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slimjim Super Member


Joined: May 16, 2009 Posts: 8317 Location: Fort Worth TX
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Posted: Sun Nov 06, 2011 2:29 am Post subject: .223 Pressure Indications |
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Dawgdad, shrpshtrjoe, and others could help me out with this one. I was inspecting my cases from Friday's range session for any signs of over-pressure. With the large rifle primers in my .270, the primers begin to flatten noticeable as pressure builds. When there is a ridge around the firing pin crater that I can catch my fingernail on, I know I am too hot for that rifle. I don't think the small rifle primers flatten out as much as the large primers do. The picture below is all the cases from my 70gr GMX load. The top left is 23.6 grains of Varget. The other 3 are 24.1 grains. The primers don't look like they are flattened much at all but all the primers from 24.1 grains have a ridge around the firing pin crater. Can anyone confirm this is too much pressure?
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_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
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Vince Site Admin


Joined: May 25, 2005 Posts: 15929 Location: Brisbane AUSTRALIA
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Ominivision1 Super Member


Joined: Sep 20, 2010 Posts: 2984 Location: Iowa
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Posted: Sun Nov 06, 2011 4:54 am Post subject: Re: .223 Pressure Indications |
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From the photos they look fine, but it's impossible to judge pressure by primer appearance alone. Different makes or even batches can vary in cup hardness which of course makes it impossible. Take two cartridges from the same box and fire them in different rifles and the primers appearance can be very different. There are simply too many variables and if you believe that you can judge pressure from looking at primers alone then you only fooling your self and walking a very thin line.
Other things to look for hard case extraction after firing, appearance of other marks on the case head / base outside the web, carbon traces around primer. If your .223 suddenly recoils and sounds like a .30/06, you may want to investigate your load data no matter what the fired case looks like. 
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Bushmaster Super Member


Joined: Jun 12, 2005 Posts: 11452 Location: Ava, Missouri
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Posted: Sun Nov 06, 2011 7:56 am Post subject: Re: .223 Pressure Indications |
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You might also have a look at the firing pin hole in the bolt face. It might just be a bit over sized allowing the primer to show (indicate) cratering. If so. Not to worry.
Your primers do not indicate over pressure. Also Primers, even the flattened ones, do not indicate over pressure unless they are cratered, show metal flow, smokey (sooty) around the primer or a punctured primer are the indicaters of over pressure, but not flattened primers.
I would have a look at your firing pin and hole in the bolt face.
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TRBLSHTR Super Member


Joined: Mar 23, 2007 Posts: 1071 Location: Lower 48's-left coast(near portlandia)
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HayCreek Member


Joined: Sep 10, 2011 Posts: 36 Location: Central ND
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Posted: Sun Nov 06, 2011 11:39 am Post subject: Re: .223 Pressure Indications |
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+1 to all above.
There are several indicators of overpressure. But, primer condition is not conclusive. What I see, here, is normal. When we speak of flattened primers, we mean the pronounced loss of radius on the primer cup.
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slimjim Super Member


Joined: May 16, 2009 Posts: 8317 Location: Fort Worth TX
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Posted: Sun Nov 06, 2011 1:21 pm Post subject: Re: .223 Pressure Indications |
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Thanks for all the feedback. I haven't loaded the .223 much nor pushed the upper bounds of performance. I'll keep a close eye as I progress.
_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein |
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Dawgdad Super Member


Joined: Feb 08, 2006 Posts: 1065 Location: On the Prairie
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Posted: Sun Nov 06, 2011 3:20 pm Post subject: Re: .223 Pressure Indications |
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I load the 77's hotter than that.. you will likely run out of case capacity with the neck of the longer heavier bullets taking up more inside volume before you max out pressure. I can hear the Varget crunching now...
Keep going unless you have a tack driver load at that velocity.
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shrpshtrjoe Super Red Neck Member


Joined: Jan 26, 2005 Posts: 2965 Location: Maryland
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Posted: Sun Nov 06, 2011 3:49 pm Post subject: Re: .223 Pressure Indications |
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I think they look pretty good . My 70 grain TSX Load is 24.5 grains of Varget
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SyberShooter Member


Joined: Jul 23, 2010 Posts: 93 Location: Arizona
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Posted: Mon Nov 07, 2011 7:43 am Post subject: Re: .223 Pressure Indications |
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In addition to what others have said, also keep an eye out for metal flow marks on the brass rim from the ejector recess. It will show up as a shiny spot. You also didn't mention what primers you use. CCI are harder and the CCI 41 are military grade hard, but yours appear brass colored so I will guess they are Winchester, which are about middle of the pack as far as hardness and thickness of the metal cup IMO.
Another item I did not see is what type of gun are you shooting? Bolt or Semi or?
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HayCreek Member


Joined: Sep 10, 2011 Posts: 36 Location: Central ND
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Posted: Mon Nov 07, 2011 10:17 am Post subject: Re: .223 Pressure Indications |
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Here's a link to data on primers. Should help in choosing the right primer for your loads:
www.jamescalhoon.com/p...essure.php
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PaulS Super Member


Joined: Feb 18, 2006 Posts: 4330 Location: South-Eastern Washington - the State
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Posted: Mon Nov 07, 2011 11:25 am Post subject: Re: .223 Pressure Indications |
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Those primers look very nice. The ring around the pin strike looks to be from an oversize firing pin hole and not from pressure but check to be sure. The primers all have a nice radius around the pocket and don't seem to be showing much in the way of over pressure.
If that is the only indication of pressure you have at this point then I would say that things are fine.
Check case growth, head separation, signs of extractor impressions, loose primers and sticky cases - those are signs of immediate over pressure. Ptimers that are flat to the edges of the primer pocket are also a red flag of too much pressure.
_________________ Paul
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Speer, Lyman, Hodgdon, Sierra, and Hornady = reliable loading data
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Bushmaster Super Member


Joined: Jun 12, 2005 Posts: 11452 Location: Ava, Missouri
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Posted: Mon Nov 07, 2011 1:13 pm Post subject: Re: .223 Pressure Indications |
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I wouldn't say a "red flag". Maybe a "yellow flag"...I have a Colt SAA in .357 magnum that will flatten the primers. and I mean FLATTEN with only 13.5 grains of 2400 under a 140 grain SJHP. I would need at least one more reason to consider over pressure than just a flatten primer.
_________________ I have one nerve left and yer standin' on it...
DEMOCRACY Two wolves and one sheep voting on what to have for lunch...
LIBERTY A well armed sheep contesting the outcome of the vote... |
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slimjim Super Member


Joined: May 16, 2009 Posts: 8317 Location: Fort Worth TX
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Posted: Mon Nov 07, 2011 2:38 pm Post subject: Re: .223 Pressure Indications |
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SyberShooter wrote: |
You also didn't mention what primers you use. ... I did not see is what type of gun are you shooting? Bolt or Semi or? |
Remington primers. AR but with the gas turned off (basically a straight-pull bolt action).
_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein |
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slimjim Super Member


Joined: May 16, 2009 Posts: 8317 Location: Fort Worth TX
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Posted: Mon Nov 07, 2011 2:48 pm Post subject: Re: .223 Pressure Indications |
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Thanks shrpshtrjoe, HayCreek, SyberShooter, PaulS for additional information.
_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein |
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