Yes, I found this on some other forums.
Do not use 6.5 srp in high intensity rifle carts. such as the .12 Rem, .222 Rem and the .223 Rem. Damage to firearm and/or serious injury may result.
They are used in the .22 Hornet.
Do not use with loads exceeding pressures around 38000 psi CUP and load with those. I wouldn't exceed 40000 psi.
In rifle cartridges, the 6-1/2 small rifle primer should not be used in the 17 Remington, 222 Remington or the 223 Remington. The 7-1/2 BR is the proper small rifle primer for these rounds.
Warning: When primers are selected incorrectly, misfires, damage to your firearm, and/or personal injury may occur. Visit the ballistics tables on our website. Recommended primers for each rifle and pistol cartridge are listed in these tables.
The above is straight from Remington. the 6 1/2 SR primer is meant for 30 carbine and other cartridges with lower operating pressures.
The primer cup in the 6 1/2 is softer and if used in max or near max loads in .223 (for example) you WILL have a high percentage of pierced primers.....
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