Just wondering you guys thought, Primer pics.

[223to45]

Ok, I am a little new at looking for signs. I hear about flatten primers offen, but never really knew what to look for.

After my range trip, I noticed some seem pretty flat. In the first pic the two cases lost there primers, came out after ejection, cause I find the primer, the other was about 3/4 of the way out, I pushed back in with no real effort. I am assuming maybe the primer pocket is not good.

So what do you guys think??. Some seem ok, but others I am not sure about.

As far as load data, I am right in the middle. On all the powders, I took the min and max, and split it. So they are all loaded right in the middle.



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[Uni-Vibe]

You should never, never be blowing primers out of primer pockets. That's a very bad sign.

I'd check headspace on the rifle. If that's in spec, then there's some problem with the ammo. That very lowest cartridge in the last photo? Primer looks mighty flat. If the rifle is in spec, pressure is too high.


Are you using a chronograph? Watch for excessive velocities which signal excessive pressures.

[223to45]

You should never, never be blowing primers out of primer pockets. That's a very bad sign.

I'd check headspace on the rifle. If that's in spec, then there's some problem with the ammo. That very lowest cartridge in the last photo? Primer looks mighty flat. If the rifle is in spec, pressure is too high.


Are you using a chronograph? Watch for excessive velocities which signal excessive pressures.

Wasn't using a chrono yet. That was the next step.

I will double check headspace.

One thing I did noticed before I reloaded those, some of the factory stuff seemed a little flat too.

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[Kansaswoodguy]

what barrel/chamber does your gun have and what was your load recipe. They look over presser to me might check your loading scale zero against a bullet of known weight if you don't have the little scale calibration weights. I always take a flashlight and look down into all my cases following powder charging to make sure I didn't make a mistake or had powder bridging in my powder throw causing low powder in one case and extra powder in the next. All your cases look bad so I'd say it wasn't a single over pressure round something with the recipe bullet weight/powder combination maybe seating depth or crimping the heck out of the necks. Idk proceed with caution!!!

[Kansaswoodguy]

And you have different head stamped brass your shooting yourself in the foot mixing brass if your interested in accuracy.

[223to45]

what barrel/chamber does your gun have and what was your load recipe. They look over presser to me might check your loading scale zero against a bullet of known weight if you don't have the little scale calibration weights. I always take a flashlight and look down into all my cases following powder charging to make sure I didn't make a mistake or had powder bridging in my powder throw causing low powder in one case and extra powder in the next. All your cases look bad so I'd say it wasn't a single over pressure round something with the recipe bullet weight/powder combination maybe seating depth or crimping the heck out of the necks. Idk proceed with caution!!!

8.5" 300blk , Ballistic Advantage barrel and BCG.

Load data I will have to look up when I am home. But I went right in the middle of min and max on all powders.
They types of powders are written on the plastic bags.
CFE Black, Win 296, Lil Gun, Accurate 1680

Using Lyman 50th, Accurate powder, and Hornady 10th.

150 gr Sierra FMJBT

Now crimping is not something I thought of, I will double check my adjustment.

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[cutter_spc]

Ah the 300 BLK...... the most finicky round I run across to date, and that's saying something, I've been loading for 30 years.

First. Yes, blown primers are a major warning sign. You should have been seeing ejector smear before that, but you stared out with "middle of the road load data", we all do it and sometimes it bites us.

Second. Your using mixed brass, which means your case capacity is varying, not to mention neck thickness. The BLK is very, and I mean very sensitive with it's capacity, just simply changing bullet brands in the same weight category is enough to throw things off sometimes. There are some brands of brass out there that when converted to BLK the neck wall are too thick and cause excessive pressures.

Third. And I know people are going to argue with me on this, but it doesn't make it any less true. Annealing. If the cases haven't been properly annealed after forming to BLK the neck and shoulder area COULD be too hard messing with the springieness the round needs to survive the relatively violent loading in the AR. If neck tension isn't enough the bullets can be set back during chambering and the same thing with the shoulder, see the Second above. You can test for this by making dummy rounds and letting them load from a mag by letting the bolt fly home from bolt lock. Use calipers to measure before and after OAL, and a case cage to test shoulder set back.

Backoff to starting loads, sort your brass, and work up in .1-.2 increments. Be safe.

[223to45]

This is the one that the primer was partly push out , I gently pushed in at the range.
I took a paper clip with also most no pressure push out primer.

Accurate 1680 20.6 gr ( Western Powder data)
Win 296 15.4 gr (Sierra data)
CFE BLK 18.7 gr ( Sierra data)
Lil Gun 14.4 gr ( Hornady data)

All loaded to 2.140"

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[gaijin]

Sort your brass by headstamp.
Individually weigh each powder charge. I would focus on TWO powders; 'lil Gun and 296, which have long track records in 300 Blk.
Start closer to bottom of listed charge weights, load 5 or 10 rds., increase by 3/10th's to close to max. Use a chrono.

Load data that "works" in LC (as example) may/will not necessarily work in Barnes brass (as example).
Converted 5.56 to 300 Blk may have less internal case volume/capacity than purpose designed 300 Blk.
The powders you're using are effectively slow, pistol powders- which are fast rifle powders. They will be much less forgiving in minor variations of powder weight/bullet seat depth/etc. than say a .308.
It appears you are heading in too many directions at once- with multiple cases/powders, to begin to narrow down the apparent over pressure issue.

[AndyLate]

Both rounds in the first pic show obvious over pressure signs. One case has most of the head stamp ironed out and the second has flowed brass into the ejector hole.

Start at the minimum load and work your way up.

Andy

P.S. I don't reload 300 BO, but do reload a good bit of 5.56/.223 and other calibers.