The 7mm Shooting Times Easterner (7mm STE)
By Chuck Hawks
The 7mm STE was designed by Layne Simpson, a gun writer, in 1987 and introduced to the shooting world at large in the May, 1989 issue of Shooting Times magazine. It is the running mate of the successful 7mm STW, which was adopted by Remington and now is a SAAMI standardized cartridge. Of the two, the 7mm STE is probably the more useful cartridge for most North American hunting, although it remains a wildcat.
The rationale for the 7mm STE is similar to that for the 7-30 Waters, a rimmed 7mm cartridge for use in Marlin and Winchester lever action rifles. It is based on a .307 Winchester case (itself a rimmed version of the .308 Winchester case) necked down to accept .284" (7mm) diameter bullets and fire-formed for greater powder capacity. The STE case has a 40 degree shoulder and minimal body taper.
Because the parent .307 Win. case is bigger than the .30-30 parent case of the 7-30 Waters, the 7mm STE significantly outperforms the 7-30 Waters with maximum loads. On the other hand, .30-30 brass is far more available to the reloader than .307 Winchester brass.
The rim diameter is .506" and the base diameter of the 7mm STE is .470". The neck is .270" long and the COL is 2.015". Except for the neck length, these dimensions are identical to the .307 Win. case. Chamber pressure should not exceed 52,000 cup, the same as for the .307 Winchester.
Recent manufacture Marlin and Winchester lever action rifles in .30-30, .307 Winchester, .356 Winchester and .444 Marlin can be converted to 7mm STE merely by rebarreling with no other modifications necessary. RCBS supplies 7mm STE reloading dies and Clymer Manufacturing can supply a chamber reamer.
The most common bullets for the 7mm STE are the 120 grain Nosler and 139 grain Hornady. These are flat point bullets designed primarily for the 7-30 Waters. Pointed bullets may not be used in the tubular magazines of Marlin and Winchester rifles.
H414, W760 and Reloader 19 are regarded as top powders for the 7mm STE. According to the 26th edition of the Hodgdon Data Manual, 42.0 grains of H414 powder behind the 120 grain Nosler bullet is good for a MV of 2581 fps. A maximum load of 47.0 grains of H414 can drive the same bullet at a MV of 2916 fps.
The Nosler bullet has proven excellent for North American deer and antelope. Zero that bullet (at a MV of 2900 fps) 3" high at 100 yards and, as reported in the Hodgdon Data Manual, the bullet should hit 2" high at 200 yards and 6" low at 300 yards. That is a very useful trajectory for Eastern or Western deer hunting!
With the 139 grain Hornady bullet, 40.0 grains of H414 yields a MV of 2346 fps and a maximum load of 45.0 grains of H414 delivers a MV of 2706 fps. These Hodgdon loads used WLR primers, reformed Winchester brass, and were tested in a 22" barrel with a 1-10" twist.
As with the 7-30 Waters, bullet supply is the main limiting factor for the 7mm STE. The 139 grain Hornady bullet, for instance, is regarded as the best choice for use on game larger than deer. Unfortunately, Hornady has recently discontinued that bullet.
Speer offers a Special Purpose 130 grain flat point bullet for the 7-30 Waters that should be useful. Unfortunately, Speer has not published reloading data for that bullet in the 7mm STE. I would suggest starting with minimum load data for the 139 grain Hornady bullet and working up from there, chronographing and watching carefully for signs of excess pressure. I would ultimately expect muzzle velocities in the vicinity of 2800 fps or less at maximum acceptable pressure, and I certainly would not try to push MV beyond 2800 fps with the 130 grain Speer bullet.
Copyright 2005, 2012 by Chuck Hawks. All rights reserved.