Blown primers on New Hornady 6.5 Creedmoor brass HELP

[Ggmac]

What size is the flash hole in the new brass ?

 

[spooksar]

Could be bad brass I had some Hornady factory 460 S&W ammo, it blew out the primers. Contacted Hornady and they said they had a run of bad brass. Give them a call

 

[Grimstod]

Like Swd said. Shoot the 6.5x47 and never look back.
Its more accurate and cheaper to reload for anyway.

 

[XTR]

The ejector marks indicate to me it is a pressure problem not that the pockets were loose to start with.
You state that the only thing you have changed from your old load is new brass.
Things that could cause it.

• Thick necks causing tight fit and not letting bullets release? Check loaded rounds compared to old brass, and measure the neck on the fired brass compared to the neck on the loads you made. BR shooters sometimes shoot pretty tight specs, my F-TR rifles shoot with nearly .010 clearance. If your clearance is just a couple of thou then this has the potential to be a problem.
  
• Brass over length? Mouth of the brass pinching the bullet and not allowing release. Check length compared to old brass
  
• Brass not the same capacity as your old brass. You can expect that your old brass will have a slightly greater capacity, that's normal. I kind of doubt this one but it's worth a check.
• Measure the shoulder on the new brass vs the fired brass. I think "go/no-go" gauges in a 308 have about .010 difference. You should definitely see less stretch than that in your brass.

 

[HardrockZ28]

Update, still have more measuring to do.

I have been measuring every step of the way taking the brass apart that I have not shot yet.
So far the only thing that is different from some of my other once fired Hornady brass that was loaded with the same powder charge and primers.
The once fired brass weighs in at 145.00 average in grains and this new brass that is giving me hell weighs in at 150.00 average.

So this new brass is 5 grains heavier than any other brass I have on hand.

New brass OAL was a little short on all the cases so no trim was needed..

I will measure the flash holes and let you know what I find.

Will measure the head space and let you know what I find.

Will measure the Neck diameter and let you know as I have not completed taking all the loads down

On the question on weighing or dropping - I weigh each load one at a time, and the loads that I have taken down I am reweighting the powder and each one so far is right at 41.15

Will work on these again tonight and let you know what else I find.

Thanks everyone for your help and ideas, I just want to know what went wrong and why.

 

[jlow]

Update, still have more measuring to do.


The once fired brass weighs in at 145.00 average in grains and this new brass that is giving me hell weighs in at 150.00 average.

So this new brass is 5 grains heavier than any other brass I have on hand..

There you go. Heavier brass means less volume, means greater pressure. It is not exactly earth shaking news to people shooting .308 that LC brass is heavier, less volume, and require a reduction in load. This is no different.

 

[JLT]

FWIW, RL17 is one of my go-to powders in my .260 AI. I'm running 43.7 gr. in fireformed IMI and WCC brass behind a 140 in a case with roughly 10% more capacity than the CM. That's a warm but safe load in my rifle, producing an average velocity right at 2,950. It seems to me that you're above your rifle's maximum for that collection of components. I'd drop back and work back up. RL17 tends to be peaky, just like an old God-fearing quarter liter two stroke - you have to pay attention when it 'comes on the pipe'.

 

[AckleymanII]

I would also check the headspace of the new cases.

+1

Loose headspace can leade to similar issues. Smoke the shoulder on a new case and see if you have firm contact in your chamber.

Your load is on the hot side, fire formed cases vs new cases issue?

 

[basshusker]

Hornady brass is not that strong. 6.5 creedmoor is only really good for 3 to 4 firings with the box load. Those are overpressure in any case it looks like.
This why I suggest to people 6.5x47L or .260 if you plan reloading. You could switch to .308 palma brass that somebody forms for you. Problem with Lapua brass is that it is strong and hide overpressure situations.
I would encourage you to ditch that batch. Kind of funny when you see all of this "once fire 6.5 Creed" brass on the hide. There is a reason besides people just shooting factory ammo IMHO.
J

 

[basshusker]

This is one of the biggest problems I have with the design of the Creedmoor. Hornady way over rated the PSI. The cup design of the Creedmoor is the same as the 260 or 308 which are rated for 60,000psi while Harnady gave the Creedmoor a rating of 62,000. Way to hot. It is why Creedmoor brass does not last very long. Lapua did their 6.5x47 right though by making the cup thicker and using small primer.

+100

 

[fguffey]

I have been measuring every step of the way taking the brass apart that I have not shot yet.

Every step? I suggest you start by measuring before and again after. I would suggest you measure the diameter of the case head. Case head expansion is normal and to be expected and then there is what is considered normal. For ever normal has been .00025". When the case head expands .00025" the primer pocket does not expand nor does the diameter of the flash hold. There is one thing a reloader can count on, if he is hammering his case heads with heavy loads the diameter of the case head is going to expand and the case head is going to get thinner from the cup above the web to the case head. I know, that means nothing to most but for those that can keep up with all the other stuff when the case head shortens the case head moves away from the case body. So hammering your case heads could be considered a bad habit.

F. Guffey

 

[CaptainMal]

Hopefully his measurements will be done and reported back. With those ejector marks my guess is headspace with the possibility of recent carbon fouling building a ring that has also increased pressure.

 

[fguffey]

+1

Loose headspace can leade to similar issues. Smoke the shoulder on a new case and see if you have firm contact in your chamber.

Your load is on the hot side, fire formed cases vs new cases issue?

Reducing head space is rather involved. it is made easier for those with a savage type jam nuts adjusters. To me it seems easier to reduce clearance because the case does not have head space. Then it gets complicated, I believe pressure is reduce when there is clearance as in the case is shorter from the shoulder to the case head than the chamber from the shoulder of the chamber to the bolt face.

F. Guffey

 

[HardrockZ28]

Ok have now finished all the measurements, took a little longer as live got in the way again.
Here is what I have found, thinking that this batch of brass do to the weight 5 grain over my other Hornady brass has caused the pressure problems.

Once fired cases same powder load and lot as well as the primers. Neck sized only Brass
Case weight was from 144.60 grain to 145.70 in batch of 50
Water measurements
Case weight with primer 150.90 grain
Case weigh with water 203.80
Shoulder measurements 1.5340
Note it takes 2 firings to make the brass grow to the point that I have to then full size the brass
When I full size the brass to bump the should back .002 full size cases are then 1.533
After 2nd firing they measure 1.535, no problem with bolt lift but when neck size only they are starting making the bolt a little tight on bolt close.

Now the problem new brass
Case weight was from 147.75 grain to 150.60 in batch of 50 - Most of this brass is from 149.90 to the 150.60 range
Water measurements
Case weight with primer 155.20 grain
Case weigh with water 207.35
Shoulder measurements on fired brass 1.5340
Shoulder measurements on un fired brass 1.5315
Neck size
Shot brass 2.996
Loaded brass 2.993
Flash hole is .080
All powder fill was right on to my 41.15. Checked every one of the tear down loads just to make sure I did not mess up.

So I’m thinking and I might be wrong – The new bras is heaver then the brass and less case volume then on the brass I have been using, causing the case fill to be at max or a little over max do to the internal size of the brass (thicker wall)

 

[CTK]

This is educational for those of us on the sidelines. Lesson in diagnosing weird over pressure. Thanks to all commenting!

 

[jlow]

Ok have now finished all the measurements, took a little longer as live got in the way again.
Here is what I have found, thinking that this batch of brass do to the weight 5 grain over my other Hornady brass has caused the pressure problems.

Once fired cases same powder load and lot as well as the primers. Neck sized only Brass
Case weight was from 144.60 grain to 145.70 in batch of 50
Water measurements
Case weight with primer 150.90 grain
Case weigh with water 203.80
Shoulder measurements 1.5340
Note it takes 2 firings to make the brass grow to the point that I have to then full size the brass
When I full size the brass to bump the should back .002 full size cases are then 1.533
After 2nd firing they measure 1.535, no problem with bolt lift but when neck size only they are starting making the bolt a little tight on bolt close.

Now the problem new brass
Case weight was from 147.75 grain to 150.60 in batch of 50 - Most of this brass is from 149.90 to the 150.60 range
Water measurements
Case weight with primer 155.20 grain
Case weigh with water 207.35
Shoulder measurements on fired brass 1.5340
Shoulder measurements on un fired brass 1.5315
Neck size
Shot brass 2.996
Loaded brass 2.993
Flash hole is .080
All powder fill was right on to my 41.15. Checked every one of the tear down loads just to make sure I did not mess up.

So I’m thinking and I might be wrong – The new bras is heaver then the brass and less case volume then on the brass I have been using, causing the case fill to be at max or a little over max do to the internal size of the brass (thicker wall)

You got it... This is why it's worth weight sorting brass and if you see something extreme like this, take proper action. Also think if this is enough to cause a problem, the lesser difference may not blow your primers but it will affect the location of your accuracy node - again why we weight sort.

Those who says weight is not related to volume is a bit delusional. If I tell you it is 10 grains heavier do you believe there is a volume problem? If it is 5 grain, what do you think? So 1-2 grain difference magically has not effect. This is a total failure in logic.