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bigcountry

rem. 6 1/2-vs- 7 1/2

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my question is..... whats the difference between the rem 6 1/2 and 7 1/2 primers???????:unsure:

im loading for a .223 r-15 with varget powder and rem brass. using 60gr sierra varminter and 53 gr barnes tsx. all the load data i see is for 7 1/2 primers. i bought both, just in case. any info is greatly appreciated.

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big country,

 

As with so many subjects, there are varying opinions out there, but in my opinion, the 7 1/2 is the better choice for your .223.

 

The Remington 6 1/2 is designed for cartridges like 22 Hornet. 223 Remington is about as high as chamber pressures get with small primer cartridges. The CCI seems to be a special case only in that it's a bit "tougher" but I wouldn't use a standard small rifle primer with max loads. Winchester claims their SR primer is magnum rated. The cup is thicker than any other standard force small rifle primer but is still thinner than any other magnum small rifle primer. The Remington 7 1/2 is the hottest small rifle primer but that's not the reason to use it in 223. It's because of the thicker cup and the chamber pressure of max loads. CCI claims their BR4 is NOT a magnum but it is hotter than their CCI 400 primer and the magnum CCI 450 is not as hot as the Remington 7 1/2 so that puts the BR4 and the 450 very close.

 

Here are some primer cup thicknesses.

 

Rem 6 1/2 - .020"

 

Rem 7 1/2 - .025"

 

CCI 400 - .020"

 

CCI 450 - .025"

 

CCI BR4 - .025"

 

Fed 200 - .019"

 

Fed 205M -.0225"

 

Win SR - .021"

 

CCI says the CCI #41 uses the same .025" cup as the CCI 450 but the anvil angle is different.

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Good info Mikel.......I always thought that the CCI #41 had a thicker cup than standard.....learned something today......I know the large rifle milspec version (#34?) cured a slam fire problem in one of my old milsurp rifles.

 

Do you have a comparative list of primer "hotness" too?? That, along with the cup thickness chart would make a good "sticky".

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GH, I think I may still have that "relative hotness" info kicking around in some archived files; I'll see if I can unearth it and put it up for everyone.

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The Age Of Miracles may not have passed, after all! First search of the candidate files:

 

Hottest at top.

 

Large Rifle:

 

F215

WLRM

CCI250

R 9 1/2 M

WLR

F210

CCIBR2

CCI200

R 9 1/2

 

Small Rifle

 

Fed 205

R 7 1/2

WSRM

Fed 200

WSR

CCI BR 4

CCI 400

Rem 6 1/2

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I use te wolf 223 and Cci 400/#4 for the small rifle primers in my ARs. My understanding of the CCI primers (4/400) is the angle for #4 is best suited for auto and semi auto. 400 are more for single shot. They work with the floating firing pin of the AR but fast cycling is for the #4.

 

 

Thanks for the info mike. Good studf

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