6.5 PRC Load Development: Bergara Wilderness HMR

If you’re looking for a rifle to hunt big game long-range, there are many factors to consider. Knock-down power, recoil, ammunition and component availability, velocity, ballistics, rifle weight, and many more. At the end of the day, many hunters have settled  on the 6.5 Creedmoor and similar cartridges to hunt big game. And 6.5 PRC literally takes the 6.5 Creedmoor to the “next level” in terms of velocity and performance. In this article, I’ll cover my first load development steps for 6.5 PRC- it’s been fun!

Bergara Wilderness HMR, Athlon Ares 4.5-27x50mm

What prompted this load development? I recently tested the Bergara Wilderness HMR chambered in 6.5 PRC, and while I got great results with the factory ammunition I tested, I had to see what I could do with my own handloads in this rifle. Here’s the full story covering the rifle:

TESTED: Bergara B-14 Wilderness HMR in 6.5 PRC

And for this rifle, I thougth the Athlon Ares 4.5-27x50mm scope would be perfect, here’s my full story covering that optic and the Bergara rifle:

TESTED: Athlon Ares BTR GEN2 4.5-27x50mm Riflescope

The Athlon Ares BTR GEN2 4.5-27x50mm Riflescope offers a first-focal plane design, and illuminated reticle. With a magnification range of 4.5-27mm- I thought this scope would be perfect for both close and long-range hunting.

Load Development Starting Point

I took a look at what burn rate would work for 6.5 PRC, and noticed powders like H-1000 and Retumbo seemed like a good fit:

Well, it turns out that I didn’t have any Retumbo or H-1000 in the shop (although I have some on order!) so I looked at what else could work. I had both Ramshot Magnum and Accurate Magpro on hand, so I decided to try Accurate Magpro for 6.5 PRC!

Fortunately, Western Powders has released 6.5 PRC Load Data that covers both Ramshot Magnum and Accurate Magpro. I used this load data as a starting point to determine which charge weights I would try.

ADG 6.5 PRC Brass from Creedmoor Sports

When I found out that Creedmoor Sports carries 6.5 PRC Brass from ADG, I thought to myself: I’ve got to try some of that! So for all of the load development and testing shown in this article/video, I used ADG factory seconds. Thanks to Creedmoor Sports for helping to get some of this hard-to-find-brass for me! In short, I’m impressed! Read on to find out more.

Load Development Strategy

This time I used a load development strategy similar to what Bryan Litz told me that he uses:

  • Start with a charge weight close to max
  • Load batches of ammo with incremented charge weight
  • Look for the intersection of good accuracy (precision), and low SD/ES on velocity.

I ended up with the following load:

Use load data at your own risk. Ultimate Reloader is not responsible for errors in load data on this website. Always cross-reference load data with manufacturer’s published data.

Loading with the RCBS Rebel Plus Kit

This was my first opportunity to load with the RCBS Rebel Plus kit in the UR Micro Cabin, and it worked GREAT (the equipment and the facility). The only thing I didn’t use from the kit was the scale. Since I’m publishing results formally, I decided to use a lab scale.

A&D FX-120i Lab Scale

I’m now using the A&D FX-120i from Cambridge Environmental (CE Products) for most of my load development and research articles because it has an accuracy of 0.02 grains! Up at the UR Micro Cabin, I run this off a small inverter generator, and it works great.

If you are looking for a serious reloading scale, check it out at CE Products:

Initial Results

It’s amazing what a change of 0.5 grains of powder charge can do to velocity! That’s why load development is so critical. Here’s the best group from my testing (58.0 grains Accurate Magpro, 5 shots, 100 yards, suppressed):

The above group measures 0.275″- very impressive for a factory rifle!

And for this group, the velocity data was as follows:

  • Average velocity: 2940
  • SD: 7.9 fps

I was able to push velocity higher with more powder, but my SD and accuracy suffered. I think this load is just about perfect for this combination.

What’s Next

Now that I have a GREAT SHOOTING match load I’ll start to experiment with hunting bullets (since this is a hunting rifle to me). I’m looking forward to trying different bullet weights and  profiles/construction. Should be a lot of fun! I think I’ll also try Hodgdon Retumbo and Hodgdon H-1000 powders to see how they perform!

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Thanks,
Gavin

8 thoughts on “6.5 PRC Load Development: Bergara Wilderness HMR”

  1. I live in ca and need to hunt with lead free bullets, I would like to see if you would do some loads with the 127gr Barnes lrx bullet in the 6.5 prc

  2. Gavin: you are an incredible resource, I look forward to all of your data, you are professional and comprehensive in development and presentation. Congrats of creating a career for yourself.
    “If it is to be it is up to me“

  3. Hi Gavin. I Bought an HMR Pro in 6.5 PRC this past spring. Been loading a lot of H1000 and IMR8133 With 143g ELDXs on top. I’ve been close to half inch groups with it. Excited to try some Mag Pro. Ordered some today along with some Bergers. I can’t find Retumbo anywhere. I read the ADI Australian plant that makes it burnt down.? Not sure. Have you heard anything about Retumbo and where to find it? Thanks – Andrew

  4. Just wondering why your not using the full auto trickler with scale. Was there a problem or just a need to demonstrate the scale in use with kit components as in thus video?

    I’ve been struggling with my fall to do list but the last time I checked on my scale/auto trickler my phone with the app couldn’t find the scale.

  5. Please try Hornady ELD Match in 147 grain – has an excellent BC.

    Also, you make no mention of jump in your particular gun. Would be nice
    to know what you use. In my custom 6.5 PRC I find that factory ammo – 147 ELD Macth has a jump of about 0.040.

  6. Try the Berger 6.5 mm 156 Grain Extreme Outer Limits (EOL) Elite Hunter, a awesome projectile with great hitting power and expansion, loaded with reloader 26, lapua brass and federal premium primers, sub 1/4 inch groups @ 100 yards

  7. Thanks for your interest in the 6.5 PRC. I’m building a 6.5 PRC also. My local supplier laughed when I inquired about the availability H-1000 & Retumbo. But I was able to get a couple of pounds of R-25 (from Midway) which I hope will work well with the 140 grain hunting and target bullets I’ve finally gotten.
    Brass was almost impossible to find, but finally able to buy 100 rounds from GunWorks, pricy but appear’s to be best quality.
    I finally got 1000 Fed Match primers, interesting they are a couple of thousands too tall, and seat slightly above the head stamp. Got A reamer coming from K&M to increase the primer pocket depth.
    I’m seeing some relatively minor quality control issues in my components, I suspect high demand and Covid are causing manufacture’s the QC issues.

    1. I noticed the federal match large rifle are long Also and seat really hard into ADG brass. I’ll look into that reamer. Thanks for the info. – Andrew

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