Flat primer concerns ... did I ruin my brass?

[Tikka223]

I'm going to post this here because it was done in the course of "precision shooting";

Today I shot at a "Tactical / Pecision" match and it was HOT, around 30-35'C hot.

My usual load of preference in my .223 Rem T3 action is 24.4gr of Varget, CCI Br4s, Winchester brass and Berger 80gr VLDs. I've fired probably 300-400 rounds of this load all with the same brass. I have been running the brass through a Lee Collet neck sizing die. During my last outing I notice that the bolt was stiff after firing a few rounds but there was no flat primer problem. I went home and ran the brass though a Redding full length sizing die and reloaded the ammo with the same load.

Today, after shooting (my bad) is when I noticed that the primers on all my fired brass are very flat. During shooting I never notice any sticking bolt problems. So ...

a) did I resize my brass too short and thus greatly increase pressure?
B) did the high tempreature today increase the pressure enough to cause flat primers (I don't think I've been shooting this load in tempreartures over 25'C?

And most importantly, IS THIS DANGEROUS??? If its not the end of the world I will fire off the remaing 14 rounds on a cooler day.

Or, can I load up what's left of these full length sized cases and keep shooting the same load to fireform them again? Other wise, I may buy a new batch of brass.

Thoughts???

 

[Tikka223]

The ammo still shot accurately although I suspect the velocity has changed because the adjustments I have been using from iSnipe are no longer that accurate, I needed to adjust higher each time. This too is a first since resizing the brass. Or could the high humidity account for this?

 

[CyaN1de]

Pop the primers out and put new ones in. If they go in very loose you know that you stretched the pockets. If they go in same as normal then don't worry about it.

I shoot a hot Varget load in my 6BR in all sorts of weather conditions and have never had heat cause any issues for me.

It may have been because of the resizing making the case smaller inside causing slightly higher than normal pressures.

 

[NormB]

I'm going to post this here because it was done in the course of "precision shooting";

Today I shot at a "Tactical / Pecision" match and it was HOT, around 30-35'C hot.

My usual load of preference in my .223 Rem T3 action is 24.4gr of Varget, CCI Br4s, Winchester brass and Berger 80gr VLDs. I've fired probably 300-400 rounds of this load all with the same brass. I have been running the brass through a Lee Collet neck sizing die. During my last outing I notice that the bolt was stiff after firing a few rounds but there was no flat primer problem. I went home and ran the brass though a Redding full length sizing die and reloaded the ammo with the same load.

Today, after shooting (my bad) is when I noticed that the primers on all my fired brass are very flat. During shooting I never notice any sticking bolt problems. So ...

a) did I resize my brass too short and thus greatly increase pressure?
B) did the high tempreature today increase the pressure enough to cause flat primers (I don't think I've been shooting this load in tempreartures over 25'C?

And most importantly, IS THIS DANGEROUS??? If its not the end of the world I will fire off the remaing 14 rounds on a cooler day.

Or, can I load up what's left of these full length sized cases and keep shooting the same load to fireform them again? Other wise, I may buy a new batch of brass.

Thoughts???

Resizing too short will cause head space problems. This will allow primers to back out against the breech. When the case slams back against the breech it flattens the primers. Looks like high pressure, but isn't. Like mentioned above. If primers seat OK, not loose, no worries. Adjust your sizing die to not push the shoulder back so far.

NormB

 

[Tikka223]

Perfect, thanks for the input gents!

 

[Conte]

Oh, oh, I got this. I have a lot to say about this so bare with me.

I shoot a Tikka 223 myself. And jsut happen to have quickload running in front of me with my gun specs dialed in.

What's you're OAL and barrel length ? And what's your twist at that ?
Mine is 22"

According to my Data here, that load @2.55" OAL would generate 57487psi.
SAAMI max is 5500psi.

In big red lettering it says "DO NOT USE THIS LOAD". Hah.

Yeah, you may have dodged a grenade this time. I don't suppose you were going by the Hodgon Website ? Their listing is for a diff bullet.

According to my data, you absolute max is 24g of that powder @ 102.7% case fill and a 97.22% burn in a 22" barrel. If your barrel is longer, it would get worse.
If you have a 1/8 twist like mine, you don't have to push them that hot, in fact you shouldn't, the fast twist is to accommodate the slower speed of the heavier bullets
You should be able to find a sweet spot in about the 2500 range.
If you have a 1/12 twist, then consider a lighter bullet like 69g.
I've gotten sick groups with as little as a 55g bullet with an under min charge of 18g of IMR4198.
Man, that load shoots amazing but I don't like to use it, cause the lack of pressure doesn't seal the brass case in the throat properly.


Some people might call BS on my for quoting Quickload, but this program has nailed loads for me before, and I've even used it to predict max loads, and when attempted, sure enough I saw mild over pressure signs.

I would check the brass for signs of head separation. If the brass does not appear fatigued, I'd use it again, or save it for a reduced load.

I've been working up loads for my T3 223 for about 2 years now. The most accurate powder I've shot from it to date is IMR3031.

I was having similar problems with 80g bullets. They shot great but I maxed out my pressure before I got them to the Velocity I wanted. I'm now working on loads using 75g BTHP's. Last time out I shot 4 bullets @ 100y @ 0.383 @ 2451fps using 21g of 3031 @ 2.275"

I got a bit more pressure headroom so I'm going to try and bump it up about 50fps.

Try 23g of your Varget.

Oh and one more important thing, if this load worked great for you before, but all of a sudden is maxing out now, it might be the Copper Factor.

If you aren't diligently cleaning that barrel you could have a build up of copper fouling that is causing the pressure increase.

Furthermore, even if you have been cleaning properly, If your T3 is anything like mine, the barrel overheats a bit too fast causing the copper to build up 3 fold on a hot day.
In other words, as you shoot, your barrel got smaller, and the pressure would build up more with each round.

I have the T3 Lite, so the barrel isn't really designed to shoot the way I shoot it.
I have to make sure to let it cool down a bit between groups, and even at that, I still am going to need about 4x Two day soaks of Hoppes Benchrest to get it all out.

I much prefer shooting that machine in the winter. Ah, does it ever shoot nice and clean in 20 below.

 

[Conte]

Resizing too short will cause head space problems. This will allow primers to back out against the breech. When the case slams back against the breech it flattens the primers. Looks like high pressure, but isn't. Like mentioned above. If primers seat OK, not loose, no worries. Adjust your sizing die to not push the shoulder back so far.

NormB

PS: He is using a Lee Collet die, it doesn't work that way. You fire the case, if forms to the chamber, thereby matching the headspace, and every Neck Slizing load after that, the headspace never changes. The Collet die simply squeezes the neck back to spec diameter to load a new bullet and cannot be adjusted to augment the shoulder. It pretty much only has one setting, the right one, and if he backs it out it would not size the neck properly anymore and cause a loose bullet fit.

I use the exact same die to load for my Tikka.

 

[tiriaq]

PS: He is using a Lee Collet die, it doesn't work that way. You fire the case, if forms to the chamber, thereby matching the headspace, and every Neck Slizing load after that, the headspace never changes. The Collet die simply squeezes the neck back to spec diameter to load a new bullet and cannot be adjusted to augment the shoulder. It pretty much only has one setting, the right one, and if he backs it out it would not size the neck properly anymore and cause a loose bullet fit.

I use the exact same die to load for my Tikka.

He was using a Lee Collet die until stiff uplift started, then switched to a FL die.
I would suspect that the stiff uplift developed because of the shoulders not being set back when neck sizing.
The flattened primers after FL sizing could have resulted as NormB suggested.

 

[Conte]

Ohhhh ok, yeah I missed that.

There is usually enough headspace movement from a properly sized case to flatten a primer if the load is too hot. Just because his headspace was so tight before using neck sizing, he never noticed it until he FL sized.

I'm really not worried about his headspace.
If he indeed has put 400 rounds of this load thru his gun without any problems, then all of a sudden gets stiff uplift, unless he botched loading that batch, there is something else going wrong that needs to be addressed. Brass is the least of his problem, he should be worried if his gun is ok, and it's future compatibility with that load.

My vote is copper, until he chimes in otherwise.

I've had that same problem with my Tikka. Shot a little to rapidly on a hot day at the range, got home and the barrels was so coated in copper and fouling I could not even get my spear jag thru it.

 

[Tikka223]

The more I think about it, the more I think it's my FL die that is setting the shoulders much too far back. I have an MR1 and I posted a thread a while ago because I kept getting really dirty cases and I was worried that i was getting a really poor seal in the chamber. For the MR1 I use the FL die each and every time. This could all be my newbie inexpience but it doesn't help that Redding didn't include instructions with the die.

I just looked over my brass and the flat primers are consistent from shot 1 to 36, they are all flat and it doesn't seem to gradually get worse. The recoil also didn't feel any harsher than usual.

I just used an RCBS micrometer to measure so of the fired cases vs unfired cases;

The fired cases all measure around 0.25-.0.35
The unfired cases all measure around -0.43 (as in right before it hits the "zero" line.

I'm not to sure what these numbers mean and because of that I seldomly use the mircrometer, I just use it to check consistency.

As for specs on the rifle, it's a T3 action with a 1" contour Shillen barrel that is 26" long with a 1/8" twist that I use to shoot 80gr VLDs. I worked up to the 24.4gr load of Varget and found it to be one of the accurate loads. The next more accurate node would be 23.8 ish but I often shoot out to 800m so it's nice to have the higher velocity to stay supersonic.

 

[Conte]

It is possible that your FL die is set wrong. It would not be with the Lee dies that I use, but I'm not sure how your die works.

Just bare in mind. YOU ARE running an over max pressure load,
according to SAAMI specs.

Even when a 223 brass is correctly sized to spec headspace, there will be enough play to flatten your primer with a load that hot.

Your gun that likely handle over 60000 before it turns into a grenade.
62000 roughly according to my research and you're at 57500. |
Something to think about.

The fired cases all measure around 0.25-.0.35
The unfired cases all measure around -0.43 (as in right before it hits the "zero" line.

What is the a measurement of ?

As for your MR-1, you're "not supposed" to neck size for an auto loader, but I believe that to be a myth. DO NOT neck size for your M305 unless you have a lyman headspace gauge to screen your loads before firing them.

The reason your brass is coming out dirty is likely due to the auto function.
The brass is being pulled loose of it's seal before the powder is finished burning and you're getting excessive blow back.
It's that or the load you're using is too light.

Let me know what load you're using in your MR-1 and I can crunch some numbers for you.

IF you're using Varget, that explains part of the problem. It's slower burning for longer barrels, and the powder is still burning long after the bullet has left the barrel and the action has started to cycle.

If the problem persists, I would recommend trying a faster burning powder.
Again, I recommend 3031, it's in a burn rate sweet spot for the 223 with most loads achieving 98% efficiency or better.

I would also try 4198, it can burn to 100%, and it sure as #### can group if you rub it the right way.

 

[manitou210]

Group of shooters in Ottawa shooting F class semi benchrest competions, all have used Berger 80gr VLDs 80.5 Bergers and 80gr Sierras over the last 3 or 4 years we have fired over 6000 + rounds with Varget and more grains of powder than you are using but under Hogdons Posted Max of 25gr.
Barrels are all Custom 28 to 30" 1/7 twist or 1/8Twist.
Never have had problems like you are having, brass is Lapua and some have been fired over 25x times using Redding bushing neck sizer and bumping shoulders back as needed.
Many powders we have tested will spike in heat expecially if loaded ammo in sunlight even in plastic ammo box. Powders that are bad in heat VT500 series, RL 15,2520 very bad powder in heat. Any of hogdons Extreem powders a okay in heat Varget H 4895 etc
I would pull bullets and check weight of Varget,Also measure lenght of your brass if your above 1.757 or 1.758 you must trim your brass.
Measure the size of your fired brass necks if the measure .252" or smaller your chamber could be to small using thick brass like Lapua, may have to neckturn
Maybe Norm has something check it out

 

[Tikka223]

So here are some pictures of the fired FL sized brass and primers;

The primer on the left is a "normal" primer from a fire case.

I reloaded the brass and only Lee Collet neck sized them this time, assuming the cases are fireformed to the chamber again. Fired a batch off and everything looks normal again;

So the verdict: I'm pretty sure I pushed the shoulders back on the cases too far causing the primers to get flattened on the bolt face. I don't think this was due to overpressure.

Thanks for all the input!

 

[thecollector]

If your T3 is anything like mine, the barrel overheats a bit too fast causing the copper to build up 3 fold on a hot day.
In other words, as you shoot, your barrel got smaller, and the pressure would build up more with each round.

As a barrel heats up and thermal expansion has its way, the ID increases, not decreases.