A couple of years back, I was fortunate enough to be on a hunting trip where I got to see the brand-new Sierra GameChanger (SGC) projectiles in action – what I saw was impressive. Also on the trip was NZRod&Rifle’s John Herbert, who was reviewing the new ammunition, and I watched him pull off an awesome shot – knocking over a sika hind at just under 500 yards and absolutely flattening it. Watching that happen was enough for me – I had to know more about these new projectiles from Sierra.

If you’ve read other articles I’ve written, you’ll already know I’m a big Sierra bullets fan and have been for many years. I started using them about 20 or so years ago in my first long-range rifle, which was a Remington model 700 chambered in 7mm STW (Shooting Times Westerner) – I used the 150-grain Sierra MatchKing (SMK); they’re superb bullets, and I’ve secured many awesome trophy and meat animals with them. Unfortunately, in more recent years, Sierra have made changes to their MatchKing bullet line-up, and my favourite ones were included in the changes. Watching the GameChanger (GC) projectiles in action on that hunting trip made me interested to see how they’d perform in my own rifles – so the timing of these new SGCs is ideal – my stash of SMKs is starting to get low!

New to the GameChanger Range

The 7mm 150-grain projectile is new to the range and will complement the 165-grain option currently available; in the .30 cal, there’s a new 125gr and a 180gr – both of which are great additions to the extensive range of .30 calibre chamberings. For me personally, the new 7mm 150gr will be a great bullet to run in one of my 7mm Rem Mags, and in the .30 cal, the 180gr is a projectile weight I’d like to run in my .300 Win Mag.

Unfortunately, I’d only just recently sold my .308, which is the exact calibre I wanted to test the new 125-grain GC projectile. The .308 is still one of the most popular calibres used today – many hunters own short-barrelled rifles chambered in this calibre, which could possibly benefit from a lighter weight projectile option. I didn’t have to look too far for a .308 to borrow; Jake Bindon, one of my Rivers to Ranges staff, owns a standard Remington Model 7 in .308 – a superb rifle fitted with a Hardy suppressor and Leupold scope … and very accurate.

At the Reloading Bench

The first thing I do when starting a new load development is to measure the chosen projectile’s rifling touch overall length, which is done using my Hornady overall length gauge and bullet comparator. This is so I can see exactly how much I’ll be jumping the projectile before it makes contact. For me, one of the most important things is having the reloads fit the magazine and have them feeding properly out of the magazine. I’m not a fan of seating a projectile out to try and achieve slightly better accuracy or velocity which, in turn, makes the rifle a single shot because they can’t fit in the magazine.

Generally, the most popular powder used for the .308 cartridge is ADI 2208 or Hodgdon Varget, so I decided to start with this powder for the 125grn GC load development – Jake had some good quality, once-fired cases that he’d given me to use.

I use Federal primers as my go-to primer as they’re readily available.

After reading my Sierra Bullets manual, I started with 46 grains and continued up to 49 grains for my powder charges – I prefer to do a group test each powder charge and see how each group performs while recording velocity and being ever watchful of pressure signs; I also learned that this powder would need to be compressed with the bigger powder charges, so care is needed with a powder funnel with this combination.

At the Range

After shooting the prelim loads, Jake’s rifle really liked this lighter new bullet and it performed reasonably well overall with all the powder charges resulting in velocities from 2700-2900 FPS. However, wanting to get the best I could with accuracy for this new projectile, I started to play with the seating depth – pushing the projectile deeper into the case and also adding half a grain of powder to one of the best groups I shot, which was 48 grains and .9″ accuracy. I then loaded and shot the 48.5-grain powder weight with the deeper seating depths and nailed the accuracy with this powder and primer combination – and, of course, it fits the magazine.

Settling with this load, the velocity was 2840 FPS, and the accuracy was under half MOA at 100 yards. I then shot the rifle at 400 yards to test the longer-range accuracy and verify the bullet drop; with that done, it was time to go hunting and see how these bullets performed on a deer.

Out Hunting

My youngest daughter (8 years old) definitely has my hunting genes – she’s super keen to go for another hunt with Dad, so she was excited to come along on this trip.

We arrived a bit later than normal, but that’s to be expected when you have a child with you. We made our way out to the main gully on the block where I do some of my local guided hunts, and it wasn’t long before we spied a few red deer feeding on the bush edge. Cutting this distance down a little, I found a good spot to set up the rifle – the range was just over 260 yards to the deer, and there was a slight crosswind.

After getting comfortable, I waited for the hind to turn completely broadside so I could get a good solid shoulder shot on her. I squeezed the trigger … she reared up in the scope closely followed by the good sound of a solid hit as she disappeared from my view – a few more deer appeared and quickly departed.

We decided to take the long way down to where the deer was just to give her a little more time to expire; on our way we came across a yearling that was left behind from the swiftly departing deer. Malia was desperately trying to convince me that we needed another deer for the freezer; so, with a now front-on shot available on the yearling, I squeezed the shot off – she ran fewer than 20 yards before collapsing. I gutted the yearling and took particular note of the extensive damage this bullet had done to the animal’s vital organs.

Arriving at the second deer, which had gone about the same distance as the yearling – under 20 yards and the shot was bang on – I saw the bullet hadn’t exited, but the damage on this animal was also pretty extensive.

My Thoughts on the 125gr GameChanger

I skinned and boned the two deer out after they’d spent a week in my chiller, and I’d have to say these lighter projectiles simply did the business; they do seem to be very explosive, as I never found a solid projectile, but I did find fragments.

Although I was hunting red hinds on this occasion, I’d recommend the heavier GC option if you’re hunting for bigger-bodied animals like a red or sambar stag. I was impressed with the projectile’s accuracy. Another important factor was the lack of recoil while using this lighter bullet, which would be a good option for junior hunters or if recoil is causing you a bit of grief.

GameChanger 7mm 150 and 30 Cal 180 Projectiles

I’m just starting the load development for the other two new Sierra GCs – I’m going to try out the new .30 cal 180 grain for my Remington .300 Win Mag guide rifle; and for one of my 7mm Rem Mags, I’ll try out the new 7mm 150 GC – so make sure you keep an eye out for the results in an upcoming issue.

Note: Load developments for this review were all done to manufacturer guidelines, which worked for the test rifle. Always follow safe reloading practices, manufacturer guidelines and prescribed load data when developing loads for any rifle.