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Old 06-30-2019, 06:58 PM
Tony F Tony F is offline
Join Date: Nov 2009
Posts: 137
Default Small Rifle 7 1/2 Primers

Are 7 1/2 primers for max loads / Benchrest? From what I've read difference between 6 1/2 and 7 1/2 is a pressure issue. Can anyone shed some light on this? Thanks in advance.
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Old 06-30-2019, 07:21 PM
X Hunter X Hunter is offline
Join Date: Oct 2009
Posts: 1,370

Do not to use the 6 1/2 primers for AR rifles.
The 7 1/2 primers are good to go in the AR rifle.

Primer Cup Thickness
Rem 6 .020”
Rem 7 .025”

The 6 primer is for cartridges like the 218 Bee and 22 Hornet. If you use them for 223/5.56 they will be pierced by the firing pin. The jet of hot gas will flame cut the tip of your firing pin and the subsequent cartridges will pierce more frequently due to the, now sharp, firing pin tip. Ignore the issue and the flame will open the firing pin hole in the bolt face and possibly etch the bolt face.

There is verbiage on the box that says Rem 6 primers are not for use in the AR15 or 223 cartridge, or something to that effect.

Last edited by X Hunter; 06-30-2019 at 07:49 PM.
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Old 06-30-2019, 08:22 PM
DougS DougS is offline
Join Date: Oct 2009
Posts: 331

The 6 1/2 is good for .30 Carbine, and the 7 1/2 as noted is good for the 5.56/.223. You could use the 7 1/2 for the .30 Carbine, but why?
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