Low pressure reloads in the .222 Rem. and the .257 Roberts??

[zeke mccune]

Hello All:

Can somebody tell me why the pressures in these two cartridges are so low when compared to other modern cartridges? There is about 10,000 psi difference between these two cartridges and other modern cartridges.

Tia,

Zeke

 

[glp]

With the 257 Roberts

Hello All:

Can somebody tell me why the pressures in these two cartridges are so low when compared to other modern cartridges? There is about 10,000 psi difference between these two cartridges and other modern cartridges.

Tia,
And 100 gr bullets you are operating in the 51-55,000 psi range
Why do you call that low pressure

 

[zeke mccune]

Hi glp:

The books that I was looking at were giving pressures in c.u.p which is meaningless to me. I thought that I was reading in p.s.i. I will go to some on line powder reloading information which may list pressures in p.s.i.

Here is some information that made me question the low pressure idea:

All in thousands

222 Remington 41-49 cpu

257 Roberts 33-47 cpu

7mm Rem Mag 51-55 cpu

220 Swift 46-52 cpu

The 22-250 had pressures that nearly equaled the Swift. Strong case?

In any case, hanks for taking the time to reply.

Be well,

Zeke

Perhaps the cases are constructed heavier with the Swift and the 7mm Rem mag.