223 Flat Primers

[Pbaker]

Not sure if this is the right forum for this, and I've read varying posts about flat primers related to over pressure, but...

I've been loading what I think are light loads for my 223 Wylde (Berry's 55 gr FMJBT on top of 24 gr H335, CCI 400's). I've been averaging 2850fps, but I have flattened primers. Not horribly flattened, but definitely not rounded. Question is, are the loads too light to form the brass, causing the primers to take the brunt of the pressure? Or do I have loose primer pockets (mixed brass that's been trimmed and swagged). Or something else???

I don't think that I have anything close to over pressure, but I figured I would get a second (or 20) opinion.

[trails4u]

Pictures would be very useful...… Underpower loads can also 'show' signs of primer problems interpreted as overpressure, but at 2,850fps, I'd be surprised if that's the case.

[Pbaker]

256983

[Pbaker]

256984

[Winger Ed.]

They look OK to me.
In the scheme of things, you're in the Goldilocks zone and about where ya want to be.
I load 24-25gr of 748, as a mid pressure load for GI pulls of 55gr., and the middle one is about what mine look like.
I also use just regular SR primers from CCI or Winchester.

The case on the right is a true flattened primer.

[Pbaker]

Last one

256987

[Pbaker]

I figured it wasn't a big issue, but with being on the lower end of pressure/velocity, I found it odd that I have this going on. I want to increase the load, but I have reservations.

[Winger Ed.]

You're good.

I tend to stay around 80-90% of a full house load (developed for best accuracy) for most of my shooting.
It works, and keeps some of the stress off the weapon.

High pressure stuff is like driving your car at 130mph.
It'll do it, but it'll also last longer if ya stay under about 80.

[Hossfly]

Be sure your cases are clean and dry also so when the round fires the case grabs on and bolt face and primer doesn’t take all the pressure. I’ve forgotten several times to clean the lube off and had similar problems.

[RickinTN]

Your primers look about like what I get when I'm loading medium loads, which is about where I usually hang out. Without checking data I think your are a medium load. I see no issue with them. The picture on the right in post #5 is a flattened primer. It is good to be cautious.
Best,
Rick

[tomme boy]

You can go ALOT higher than that load for 556 pressures. Do a little searching and you can find the data you need. Those look fine as they are. You should find a node with just a little more. 55gr vmax seemed to be 24.3-24.5 in the 5 different 223 rifles I have.

[Norske]

If you are over-sizing your cases so they feed easily, they could be pushing forward when the firing pin hits, allowing the primer to back out slightly, then get flattened when the full powder charge ignites. It's one reason primer appearance isn't reliable. There's also an advantage to bolt action rifles, as the cases can be sized for a slight crush fit.

[dkf]

In my ARs I don't really worry about primer flatness with .223 pressure loads because I'll usually end up with some pierced primers and "dimples" in the center of the crater when the pressure gets up there.(CCI 400) Then I usually switch to CCI SRP BR primers and use them all the way up to max 5.56 pressures. Have not had any BR primers (or military primers to pierce. Usually they just start to blow out the case when pressures get up there, as I do not have the capability to crimp the primers in place.

[McFred]

Pbaker, I agree that the photos you posted those primers are not very high pressure. However, I would not explore "max" pressures with mixed headstamped brass. .223 case capacities vary a lot, and what may be fine for a lighter case may be over pressure in a heavy case.

[lotech]

I like the CCI400 in .223 / 5.56 as I've usually seen slightly better accuracy with it over other primers, but the cup is softer and it will definitely "flatten" more quickly than the harder CCI450 or Remington 7 1/2. I'm unfamiliar with your load, but it might pay to experiment with other primers.

[Norske]

If you try other primers, be aware the power varies by brand. For example, Winchester primers are designed to reliably ignite graphite coated double-base powders. My Western Powders reloading manual lists only Winchester (rifle) and Federal (handgun) primers in their load data.

[Geezer in NH]

Those are not what I call a flattened primer, all the edges are rounded. Flattened will be FLAT all the way across the pocket.

[Norske]

Hard mil-spec primers can be found. Sorry, I don't know the brand for sure (CCI?) or the number.

[Dapaki]

I too have wondered about .223 pressures and flattened primers using CCI 400's. Like Norske says, try the CCI Small Rifle Military Primers #41, or similar, you will see "normal" pressure marks on them instead of flattened primers with the same pressures.

[HangFireW8]

Those primers are fine. Pay attention to what hossfly says about chamber stiction.

[tomme boy]

CCI SR primers are not meant to be used in 223 or 556 loads as they are meant for the 22 Hornet class of cases. Otherwise 46K psi max. That is why they flatten and pierce. They are thinner than all other primers. Use Win SR and don't worry about any of this.

[GONRA]

GONRA (as mentioned by others above) suggests CCI Military primers (small rifle and large rifle) for all semiautos.

[pacomdiver]

i load 26g H335, 55fmjbt (both new and gi pulls) and cci primers at 2.245 OAL in mixed brass, for all of mine, my sons 2 and 2 buddys ARs. with the eotech on my 16" olympic, i can hit the 4" steel plate at 100 all day long offhand, the dot almost covers the whole plate