Why I Made the Switch to Copper:

Developing a .375 Ruger Load for Admiralty Island

by Rueben Glaves

 

I started developing a copper load for my .375 Ruger in the summer of 2025, with fall and winter hunting on Admiralty Island in mind. Hunting there means I always have brown bears in the back of my mind, particularly later in the season when bears can still be out and moving around. I wanted a load that would give me confidence if I needed it for a bear, but would also perform well on Sitka blacktail.

I ordered 250-grain T-Rex bullets from Maker Bullets and H4350 powder and began working up a load. Once I had a load I was happy with, I verified the velocity and spent some time at the range practicing with the rifle. The load was shooting groups of about an inch, which gave me plenty of confidence heading into the field.

I eventually hunted with the rifle for two or three days on Admiralty Island and was able to connect with a nice buck. It was a great opportunity to put the load to work in an actual hunting situation, rather than just seeing what it could do on paper.

 

 

What Got Me Interested in Copper

My interest in copper bullets actually started well before I developed the .375 Ruger load. In February 2024, I had the opportunity to test shoot some ballistic gels with copper bullets. I was impressed with how much weight the bullets retained and, honestly, I hadn’t realized just how much my Nosler AccuBond bullets were fragmenting.

That experience got me curious.

I started researching copper bullets more seriously and began testing and developing some of my own loads. So far, I’ve been really impressed with the results. The penetration, weight retention and performance on game have given me a lot of confidence in making the transition.

The .270 was one of the first rifles where I really started working through that process. I’ve used 130-grain Barnes TTSX bullets with 58.3 grains of H4831SC to take caribou on Adak and several Sitka blacktail bucks.

 

Continuing to Experiment

The .375 Ruger and .270 Savage aren't the only copper loads I’ve been working on. I also developed a load for my .284 using 140-grain T-Rex bullets. That load is shooting groups under an inch, and I’m looking forward to getting it into the field and seeing how it performs on game.

One of the things I’ve enjoyed most about this process is seeing the performance of copper bullets across multiple rifles and different hunting situations. Developing a load isn’t just about finding something that shoots a good group at the range. It’s about finding a combination that I trust when I’m actually hunting—something that performs consistently and gives me confidence when the opportunity comes.

For the .375 Ruger, getting a load dialed in for fall hunting on Admiralty Island wasn’t particularly difficult. I wanted something with enough penetration and bullet integrity to give me confidence around brown bears, while still providing reliable expansion on a Sitka blacktail. The T-Rex has given me that combination.

At this point, I’m convinced enough by what I’ve seen that I’ll continue shooting copper and transitioning more of my ammunition selection in that direction.

For me, it’s about more than just bullet performance. I like knowing that I’m putting less lead into the environment where I hunt and reducing the potential exposure for scavengers. And when I can get that benefit while also using a bullet that gives me excellent penetration, weight retention and terminal performance, it’s an easy decision.

I’ll keep developing, testing and hunting with copper—and I’m looking forward to seeing what the next load can do.