Choosing a Long Range Hunting Load

Choosing a suitable long range hunting load can take time. It might also require a certain amount of perseverance. This installment on the 300 Winchester Magnum Project will cover how I narrowed down a load for it.

I know this article is somewhat late in coming, but I’ve been busy shooting the rifle to prepare for Idaho’s spring bear season. As of today, the total round count down the barrel is 277. Jake and I have validated drops to 1682 yards, with a lot of shooting in the 600-1000 yard bracket where I intend to use it the most. In Initial Load Development: 300 Winchester Magnum Project, I outlined my process for building a rough draft of the final product. I also mentioned what I look for when developing a long range hunting load for a precision rifle. Here are some of the considerations:

• The accuracy of the load must be high enough to give me total confidence in first-round hits at the furthest distance I plan to hunt with it.
• The bullet has to retain velocity to that distance to allow it to quickly kill the animal.
• The velocity Extreme Spread (ES) must be low enough to ensure low vertical dispersion at distance.
• The load has to be easy to duplicate, with no finicky procedures or voodoo involved.

It wasn’t easy to narrow down the final recipe for this rifle. During the initial load development I had quite a few combinations that worked pretty well, but none that really stood out. I decided to focus on Berger bullets to help simplify the process. I’ve had great luck with their .264 caliber bullets for long range hunting, never wanting for more accuracy or lethality. I stuck with H1000 for the powder, CCI 250s for the primers, and the original batch of 97 pieces of Winchester brass. In case you missed how I prepped the brass for this project, you can read about it here.

Three-shot group at 100 yards with the Berger 210 grain HVLD.

Accuracy improved dramatically once all of the brass had been fired, annealed, and sized properly.

It’s been my experience that custom barrels usually shoot well right away, whether the brass is new or fired to fit the chamber. This rifle shot pretty well with new cases, but once I started using once-fired brass I was hard pressed to find a load that shot worse than ½ MOA. Accuracy rose dramatically and velocity extreme spreads fell to acceptable levels. Life was good.

What had changed? I think the single most important thing is the brass now fit this chamber. I always measure new brass and note it at the beginning of a project, so I had some good data. Measuring from the datum line on the shoulder to the case head with a Sinclair comparator, new cases measured 2.206”. With one firing, cases measured 2.221”. I compared notes with data from several other rifles, finding only one other chamber that had that much brass growth. I suspect most of it had to do with the shoulder angle and total overall length of the new brass changing to conform to the chamber. A belted magnum case is designed to headspace off the belt, unlike a conventional bottleneck cartridge that headspaces at the shoulder. As part of an experiment, I’m working in another 50-count bag of brass to the project. I prepped this brass the same as the original 100 pieces, but also turned the necks down to have no more than .001” thickness variation. After firing these cases, it was easy to see where the brass grew. If you look at the photo below, you can see where the neck sealed when the case fired, and the portion of the shoulder that moved forward. It definitely makes the case for turning necks after firing them at least once.

Distinct ring of brass movement showed up after first firing.

The case diameter also changed significantly. Measuring just below the belt, the case expanded by .007”, and the diameter just above the shoulder grew by .005”. What does all of this mean? I don’t know, other than I suspect it was a brass thing, not a chamber thing. We’ll come back to that later.

Annealing with a Bench Source machine.

Between the first and second firings and before full-length sizing the brass, I annealed the cases.

Opinions vary concerning the merits of annealing as well as the best way to go about it. I never felt the need to anneal brass until I started using Winchester brass for my 7WSM DE Stalker. It was fairly obvious after the third firing that the elasticity of that brass was changing as it was fired, sized, and fired again. Neck dimensions were inconsistent after sizing, and I could feel the difference in bullet seating pressure through the press handle. Load precision at 100 yards didn’t change, but vertical dispersion at long range definitely increased. Annealing that 7WSM brass brought the velocity extreme spread back down and increased the long range accuracy of the load.

I use a Bench Source annealing machine. I’ve tried a couple of the more popular methods that don’t use the automation of a machine, and never felt great about the results. The whole point of annealing is to heat up each case neck to a specific temperature—get them too hot and you ruin them, fail to get them hot enough and you don’t gain anything. For annealing to occur, the case neck and shoulder junction needs to reach ~ 750° F. A lot of the methods shown on YouTube have you turning the lights down and heating the brass to a certain color. I’ve found that brass color is not a reliable indicator and usually if it turns any shade of red, you’ve gone too far. There’s a temperature sensitive paint called Tempilaq that you brush onto a case before you heat it up. Available in a wide range of temperatures, it changes color when the surface it’s on reaches the temperature it’s rated for.

Following the directions that are provided with the Bench Source machine, I paint a short, thin strip of 650° Tempilaq directly below the shoulder junction. They say that the Tempilaq turns clear when the correct temperature is reached, but I think a more accurate description is that it turns a burnt black color. Either way, it changes color at a certain point, and that’s when the case needs to come off the heat. The reasoning behind using 650° paint below the flame instead of 750° paint at the flame is that heat will transfer better below the shoulder than at the neck, resulting in a higher temperature right at the flame point on the neck/ shoulder junction. If you expose Tempilaq to direct flame, it turns color instantly. I’ve had perfect results using this method, and with the machine all of the cases get heated exactly the same. Precise results for precision ammo!

Even with a machine, there are a lot of variables involved for getting the brass to the correct temperature: brass thickness and composition, flame temperature and distance from the brass, and time in the flame all influence the results. Make sure you experiment with it and keep good notes on what worked for you.

650° Tempilaq on a 300WM case.

Properly annealed 300WM cases.

Hornady One-Shot Case Lube.

Once the cases were fired, I full-length sized them with Redding Competition dies.

The first requirement of any long range hunting load is it has to feed reliably and go bang when you need it to. There is no compelling reason to not full-length size brass for a precision rifle. Precision and consistency aren’t affected by full-length sizing in any measurable way and reliability is assured. Using a Redding body die and Hornady One-Shot Case Lube, I sized the brass and bumped the shoulder back .001”. The web diameter was decreased by .001” after sizing. That dimension told me that the chamber was sized properly and the brass, when new, was undersized. That amount of sizing is normal according to notes I’ve kept on my other rifles. That small amount of case sizing, along with the elasticity of the case causing it to spring back after firing can make a big difference if feeding into a wet or dirty chamber. If done properly, case life is not affected by full-length sizing. I full-length size everything I load for, every time. Now the cases are formed to headspace at the shoulder, rather than the belt.

After sizing the case body, I rotated the Redding T-7 press and sized the neck diameter to .333” with a Redding Competition Neck Bushing die. I use the steel bushings and set the die to size as much neck as possible. That diameter gives me .0015” of neck “grip” on the bullet. It seems to be working well. A sample of sized cases were checked for concentricity.

I’ve also had good luck with Redding’s full-length bushing dies. I just received one for the 300 WM and will be running an experiment to see if there’s any difference in ammo quality between the Competition dies and the regular FL bushing die. I’m betting there won’t be.

A sampling of cases were checked for concentricity. Coming out of the body die, runout was “0”. After neck sizing, runout averaged .002”. Why? I don’t know, but I don’t care either. Runout is another variable I’ve tested for affecting ammunition performance. Even with large sample sizes, I’ve never been able to prove that I should worry about it. That includes barrels with short and long bullet jumps. I suspect a good barrel is the most important factor here.

After final sizing, I trimmed the cases to 2.610”, chamfered the necks, and primed the cases with CCI 250s from my RCBS Automatic Bench Priming Tool. Look for a review on the bench primer soon. I really like it!

Hodgdon’s H1000 continues to be my powder of choice for the 300 Winchester Magnum.

Classified as one of their Extreme powders, H1000 has proven to me to be insensitive to a wide range of temperatures. I’ve tested this powder in a few other chamberings and always found it to maintain close velocity spreads whether I’m deer hunting in November or varmint hunting in July. It flat out works. I’m using an Xtreme Hardcore Gear powder funnel to pour charges. Manufactured in Lewiston, Idaho, they are like no other powder funnel. CNC-machined from aluminum bar stock, they are caliber-specific and stay put on the case while pouring. I also own the .264, .284, and .338 funnels, and have never had one jam with powder or spill at the case mouth. It’s a great design. You can check them out here.

Xtreme Hardcore Gear .308 powder funnel.

This funnel stays put on the case!

When choosing a long range hunting load, the bullet is arguably the most important consideration. My final load will use the Berger Bullets 210 grain Hunting VLD. This bullet shot consistently well over a broad powder charge range, with velocity reaching 2930 fps in this rifle.

This bullet proved easy to get shooting well. It also met all of the previously mentioned things to consider when choosing a long range hunting load. Seating it at .010” off the lands (which is my standard starting depth, and one that has proven to work with several rifles) the Berger 210 grain Hunting VLD immediately shot better than any of the previously tried bullets. I fired seven consecutive three-shot groups at 100 yards that averaged .380” with the 210 grain VLD, using several different charge weights of H1000.

Starting at 75.0 grains of H1000, I increased the charge in ½ grain increments until I reached light ejector marks at 78.0 grains. At no time did I notice bolt lift resistance or any other high pressure signs. At 78.0 grains, my MagnetoSpeed chronograph told me the 210s were spitting out at 2930 fps. I backed off to 77.5 grains of H1000 and loaded twenty of them for long range testing. The load held its accuracy at distance, with groups measuring less than .5 MOA shot at 550 and 790 yards. That’s what I was looking for!

Could I have tuned that load for better precision? Perhaps, but this is a precision rifle designed for long range hunting, being shot from field positions in variable conditions. I doubt I could realize any measurable improvements even if they were there.

As usual, all load data was well documented in my load book. With a muzzle velocity of 2900 fps, Jake and I validated trajectories to 1682 yards. For a look at some of those shots, check out this video. Since then, we have fired 34 rounds at distances from 640 to 1277 yards with this load. It has proven to be consistent and repeatable, giving me complete confidence in hunting with it. Time will tell how the 210 grain HVLD will work on animals at distance, but previous experience tells me the Berger HVLD is a reliable bullet for a long range hunting load.

As I finish typing this article, my gear and the 300 WM are sitting in a pile next to me, ready to go get some long range practice in. Choosing how to build a long range hunting load should allow you to shoot more and load less. In my experience, variable conditions will always thwart your best attempts to tweak a load into a slightly more accurate one. My ability to read those conditions on any given day requires me to shoot a lot. In order to do that, I need to have a process that allows me to feed the beast in a timely, consistent manner. I’m always looking for ways to streamline that process, but what I’ve outlined above works very well for me. See you next time!