Peterson Virgin Brass Pressure Signs

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FNG1001

Sergeant of the Hide
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Sep 5, 2022
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#1
New to Peterson 6.5 Creedmoor SRP brass. Picked up a couple boxes and thought i'd fireform it first with some Hornady 140 gr i have available.

I shot 10 and started seeing what looked like pressure signs, though I could be wrong (first time trying Peterson brass). I stopped after these initial firings just to be sure, and inspect.

Shoulders grew 0.004
Gordon Reloading Tool warns of pressure >40 grains.

My question is: has anyone experienced similar results using Peterson brass, or with virgin brass? I plan on dropping the charge on the remaining cases and seeing how they do.

Details:
Brass: (0x fired - Virgin) Peterson 6.5 CM SRP
Powder: 38 gr H4350
Bullet: 140 ELD-M Hornady
Primer: Federal 205
COAL: 2.838
CBTO: 2.203
Case length average: 1.912
Peterson reported average case volume (H2O): 50.6 grains

Brass Prep:
Tumbled
FL resized to fix necks (no change to shoulder)
Chamfered & deburred
 

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#2
Any sticky bolt lifts? What’s the diameter of the case web now vs before firing? More than .001 expansion is a sign of overpressure but I don’t see anything alarming on your case heads….how did those rounds print? shoulders growing .004 is no big deal. Just set your fl sizing die so it bumps them back .002
 
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#4
FNG1001 said:
New to Peterson 6.5 Creedmoor SRP brass. Picked up a couple boxes and thought i'd fireform it first with some Hornady 140 gr i have available.

I shot 10 and started seeing what looked like pressure signs, though I could be wrong (first time trying Peterson brass). I stopped after these initial firings just to be sure, and inspect.

Shoulders grew 0.004
Gordon Reloading Tool warns of pressure >40 grains.

My question is: has anyone experienced similar results using Peterson brass, or with virgin brass? I plan on dropping the charge on the remaining cases and seeing how they do.

Details:
Brass: (0x fired - Virgin) Peterson 6.5 CM SRP
Powder: 38 gr H4350
Bullet: 140 ELD-M Hornady
Primer: Federal 205
COAL: 2.838
CBTO: 2.203
Case length average: 1.912
Peterson reported average case volume (H2O): 50.6 grains

Brass Prep:
Tumbled
Chamfered & deburred
Click to expand...
That's good data to help diagnose what might be going one, except velocity with barrel length would be really helpful too.

That 38 grs of H4350 shouldn't be giving you anywhere near any pressure signs, though the pictures of the head suggest your close. But that might be because you need a little more powder since you're loading a bit long???
 
#5
I have loaded Peterson 6.5CM for several years now. After adjusting the charge for the slightly less case capacity I landed on a charge of 41.6 gns of H4350 with a 140 eldm on top and have never seen pressure from that load. That said had a friend go through the same process and have similar reaults as you, but it was not pressure. He shoots an RPR and ended up that his presumed cratering was from a sloppy bolt face and firing pin fitment. He had it busched and all of the supposed cratering went away. YMMV
 
#7
Get some CCI 450’s SRMagnum primers. The cups are thicker. Or. Go back to LRP brass or get the bolt bushed. Had one doing the same thing. Swapped back to LRP brass and primers and good to go.
 
#11
.004 from the cases being that much short on the first firing is what is causing the ejector marks. When the case head accelerates backwards after being driven forward by the firing pin. Make the cases a crush fit on the first firing will stop the ejector marks and possibly the primer cratering. Expand the necks to 7mm then run them in your sizing die and create a false shoulder for the first firing.
 
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#14
Screw your sizing die out so it doesn’t push the shoulder back and try to chamber it. When it sizes the body it will push the shoulder forward. Then screw the die down until it chambers with a little resistance. That will be your cartridge base to shoulder datum length. Check that against your virgin brass and that’s the difference in length. Your virgin brass will not be completely fire formed on the first firing. Especially not at 38 grns unless you are jamming your bullets.
 
#15
Thanks for everyone's thoughts and experiences on this! I'll be shooting the rest today (slowly). Will update once i have more data. Also cleaned the bore and bolt to start from a clean slate. To include taking the ejector out and giving everything a cleaning.

nn8734 said:
Any sticky bolt lifts? What’s the diameter of the case web now vs before firing? More than .001 expansion is a sign of overpressure but I don’t see anything alarming on your case heads….how did those rounds print? shoulders growing .004 is no big deal. Just set your fl sizing die so it bumps them back .002
Click to expand...

I cant recall any sticky bolt. Biggest concern I had was when looking at the case heads and seeing the ejector marks, but also from these old eyes, the primers looked slightly cratered+flattened.
Forgot to mention in the brass prep that after tumbling, and before chamfer/deburr, I ran all the brass through a FL resizer just to get the necks concentric (edited now). No change in shoulder in doing this.

Thank you for suggesting to measure the case web. Unfortunately, I already ran them through a FL sizing die. For what it's worth, even through already FL resized, looks like the case web grew by 0.002 consistently across those fired (new out of box = 0.4675)



Cascade Hemi said:
Bushing the bolt and switching to 450's won't fix the ejector swipes.

@FNG1001 bump 2.00 grains up and reshoot.
Click to expand...

Will be working up to it slowly today. Will update once i have more data.

spife7980 said:
Seems about right for peterson being the junk it is.
Should be harder on the second firing and I doubt you see the issue then.
Click to expand...

I was thinking it might be due to it being it's first firing, but i have never had these marks show up with similar loads on Hornady or Norma brass.

JOE62 said:
.004 from the cases being that much short on the first firing is what is causing the ejector marks. When the case head accelerates backwards after being driven forward by the firing pin. Make the cases a crush fit on the first firing will stop the ejector marks and possibly the primer cratering. Expand the necks to 7mm then run them in your sizing die and create a false shoulder for the first firing.
Click to expand...
This was my thought too, that the 0.004 might be a bit much of a gap in the chamber. I'll be shooting the rest today (slowly). Will update once i have more data.
 
#18
The.004 was after firing if I read it right. The cases grew .004 in length to the shoulder on the first firing shooting 38 grns of H4350. The cases did not fully fire form to chamber dimensions on the first firing with that load. Cases are likely.006-.008. shorter than the chamber when unfired. The OP could try neck sizing only the once fired brass and then he would have a closer representation of his actual chamber length. Also a good call on the neck clearance.
 
Last edited:
#19
spife7980 said:
I think it’s definitely not in the top
Click to expand...

Glad I'm not the only one who feels this way. When 6CM was a new thing, and all you could get was Hornady, I was happy when Peterson came out with their SRP 6CM Brass. The first time I shot it, I got the same sport of pressure signs the OP is showing (at similarly low loads) and had issues getting the primers out. Not too long after, Lapua came out with their 6 and 6.5 CM brass and all things were right with the world.

The only good thing about my 6CM Peterson experience was that I broke so many primer pins on the brass that it turned me toward getting a Harvey Deprimer.

That said, Peterson is my only choice for my 37XC, and it's holding up pretty well.
 
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#21
Shot the remaining 50 rds. I got the same plunger marks on all case heads, however, no other signs of pressure and the bolt throw/lift was normal.

I went ahead and reloaded another set of 50: 10 strings of 5 rounds from 39.0 - 40.8 grains of H4350.
My brass prep was the normal:
  • tumble
  • anneal (2 sacrificial Peterson brass gave me 146 and 147 AZTEC code on the AMP),
  • FL resize (0.002),
  • trim to size (1.910),
  • powder+seat bullet (COAL = 2.8380, CBTO = 2.2170).
Looking at the heads, same marks, but operating the bolt felt smooth. A close up of the case heads' (max charge 40.8 grains) primers doesn't show any flattening. I'm starting to think the ejector marks aren't a concern (please correct if you think otherwise), and could just be a combination of my bolt with this brass.

Average speed of x1 fired: 2608 - 2739 fps (39.0 - 40.8 grains H4350)

I still have a couple of unfired boxes of this brass that i can compare measurements to with x1 and x2 fired.
 

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#22
JOE62 said:
The.004 was after firing if I read it right. The cases grew .004 in length to the shoulder on the first firing shooting 38 grns of H4350. The cases did not fully fire form to chamber dimensions on the first firing with that load. Cases are likely.006-.008. shorter than the chamber when unfired. The OP could try neck sizing only the once fired brass and then he would have a closer representation of his actual chamber length. Also a good call on the neck clearance.
Click to expand...
Where did you read that? .006-.008 seems like pure speculation, also .006-.008 proabay isn't going to produce ejectors marks either. The cases I have seen it on have been belted mags growing in the .015+ area anyway.
 
#23
Cascade Hemi said:
I think I have at least 2k pieces of Peterson 6CM and 6.5CM brass. I have had less defective Peterson cases in all 2k pieces than the last single 100pc box of Lapua brass.
Click to expand...
This is why I quit using lapua brass when I reloaded which has been over 2yrs ago...1 box of Lapua had 20 pieces that the necks looked like someone stepped on them.
 
#25
FNG1001 said:
Shot the remaining 50 rds. I got the same plunger marks on all case heads, however, no other signs of pressure and the bolt throw/lift was normal.

I went ahead and reloaded another set of 50: 10 strings of 5 rounds from 39.0 - 40.8 grains of H4350.
My brass prep was the normal:
  • tumble
  • anneal (2 sacrificial Peterson brass gave me 146 and 147 AZTEC code on the AMP),
  • FL resize (0.002),
  • trim to size (1.910),
  • powder+seat bullet (COAL = 2.8380, CBTO = 2.2170).
Looking at the heads, same marks, but operating the bolt felt smooth. A close up of the case heads' (max charge 40.8 grains) primers doesn't show any flattening. I'm starting to think the ejector marks aren't a concern (please correct if you think otherwise), and could just be a combination of my bolt with this brass.

Average speed of x1 fired: 2608 - 2739 fps (39.0 - 40.8 grains H4350)

I still have a couple of unfired boxes of this brass that i can compare measurements to with x1 and x2 fired.
Click to expand...

What is your neck clearance?
 
#35
supercorndogs said:
Please qualify, "back in the day." And how it has changed since "back in the day." Better yet, maybe you should start your own thread and do so.
Click to expand...
Butt hurt because someone said lapua brass is not the gold standard anymore...funny!!

15 years ago when I bought a box lapua brass I did not get crushed necks or folds in the shoulders so you tell me how it has changed.
 
#38
Some people are awful charitable regarding defects with one company while holding other companies to a zero tolerance standard.

OP may have gotten soft brass, switch to something else and see what happens. I doubt .004" is enough bolt thrust to cause the issue but you can check it by jamming the lands.
 
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#39
DellaDog said:
I dunno about Peterson = junk.

I have 20 firings on the same Peterson 6.5 brass loaded at 41.5 gr 4350 through 3 barrels.

I have not lost a single piece to pressure or loose pockets.
Click to expand...
Don't believe a word he writes .He loves to talk bullshit , probably never touched a piece of Peterson brass in his life . As you will notice he backed down from "Junk" to this when called out . Like most people here in the reloading department , just screaming for attention .
1677681680477.png
 
#40
Haney said:
Don't believe a word he writes .He loves to talk bullshit , probably never touched a piece of Peterson brass in his life . As you will notice he backed down from "Junk" to this when called out . Like most people here in the reloading department , just screaming for attention . View attachment 8086447
Click to expand...
Rich coming from the guy who asked why gun ranges dont also grow weed.
And I backed down because its obviously not s&b bad. But I sure wouldnt call it good.

Its junk because they cant hold primer pocket depths to within a thousandth and they also cant control neck thickness to less than a thousandth.
Nevermind the fact that under 40 gr in a creed leaves my pockets loose at only five firings.

At least they have learned to center up the flash holes now.
 
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#41
Cascade Hemi said:
I don't generally make claims I can't support, see above. I've posted the picture here before and got more than a few me too's.
Click to expand...
That is one folded neck. your statement made it sound like its a matter of business practice. What you could have said to avoid confusion would have been, "I got a piece with a folded neck once."

Granted, how i am supposed to know that is a piece of Lapau brass?
LR1845 said:
Butt hurt because someone said lapua brass is not the gold standard anymore...funny!!

15 years ago when I bought a box lapua brass I did not get crushed necks or folds in the shoulders so you tell me how it has changed.
Click to expand...
No, I asked for you to qualify your statements, because it lacked any basic information, and you just made a dude-bro statement.

You still have not.

iu


The worst Lapua brass I have had was a couple hundred pieces of Lapua Gold Box 243, and that was also "back in the day."

Of course they are not visually inspecting every peice they make and some bad pieces will get through. No body is, and everybody has some bad ones get through. I can say that is the first fold I have seen in Lapau brass. I have seen them in most other brands.

Most products have taken a hit in quality over the last 3 years. I haven't bought much during these trying times. :ROFLMAO::ROFLMAO::ROFLMAO:
 
#42
Cascade Hemi said:
Some people are awful charitable regarding defects with one company while holding other companies to a zero tolerance standard.

OP may have gotten soft brass, switch to something else and see what happens. I doubt .004" is enough bolt thrust to cause the issue but you can check it by jamming the lands.
Click to expand...
I didn't say anything about any other brand chief...And I didn't see Spife say anything about Lapau.
 
#44
supercorndogs said:
That is one folded neck. your statement made it sound like its a matter of business practice. What you could have said to avoid confusion would have been, "I got a piece with a folded neck once."

Granted, how i am supposed to know that is a piece of Lapau brass?

No, I asked for you to qualify your statements, because it lacked any basic information, and you just made a dude-bro statement.

You still have not.


The worst Lapua brass I have had was a couple hundred pieces of Lapua Gold Box 243, and that was also "back in the day."

Of course they are not visually inspecting every peice they make and some bad pieces will get through. No body is, and everybody has some bad ones get through. I can say that is the first fold I have seen in Lapau brass. I have seen them in most other brands.

Most products have taken a hit in quality over the last 3 years. I haven't bought much during these trying times. :ROFLMAO::ROFLMAO::ROFLMAO:
Click to expand...
So I'm going to say 2005 or 2006 was the last time I bought lapua brass(back in the day)I had 20 pieces out of 1 box that the necks were crushed like they'd stepped on not just minor dings...if i remember correctly(you know the bro-dude thing)had 30 case like that out of 300pcs(3 boxes)and 10 other pieces with that same fold in the shoulder like Cascade Hemi posted.

And I agree just about everything has taken a hit in quality but prices have done nothing but go up...part of the reason I stopped reloading and just buy factory ammo.
 
#49
@918v
0.2910 after FL resize and no bullet.
0.2925 with bullet seated

Bullet is a Hornady 140 ELD-M measuring 0.2635 average.

Measurements taken from a Mitutoyo CD6 ASX.
 
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