Discussion Forums

Nathan Foster

Over the last few months I have had four email queries asking about the viability of a .270-.300 Win Mag. I have decided therefore to post my thoughts on this potential wildcat here.

For a start, we need to be aware that we have two .270 magnums, the Weatherby and the WSM. As power levels go, the order is: the .270Win, then the .270WSM and then the big boy, the .270 Weatherby. This excludes such wildcats as the .270-08.

The .270 Weatherby is similar in case dimensions to the 7mm Rem Mag, .338 Win Mag and .264 Win Mag which we call the 2.5" magnums. Besides the radius shoulder, the Weatherby differs in two primary areas- 1. the case neck is very long to aid 2. the long freebore which is used as a gas expansion chamber to enable ultra high velocities. Bullet jump is around 1/4" depending on loads etc.

Some shooters have an interest in creating a short freebore .270 Magnum. Such a wildcat would allow room for seating depth experimentation. The one weakness of a long freebore cartridge, is that barrel harmonics cannot be manipulated via seating depth if the barrel is temperamental.

In short magazine long actions such as the Ruger M77 long action, the mag box is ideally suited to a 2.5" magnum, therefore a wildcat based on either the 7mm Rem Mag or a short throat Weatherby is ideal. A short throat Weatherby will produce velocities identical to the 7mm rem Mag with the potential to drive 150gr bullets at up to 3200fps.

In longer actions (long mag boxes), there is potential for a .270-.300 Win Mag. Velocities would be the same as the Practical, up around the 3300fps mark with a 150gr bullet.

So now we have addressed the 'can it be done', we should really look at why and whether a .270 wildcat is worth it?

The .277 caliber is literally a cats whisker thinner than the .284 (7mm) caliber. A sliver of sellotape is 5 thou in diameter, the difference between the .277 and .284 calibers is 7 thou. Some folk can't even see through a 7 thou gap in a set of verniers- the gap is so fine.

It certainly seems like an awful lot of trouble to go through, creating a wildcat that is so close to 7mm. Furthermore, the 7mm magnums offer the hunter a wider range of projectiles, particularly the heavy weights such as the 175gr Partition as well as heavier frangible bullets. The .270 wildcat on the other hand, has a limited range, though this is changing to some extent now.

One hunter asked this: "I have been using the 140 grain Accubond in my .270Win, it performs so well, I was wondering how it would perform in a magnum wildcat, if it would help extend its usable range". What this hunter needs to be careful of is creating a situation where the AB is pushed too fast, losing the good performance that was witnessed in the .270Win, towards a situation where the AB now performs well- but only between the ranges of 200 and 450 yards, meeting too much resistance at close ranges (good wounding but no shock and very slow killing) and on the flip side, narrow wounding at long ranges where core bonded bullets are unable to deliver fragmentary wounding in the absence of high velocity.

Trying to extend the long range performance of a core bonded bullet is a trap for both intermediate and experienced players. In the example of an intermediate experienced shooter, he may find himself at a point where his skills are such that he is shooting further than his optics are designed for and is able to connect at ranges of lets say 500 yards, but finding that the core bonded bullet is not performing well. For many, it is natural to think, if I could just up my MV by 150-200fps, buy new optics and get set up for long range- all will be well again. But what tends to happen, is that the shooter buys his optics, gets set up, then within a couple of months, his goal of fast killing at 500 yards is long conquered and he is now trying to shoot at 700-900 yards and now finds once again, that his bullet is not up to the task.

The above example sounds naive doesn't it. But it is a perfectly normal chain of events that I see and other long range shooters will be nodding their heads now in agreement, having seen the same. What really irks me, is when experienced ballisticians use the same mode of thinking. I think it abysmal that men hold such esteemed positions in the world of ballistics, yet lack a basic fundamental understanding of ballistics. The two prime examples are the Barnes Long Range bullets and the new Nosler Long Range Accubond. Both have two goal design parameters, a very high BC and reliable expansion at low velocities. I don't give a flying faq if a small bore bullet can expand at 1200fps because at 1200fps, in the absence of disproportionate to caliber wounding (high velocity wounding), rather than a 2.5 to 3" internal wound, the expanded bullets in question will create wounds of around .5" in diameter. The same could be done with a .45-70 over a century ago- big bloody deal. The .45-70 also had 400 grains or so bullet weight in its favor, packing its own style of punch. Death as a result of solids used in the .45/70 is often delayed but clean, thats at woods ranges with fairly good shot placement. Have a look at the meplat article for more on this digression.

Many hunters have no idea just how cruel and slow killing a small wound like this can be, especially if we put wind drift into the mix. But then who can blame them, if we are to believe the latest sales pitches, all we need is an expanding bullet and presto, venison for dinner. Have a look at my 7mm practical Matrix tests on the blog, you won't see perfect shot placement there- you'll see the reality of long range hunting and wind drift. If those Matrix bullets produced a .5" wound due to low velocity, how do you think things would have turned out. Look at the video, trace the path of the bullets and really think about it- look at the size of the internal wounds created by a fully frangible bullet.

Always, if we want to get into the more advanced aspects of game killing, we have to have an understanding of the tools we use- that includes the bullets. If you were a red man on the great plains 400 years ago, it would make no difference. You would know that some arrows in your quiver were OK, some shafts were horrible and would soon yaw. You would have your favorite sharp arrow head, honed as best you could, a few others to back it up and some that weren't so sharp or shapely. Preparation would consume hours and days, living and breathing hunting, a fundamental understanding of game killing.

Getting back to the .270 wildcat magnum...

I have a couple of suggestions that may be used as a basic rule of thumb. If you are a die hard fan of the .270Win and want to explore a magnum option excluding the WSM and WBY designs, then yes, go for it and enjoy it.

If however you are looking simply for magnum power and medium bullet weights for long range hunting, a 7mm Magnum offers a wider range of options in the bullet department.

All of the above being said, there is now a .277" bullet that gives the .270 an edge, the 165gr Matrix VLD with a BC of .738. This can be used in 1:10 twist barrels. There is also a very new bullet from Matrix, a 175gr VLD with a BC of .7828. The .270 cal test bullets I have here are very soft, ideal for long range work on medium game. The 175gr bullet has potential for large heavy bodied deer. Outside of the Matrix brand, there are only a couple of projectiles that I am truly fond of in the magnum .270's, these being the 150gr SST and 150gr Partition, each has various strengths and weaknesses as described in the KB.

Building a .270 wildcat magnum with the single goal of employing the 165gr bullet, 1:10 twist, with the option of utilizing standard .277" bullets is something I would again only recommend to those who are great fans of the .270 caliber. We all have fond memories of a particular caliber or cartridge. The original .270Win is without a doubt the kind of cartridge that brings success after success, great memories, good times. I can see why hunters would want to explore the .270 further. For those able to utilize Matrix bullets, I think the experience will be immensely rewarding.

As for me, I am still a fan of the parent .270Win. A fascinating aspect of the .270Win is that it can produce very spectacular results with relatively low recoil. A .270Win is a boon to shoot after a week at the range shooting magnums. I like the fact that the 150gr SST can be driven fast (2900-2950), producing ideal performance out to a range of around 650 yards. Yet velocity is not so fast as to cause limited penetration on tougher animals- including a memorable Texas heart shot on a boar that spun on the spot as a client took up his trigger at a range of 20 yards (annealed SST). I enjoy the ongoing spectacular kills with the 150gr Partition. Ofcourse these are two bullets that I also enjoy at magnum velocities although the SST behaves differently at close ranges. Yet another incredible load is the 130gr GameKing, used on light game. But if this bullet is pushed too fast, it can meet too much resistance and performance wanes. Now I can enjoy the long range prowess of the Matrix. There is a wide range of .277" bullets that show a balance that I do not like to disturb. The WSM pushes velocities up a tad, performance being similar to the .270Win, but extending its usable range. At Weatherby velocities, rules change and we have to be a bit more careful about bullet selection versus game species versus range. This in no way means that .270 Weatherby performance is poor because it is a great cartridge, a spectacular cartridge when employed in an optimal manner. Also, I have no doubt that the Matrix bullets will perform well at magnum velocities, used at long ranges.

What is required, is an understanding of how major changes in muzzle velocity effect bullet performance.