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haze10
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Posted: 6/26/2009 9:03:14 AM
.025"
Measured one yesterday. This is the same as the Rem 7-1/2. While I know there are other variables in addition to cup thickness, at least for me, .025" means I am going to try them at normal pressure loads, maybe even a few at max load to see what they do.
brickeyee
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Posted: 6/26/2009 1:19:39 PM
Originally Posted By haze10:
.025"
Measured one yesterday. This is the same as the Rem 7-1/2. While I know there are other variables in addition to cup thickness, at least for me, .025" means I am going to try them at normal pressure loads, maybe even a few at max load to see what they do.


Thickness is a small part of the strength.
Brass hardness (work hardening from manufacture) is very significant.

When drawing cartridges the head is work hardened and left that way for strength, while the brass often must be annealed (softened) to allow forming the neck.
ma96782
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Posted: 6/26/2009 1:26:05 PM
Not to mention that the alloy used could be different and the priming compound formula and amount used could be different from one mfn to the next.

But........by all means..........do your experiments and report back.

Aloha, Mark

haze10
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Posted: 6/26/2009 2:07:03 PM
Guys, a dial caliper is about as far as my metullogical skills can take me in my garage. I wish I could do a full spectrum analysis. I would not discount thickness as easily. If the alloys are even close in composition they are going to have reasonably similar tensile strenghts.

There has been no technical info available at all on these primers so at least I have answered one variable.
ma96782
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Posted: 6/26/2009 5:37:12 PM
[Last Edit: 6/26/2009 5:45:09 PM by ma96782]
haze10,

Don't get me wrong.

It's just that some people reading here..........may just assume things, based solely on the thickness issue.

Note: Federal's Standard Sm Rifle primers measure .019" in thickness and they work with .223 Rem. pressures. YMMV, due to other issues.

Remington 6 1/2 primers measure .020" in thickness and they do not recommended it with .223 Rem. re-loads.

But, Good or Bad......it's the ARFCOM way.

Aloha, Mark

PS............I suspect that you'll be fine with Magtech SR primers..........but, that is solely based on the lack of "very vocal" complaints.

Then, you may get the people that say to use ONLY Magnum SR primers with ammo meant for use in a rifle with a floating firing pin (such as the AR15).

That's also the ARFCOM way.





coochie32
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Posted: 6/26/2009 6:44:33 PM
haze10, I actually worked up a load today using Magtech SR primers for my AR. I only put 50 rounds down range but I had no issues with the primers. I worked up to the max published load for my powder and bullet combination and didn't see anything out of the ordinary.
gs1150
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Posted: 6/26/2009 11:25:43 PM
Originally Posted By coochie32:
haze10, I actually worked up a load today using Magtech SR primers for my AR. I only put 50 rounds down range but I had no issues with the primers. I worked up to the max published load for my powder and bullet combination and didn't see anything out of the ordinary.


Not meaning to pry, but what was the load?
Just got some of the Magtech's myself.
Were your results comparable to what you were using before?
When in doubt, shoot it.If your not sure,shoot it AGAIN !!

FUCK OBAMA
ziebart
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Posted: 6/26/2009 11:46:11 PM
I just fired 15 in my ar15 today. They all went boom and made a little group compared to 50 grain federal bulk pack. I was trying to do a ladder test but apparently 186 yards is too close. I was loading 24 to 26.7 tac in .2 grain increments with a 52 grain HPBT Sierra and lake city brass. I will post up the ladder test later to see if anyone has an idea how to read it.

I also tried them in my 9mm CZ-75B, as I read that SP can be substituted with SR. It worked ok but I did have some that keyhold in the target and some that required a second strike. I have never had any problems with this pistol using factory ammo. I think I need to tweak my process to load lead as this is my first attempt at that which may explain the keyholes.
AeroE
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Posted: 6/27/2009 12:10:16 AM
[Last Edit: 6/27/2009 12:16:14 AM by AeroE]
Originally Posted By haze10:
Guys, a dial caliper is about as far as my metullogical skills can take me in my garage. I wish I could do a full spectrum analysis. I would not discount thickness as easily. If the alloys are even close in composition they are going to have reasonably similar tensile strenghts.

There has been no technical info available at all on these primers so at least I have answered one variable.


The thickness and alloy are important, but the degree of work hardening of the primer cup is exceedingly important. Brass has an enormous range of strength and ductility between its annealed condition and full hard condition, and this detail simply cannot be neglected. All the alloy really tells us is how the material will behave mechanically. Strength varies with the square of the cup thickness, so this has a strong influence; a very small increase in thickness adds lots of strength (and stiffness, too).

A Google search on Olin Brass or Olin Alloy 260 will turn up lots of good info from Olin's brass mill.

It's true, Obama is the Leader of Fools deluded to believe, "Everything is going to change now".
As for me, I will embrace what is Right more tightly than ever.


1 lbf = 32.174 lbm-ft/sec^2
coochie32
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Posted: 6/27/2009 11:07:44 AM
Originally Posted By gs1150:
Originally Posted By coochie32:
haze10, I actually worked up a load today using Magtech SR primers for my AR. I only put 50 rounds down range but I had no issues with the primers. I worked up to the max published load for my powder and bullet combination and didn't see anything out of the ordinary.


Not meaning to pry, but what was the load?
Just got some of the Magtech's myself.
Were your results comparable to what you were using before?


LC 05 once fired brass
55 gr Nosler Ballistic Tip
Ramshot TAC - Started at 23.5 gr ended at 26 gr (Nolser and Ramshot suggested max load at 26, Sierra 26.3)
Magtech SR primer

I settled on 25.5 gr of TAC which is the same charge I use when using the exact same components with CCI 400 primers




haze10
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Posted: 6/27/2009 11:56:19 AM
Keyholing wouldn't have anything to do with the primer. Hard strikes to me is a good sign. These are rifle primers so you'd want the cup to be hard.