 in 6.5 Grendel, and would run it if I had it. It's a low pressure round, with low void-space, and usually fed with faster powders that are happy to ignite, like 8208. I've never had a slam fire with a CCI400, or know anyone who has.

As to your slower velocity difference, my own suspicion is it's either a more worn barrel when tested, or other system experimental error (such as the calibration scale being .1 gr off, or sizing neck tension of this brass was different, or the chrony was mounted just a time bit different), than actually due to the 450 sending a weaker shot than a 400.

Who knows, I look forward to the replies from others, who maybe have also observed similar as yourself?

[Happy2Shoot]

My experiment with .223 Rem


CCI #400
2861
2871
2872
2875
2873

Average 2870
SD 5
ES 14



CCI #450
2947
2925
2925
2933
2936

Average 2933
SD 8
ES 22

[Klem]

Wall,

I wouldn't expect to see much difference across same type of primer, from the same manufacturer. Between 400/450 the pyrotechnic disk might even be the same and it's only a difference in cup shape and thickness, Plus, as Lazy says there are a lot of other variables that could account for any difference when testing 400 and 450's.

I did a velocity test in subsonic Blackout between CCI450's and their 500 small pistol primers. Same day, powder, bullet, labradar etc - 20rds of each. CCI450 (Rifle Magnum) was 1,028fps and CCI500 (Pistol) was 1,010fps. Only 18fps difference across two types of primer; Rifle and Pistol.

The 450's are favored by the F-Class guys due their thicker cups to prevent piercing in hot 1,000yd loads. By the same token we use them to mitigate slam fires (not that I have ever seen a slam fire in my life - other than in books and online).

If you did that test on two separate days then to be fair any MV difference observed will be caused by a multitude of variables. Even on the same day with the same primer it is likely your MV between strings will be different. The difference between primer types is small enough, and the similarity of velocities using the same primer large enough that your claim to reliability is unreasonable. What I am more concerned about is not so much trying to predict the velocity to a single fps but the consistency of velocities. So, the standard deviation of the strings. In the Rifle/Pistol primer experiment the 450's were more consistent (lower SD). In rifle shooting 450's permit single digit SD's in really careful loading, and that is good enough for me.

Talking about statistics, the number of shots tested makes a big difference when claiming one type is different from another. If you only shoot a handful of rounds then your confidence level should be low.

[CavityBackBullets]

CCI400 and CCI450 primers have a different brilliance. This is why the CCI450 is listed as a magnum primer.
Also why the CCI450 or CCI41 (also magnum brilliance) are recommended for ball powders, or any magnum primer for ball powders in cold weather.
Ball powders have a coating that makes it harder to light.
Physically the CCI450 has a .025 thick cup thickness, while the CCI400 has a .020 cup thickness.
So the CCI450 is hotter than a CCI400 and has a thicker cup.
The CCI41 also has a .025 cup thickness but also has an anvil designed to help prevent slam fires.
Other primers that have a .025 cup thickness are CCI BR4, Rem 7.5, Fed GM205MAR (also a magnum primer with a anti slam fire anvil).
Wolf magnum primers and S&B small rifle primers are also a .025 cup thickness if you can find them.
Wolf primers are pretty hot, while the S&B small rifle are like halfway between a CCI400 and CCI450 in brilliance.

YMMV

[Dt219]

[wallaceg]

After a lot of internet searching, I found this great article that pretty much answers all my questions about primers. Small Rifle Primer Performance by Laurie Holland. There are 3 parts and Part 3 was the most interesting to me. Well worth the read.

[jasper2408]

After a lot of internet searching, I found this great article that pretty much answers all my questions about primers. Small Rifle Primer Performance by Laurie Holland. There are 3 parts and Part 3 was the most interesting to me. Well worth the read.

Getting "Error establishing a database connection" when I try your link.

[wallaceg]

No you did not read that. Nowhere has this forum said that "you must use cci450 primers" for this cartridge." Let's get that settled right now.
There is a lot of advice/opinions on which primers are better, or worse, for not only AR but also for a bolt action. You pays your money and you makes your own choices. With powders, brass, primers, bullet, rifle model, even reloading protocols. It is ALL under your own direction. And I believe if you are honest that is the tenor of the advice on here.

As to primers: The brisance of the 2 versions, 400 v 450, is different, as are the physical dimensions (several posts on this). That is the heat or flame ability. Each of the different primer versions, Mfr X vs Mfr Y, regulars and magnums, has a different brisance. Read about the tests online. CCI, Federal, Remmy, Winchester, Wolf, Mil-std, they are all different in their specific heat/flame.

No one, that I recall, is saying that you "must" use one primer or not, all of these are simply recommendations and you are in control of your own loading.
The 400 has a thinner cup and is more liable to a pierced primer or possible slam fire than the magnum, or than the #41 (for small rifle primers).
If you simply substitute a different primer for your "normal" primer/load combo, then for sure the MV will differ, and may or may not be more accurate, or even more or less scattered- SD-wise for MV. Same is true for substituting one brass for another. Or one lot of powder for another. Raw substitutions without proper workup - any bad impacts are on you because you did not start low and work up.
Now I personally have not had any slamfires nor any pierced primers from AR shooting but then again I do not shoot 1000's of rounds a year.
Others whom I respect have had the same.
You get to make your own choices.

First, I did not say anywhere that anyone in this forum said you must use CCI 450 primers. Second, you say the brisance is different between 400 and 450. Show me a chart that lists the brisance of any of the primers. I cannot find one. Please tell me your source. Third, in my post, I actually listed the physical dimensions of the primers in question. Fourth, I did mention that I slowly worked up new loads from old loads I had used before. I have been reloading for over 50 years. I wasn't asking how to work up loads. I fired over 300 rounds over three days using 9 powders, 5 bullets, 3 cases, and 5 different primers to get the results I posted about. It's as if you did not read my post at all. If you don't have anything positive or helpful to say like the other replies, just keep it to yourself.

[wallaceg]

Getting "Error establishing a database connection" when I try your link.

Here is the direct link. http://www.targetshooter.co.uk/?p=2662

[jasper2408]

Here is the direct link. http://www.targetshooter.co.uk/?p=2662

Sorry it turns out it was my browser. I use some extra security extensions to keep the boogeyman out and they were what was blocking it. Opened OK in MS Edge. Thanks.

[wallaceg]

Sorry it turns out it was my browser. I use some extra security extensions to keep the boogeyman out and they were what was blocking it. Opened OK in MS Edge. Thanks.

By the way, part 1 and 2 are also very informative.

[jasper2408]

By the way, part 1 and 2 are also very informative.

Ok thanks for the info.