@ 10:28 am (GMT)
Luke LahdenrantaI have a standard Remington M700 SPS in 7mm Remington mag. I have been making up dummy cartridges to establish some cartridge overall length to begin hand loading for it. So far what I have got for max COAL are for example with a 162 gr SST is 3.373 inches and with the 160 gr Woodleigh PP 3.365 inches and 3.395 for the 150 gr Swift Sirocco II
Also got 3.33 inches with the 160 gr nosler partition and 3.31 inches 175 gr Swift A frame max COAL to round out my measurements so far.
What I am wondering is how these measurement might compare with other 7mm Rem Mag COAL, does my rifle have a pretty standard throat length? Or is it fairly short for overall length of throat? I have read something of people successfully lengthening the throat on their M700 7mm mags to be able to use more of the M700 box magazine and gain a little more velocity potential? I'm not sure if I would go to that trouble, I think I would probably just go 7mm Practical but I am still curious how my rifles throat compares to other 7mm rem mags.
@ 07:07 am (GMT)
Re: 7mm Rem Mag Throat and Cartridge Overall LengthHi Luke, that sounds like it is either max SAAMI or possibly about .010 longer than max SAAMI specs. You would not want to go any longer than this (throat wear will cause this anyway).
In its current state, other projectiles which you have not tested will produce longer OAL's but with the bottom of the bullet set well in the case neck.
As you say, if more power is needed, ream it to 7mm Practical.
Hope that helps.
@ 08:01 am (GMT)
Re: 7mm Rem Mag Throat and Cartridge Overall LengthThank you Nathan that does help to give me a point of reference for working with this rifle, my first 7mm mag.
Interesting that it is actually on the long side for throat length. That may help to explain the slow velocities I have been chronograph for factory ammo. I am getting only about 2900 and change with Remington 150 gr CL and about 2760 fps with the 175 gr CL. The Federal load with 165 gr GK bullet is getting about 2820 fps. So about 150 fps less and with the 26" barrel length. On the positive side accuracy so far has been pretty decent for a stock unbedded SPS.