.300 Winchester Short Magnum

History

 
The .300 WSM was the first of Winchesters short magnum family, released in 2001. Remington released their 7mm and .300 short action ultra magnums in the same year and a year later, Winchester released the 7mm and .270 WSM cartridges. Inspired by wildcat experiments, the Dakota cartridges and especially the John Lazzeroni cartridges of the late 1990’s, the WSM family of cartridges are loosely based on the .404 Jeffery case.
 
Brass for the .300 WSM was designed to withstand much higher pressures than traditional belted magnums, enabling the small case to either duplicate or surpass .300 Winchester Magnum factory loads. The ability to utilize these high velocity factory loads without having to hand load was one aspect of appeal to hunters who adopted the .300 WSM. One of the most appealing factors of the .300WSM included the short, portable light weight rifles. Yet for many hunters, it was simply the appeal of a new cartridge design to enjoy and experiment with.
 
Initial loads from Winchester featured 150 grain bullets driven at 3270 to 3300fps and 180 grain bullets driven at 2970 to 3010fps, all running true to advertised specifications from the 24” barreled factory rifles. Olin (Winchester brand ammunition) furnished both highly frangible and extremely stout loads, offering a wide range of performance. The .300 WSM was introduced just as the overly stout Failsafe projectile design was being phased out. For a short time the .300 WSM was loaded with the 165 grain FS at 3125fps and the 180 grain FS at 2970fps before being discontinued in favor of the Elite projectile for use on tough game.
 
The .300 WSM has grown in popularity since its introduction and of the many recent creations, this cartridge has most definitely proven to be a success. Shooters have enjoyed using the .300 WSM in a variety of configurations from ultra-light rifles through to heavy weight 30” barreled long range rigs.
 

Performance

The .300 WSM achieves what its designers intended, duplicating the velocities of the .300 Win Mag from a short, lightweight rifle platform. Generally, the savings in length are approximately 2.5” when using a 24” barrel as opposed to the optimal 26” barrel length for the .300 Win Mag. Nevertheless, there is no free lunch. 
 
While several authorities have stated that the .300 WSM produces more moderate recoil than the larger .300 Win Mag due to the smaller powder charges, in practical terms the recoil level of the .300 WSM in a light weight platform is hefty enough to require highly disciplined technique in order to maintain accuracy at the long ranges where magnums excel. Still, where there is a need for intense weight savings when back pack hunting or alpine hunting, the .300 WSM offers optimum performance. The .300 WSM is capable of driving all bullet weights at suitably high velocities to deliver fast killing on medium game at close through to truly long ranges - providing the shooter has no illusions as to the need for adequate personal shooting discipline and technique.
 
The small weight and length savings of the .300 WSM can be exploited further through the fitting of recoil reducing muzzle brakes or suppressors which ordinarily, on a long magnum, can make the rifle overly bulky. These rifle configurations can be immensely effective, being easier to shoot, allowing for minor changes of technique in the field, without drastic changes in point of impact. 
 
Readers are however advised against adopting suppressors and brakes in the lax fashion that is very common at the time of this writing. Without close attention, both brakes and suppressors can be highly detrimental to accuracy and barrel life. Both suppressors and brakes can cause heavy carbon fouling which can decrease chamber dimensions, increase pressures and lift velocities over the course of a shooting session. Over barrel suppressors trap heat and during rapid fire with light weight barrels, ruin extreme velocity spreads. Winter developed hand loads can produce severe pressures in the summer during rapid/repeat fire. Muzzles can be completely destroyed via moisture condensing onto carbon deposits, causing severe corrosion (including on stainless steel) or in other instances, causing a swaged burr at the muzzle. Both brakes and suppressors are excellent, extremely useful tools but should always be utilized carefully. With either addition, the shooter must be vigilant with both cleaning and shooting methods.
 
The true forte of the .300 magnums is on large bodied medium game at all ranges. Again, the general rule of this author, is that where 90% of the hunters medium game weigh 90kg (200lb) or above, perhaps settling on 320-400kg (700- 880lb) as an upper limit, the .30 caliber magnums show great strengths. The .300’s are ideal for Red deer, Mule Deer, several species of sheep and goat, wild boar and a plethora of other game animals the world over. As a woods hunting cartridge, the .300 Magnum can drive long for caliber yet fast expanding projectiles at velocities suitable for anchoring game with snap shots from all angles and with varying shot placement. As a long range hunting cartridge, the .300 WSM loaded with A-Max projectiles is capable of producing wide wounding out to 1000 yards.
 
In comparison to the .300 Winchester Magnum, velocities are very similar between the two cartridges. In factory ammunition form, the .300 WSM is generally loaded to maximum potential.  
 
With hand loads and using the heaviest of projectiles, the older Winchester Magnum can prove to be more potent, in some instances by as much as 200fps. Rifle to rifle variations do however muddy the waters. The WSM cannot really be accused of being a severely powder cramped design, even though powder capacity is heavily reduced when using long for caliber 208/210 grain projectiles, the WSM is able to achieve velocities of between 2650 and 2730fps, delivering excellent wounding potential out to moderate hunting ranges with controlled expanding projectiles as well as wide wounding out to, at the very minimum, 1000 yards.
 
Chambers of the .300 WSM factory rifles are generally configured with minimal free bore, minimizing bullet jump for optimum accuracy. Although custom rifles built on the M98 action (or custom re-barreling of the Tikka T3) can be utilized to increase COAL’s in order to maximize powder space and velocities, a separate throating reamer must be used to increase the COAL rather than using the standard chamber design measurements.

   

Factory Ammunition

 
Winchester Olin’s light loadings include the 150 grain PowerPoint at 3270fps, the Ballistic Silvertip at 3300fps and the Elite XP-3 at 3300fps.  
 
Both the PowerPoint and BST are good open country performers on lighter game. The 150 grain PowerPoint has a low BC of .294 but thanks to the high muzzle velocity of 3270fps, shoots flat and hits hard out to ordinary hunting ranges. The PowerPoint is fast expanding and very violent, best suited to game weighing less than 70kg (155lb). The 150 grain BST works exceptionally well in the WSM. With a velocity of .424, the BST is a frangible projectile, producing spectacular kills when matched appropriately to game weights. The 150 grain BST makes for a good intermediate long range projectile for use on light framed game weighing less than 80kg (180lb) out to a range of around 700 yards providing the shooter can read the high wind drift associated with low BC bullets.
 
The 150gr Elite is ideally suited to game weighing between 90 and 150kg (200-330lb) but will also tackle larger body weights if need be. Delayed killing is to be expected as velocities fall below 2600fps and especially below 2400fps. Shot placement is the key to success with this type of bullet design, solid shoulder bone shots allowing the XP-3 to work to its strengths. 
 
180 grain loadings from Olin include the PowerPoint at 2970fps, the Ballistic Silvertip at 3010fps, the Accubond at 3010fps, the XP-3 at 3000fps and the Nosler E-Tip at 3010fps.
 
The 180 grain PowerPoint is highly frangible and unique in its performance. This projectile is not well suited to large bodied animals at close ranges but excels on game weighing up to 150kg (330lb) with the ability to produce fast kills on light or lean game where other 180 grain projectiles are often too stout. The 180 grain PowerPoint does its best work inside 300 yards. 
 
The 180gr BST can be a slow killer on light framed game, best suited to game weights of between 90 and 150kg (200-330lb), tackling larger game weighing up to 320kg (700lb) as velocity falls below 2400fps. This bullet design has no means of obtaining controlled expansion and as such, the BST can produce either fragmentary wounding or uniform expansion (and disproportionate to caliber wounding) or a mixture of both. Much depends on what is encountered during penetration. The BST most definitely has its strengths, the key is matching the bullet weight to game weights and suitable ranges.
 
Olin’s 180 grain Nosler Accubond is best suited to game weighing over 90kg (200lb) and up to 320kg (700lb) though its performance on large bodied game is not quite as reliable or emphatic as the likes of the Woodleigh Magnum due to a tendency to shed a large amount of weight during penetration. Nevertheless, the Accubond works very well on large bodied deer at WSM velocities. Fastest killing is achieved at impact velocities above 2600fps (225 yards), clean but slightly delayed killing down to 2400fps (340 yards) with a further delay in killing as velocities fall below 2200fps. The 180 grain Accubond can be used in conjunction with Olin’s BST as a dual load for use on large bodied deer, the Accubond for close range work, the BST for longer range shots. Both projectiles have the same form and BC
 
Olin’s 180 grain XP3 is best suited to game weighing above 90kg, ideal for game weighing between 150 and 320kg (330-700lb). Best performance definitely occurs at close ranges where velocity is high (above 2600fps/230 yards), especially if a level of stopping power is required for safety. The Nosler E-Tip loading to a greater extent, duplicates the performance of the XP-3. Again, the E-Tip does its best work on large bodied game at close to moderate ranges.   
 
Federal produce a single light weight loading for the .300WSM, featuring the 150 grain Nosler Ballistic Tip at 3250fps, roughly duplicating the Olin loading in performance. As has already been stated, this is a very good light game bullet, performing extremely well in the WSM.
 
Federal’s middle weight loads include the 165gr Nosler Partition, the 165 grain Barnes TSX and the 165 grain Tipped Trophy Bonded Bear Claw, all producing 3130fps. As can be expected, of the three, the Nosler Partition is the softest, fastest expanding load, well suited to Mule/Red deer and game of a similar size with the ability to tackle Elk out to a range of around 625 yards. The TTBBC and TSX both do their best work within ordinary hunting ranges on large bodied game, showing fast killing at impact velocities above 2600fps (225 yards), steadily tapering off in performance with more delayed killing at impact velocities of 2400fps (320 yards) and below.
 
Heavy weight loads from Federal include the 180 grain soft point (traditional Hi-Shok, not the Hotcor bullet) at 2970fps, the 180 grain Nosler Accubond at 2960fps, the 180 grain Partition at 2980fps, the 180 grain TTBBC at 2960fps and the 180 grain Barnes TSX at 2980fps.
 
New loads for 2012 will be the 165 and 180 grain Trophy Copper (untested at this time of writing) which will perhaps eventually replace the TSX within the Federal line up.
 
Federals traditional 180 grain soft point is an adequate performer out to moderate ranges. It has a low BC of .385, rapidly shedding velocity, limiting its ability to produce hydrostatic shock past 150 yards (2600fps) however for hunters on a limited budget this is a good bullet for large bodied deer, especially in woods/bush hunting situations.
 
Federals 180 grain Accubond load again duplicates the Olin loading, the same can be found amongst the .300 Winchester Magnum line up. As already suggested, this is a good load for large bodied deer out to normal/traditional hunting ranges. Likewise, the 180 grain Partition, though it has a soft, fast expanding front core, this projectile is best suited to large body weights above 90kg, though with the capacity to produce broader wounding at low velocities (down to 1800fps/660 yards ) where other bullet designs struggle.
 
The 180 grain TTBBC gives hard core penetration but with the ability to produce high trauma on heavy bodied game at impact velocities above 2400fps (310 yards), producing hydrostatic shock at impact at 2600fps and above (200 yards). The 180 grain Barnes TSX does its best work at high impact velocities. Neural trauma (the imputes for coma) tapers off quickly at impact velocities below 2600fps though internal wounding is usually broad and thorough down to 2400fps. The TSX is a fast killer when used on appropriate game body weights at close ranges, producing clean but often delayed killing at ranges past 180 yards.
 

Hand Loading

 
With hand loads it is difficult to exceed .300WSM factory velocities by any great amount. The .300 WSM achieves top velocities with powders in the 4350, ADI 2209 medium/slow burning range while some rifles achieve better results with slower burning powders in the H4831sc, N165, RE22, ADI 2213sc range, requiring experimentation for best results. 
 
From a 24” barrel typical velocities include 3500fps with 130 grain bullets, 3300fps with 150 grain bullets, 3100fps with 165-168 grain bullets, 3000fps with 180 grain bullets, 2800fps with 200 grain bullets, 2700fps with 208-210 grain bullets and 2600fps with 220 grain bullets.
 
This performance is very similar to the .300 Winchester Magnum while using around 12 grains less powder and a 2” shorter barrel. The caveat as suggested earlier, occurs with heavy projectiles. The .300 Winchester Magnum is quite often capable of driving 208-210 grain bullets at 2900fps, some rifles producing 2950-3000fps. Of course, lengthening the barrel of the .300WSM also helps improve velocities at a rate of 20-35fps.
 
It is worth noting that as hand loads for the .300WSM are increased to full potential, in light weight .300WSM rifles, recoil to both the shooter and rifle platform can have a profoundly negative effect on accuracy. In such instances where accuracy cannot be achieved at full pressures, velocities should be lowered accordingly. To this end, it is quite common to find .300 WSM rifles producing best accuracy at velocities of around (for example) 2900fps with 180 grain projectiles, approximately 100fps below maximum potential loads.
 
Due to the fact that the .300WSM achieves similar velocities to the .300 Winchester Magnum, individual projectile performance can be sought within that text as well as being explored throughout the .30-06 text.  

The .300WSM hand loader is somewhat spoiled for choice when it comes to bullet selection, whether bush/woods hunting with the emphatic 180 grain Norma Vulcan, trying core bonded bullet designs, experimenting with the SST bullets or experimenting with the long range projectiles. One projectile that will be explored here before departing ways with the .300WSM is the performance of the 208 grain Hornady A-Max.
 
The Hornady A-Max has a G1 BC of .648, well high enough for long range shooting. For intermediate experienced long range hunters, it is much easier to read wind and connect shots at impact velocities of 1800fps and above while for experienced ‘wind readers’, the A-Max can be expected to produce wide wounding down to 1400fps. At a mild velocity of 2600fps in the .300 WSM, the 208 grain A-Max breaks 1800fps at 650 yards and 1400fps at 1050 yards. From a full potential velocity of 2730fps, the A-Max breaks 1800fps at 730 yards and 1400fps at around 1140 yards. That’s a big punch for a little case.
 

Closing Comments

 
The .300WSM has been without a doubt, a commercial success, boasting great power from a highly portable platform. The modern light weight rifles chambered in .300 WSM are especially ideal for those who climb high to hunt large bodied medium game. The .300WSM is also suited to those who work in low labor intensive industries, who struggle to maintain field fitness between hunts. Yet this portability comes at a price. Light platform .300WSM’s can be difficult to shoot, after all this is a potent magnum regardless of its visually small case size. It seems that with rifles and cartridges, there is never any free lunch. As always, a sound rifle platform, good shooting technique and matching bullet designs and bullet weights to game weights are the keys to success with the .300WSM.
 
 

Suggested loads: .300WSM					Barrel length: 24”
No	ID		Sectional Density	Ballistic Coefficient	Observed  MV Fps	ME Ft-lb’s
1	FL	Win 150gr PP	.226	.294	3270	3561
2	FL	Win 150gr BST	.226	.435	3300	3627
3	FL	Win 180gr AB & BST	.271	.507	3010	3621
4	HL	165gr SST	.248	.447	3100	3520
5	HL	200gr Woodleigh Mag 200gr A-Frame	.301	.450	2800	3481
6	HL	208gr A-Max	.313	.648	2700	3366

 

Suggested sight settings and bullet paths
1	Yards	100	175	286	323	350	375	400	425
	Bt. path	+3	+3.9	0	-3	-5.6	-8.6	-12	-16
2	Yards	100	175	308	349	375	400	425	450
	Bt. path	+3	+4	0	-3	-5.3	-8	-11	-14.3
3	Yards	100	150	278	317	350	375	400	425
	Bt. path	+3	+3.7	0	-3	-6	-8.8	-12	-15.6
4	Yards	100	150	285	325	350	375	400	425
	Bt. path	+3	+3.8	0	-3	5.3	8	11.1	14.6
5	Yards	100	150	249	287	300	325	350	375
	Bt. path	+3	+3.4	0	-3	-4.2	-6.9	10.1	-13.8
6	Yards	100	150	247	288	300	325	350	375
	Bt. path	+3	+3.4	0	-3	-4.3	-6.9	-10	-13.5

 

No	At yards	10mphXwind	Velocity	Ft-lb’s
1	300	9.1	2324	1798
2	300	5.8	2635	2311
3	300	5.5	2468	2434
4	300	6.1	2478	2250
5	300	7.1	2213	2175
6	300	4.9	2298	2439

 
 
 
 

	Imperial	Metric
A	.533	13.53
B	.555	14.09
C	35 deg
D	.538	13.66
E	.344	8.73
F	1.663	42.24
G	.437	11.09
H	2.100	53.34
Max Case	2.100	53.34
Trim length	2.090	53.04

 
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