Ammo Test - 270 & 300 WSM

In 2004 I acquired one of the new Winchester Silent Shadow Model 70 rifles in the then new 270 WSM (Winchester Short Magnum). Based on a the 404 Jeffry case this short-action magnum was at the time breaking new ground and competing head to head with numbers like Weatherby’s 270 Mag and similar. A year later when I went to Africa for the first time I wanted something powerful and the 270 WSM fitted the bill.

Years on I now own three WSM-chambered rifles – the original Winchester 70 has been re-barrelled in 300 WSM, a Browning BLR Lite also in 300 has been added and I now have a Browning X-Bolt in 270. I have here two factory offerings from Winchester to look at.

270

The 270 WSM is from Winchester’s newer Power Max Bonded line. This is less exotic than a lot of their earlier ammo and offers a bonded cored, protected hollow point bullet in a plain brass case. The ogive (nose) is pre-notched to ensure rapid expansion, but the strong design means more weight/mass retention. The bullet weighs 130-grains, which over the chronograph was clocking an average of 3215 fps/2998 ft/lbs through the X-Bolt. This is 60 fps lower than the factory figure, so not bad. As you can imagine it shoots flat and fast and could be a bit destructive on smaller deer. Accuracy-wise it comes in under the inch, with an average of .75” @ 100-yards.

The 270 WSM is a sort of Super 270 Win, where you might need that extra power and range. A ball park figure for the Power Max Bonded 270 Win shows 3069 fps/2718 ft/lbs at the muzzle. Healthy figures and well up to any deer species we might encounter. But if required the extra speed/energy offered by the WSM might well be attractive.

300

Identical in principle and case size the 300 WSM obviously offers the option of a bigger calibre and heavier bullet choice. In this it’s treading on the coat tails of that all time great the 300 Winchester Magnum, though offering the advantage of a short action receiver. Tests I have run in the past show that it’s only about 100 fps slower than the Win Mag.

I still use the long discontinued 180-grain Fail Safe load, as I bought 200-rounds and horded them. Generally this is a good weight for the 300 WSM giving energy figures well in excess of 3000 ft/lbs and a good speed and therefore trajectory. On test is the 180-grain Super-X Power Point, which is a reasonably standard jacketed soft tip. Over the chrono it was making 2900 fps/3378 ft/lbs, through my Model 70, again under the factory-quoted 2970 fps, which was expected. A comparable Win Mag is giving 2960 fps/3519 ft/lbs. Accuracy with the Super-X was 1 – 1.5” @ 100-yards, not as good as my Fail Safe load but still well within limits. Overall a great heavy hitter for just about any animal!Identical in principle and case size the 300 WSM obviously offers the option of a bigger calibre and heavier bullet choice. In this it’s treading on the coat tails of that all time great the 300 Winchester Magnum, though offering the advantage of a short action receiver. Tests I have run in the past show that it’s only about 100 fps slower than the Win Mag.