TESTED: Accurate MAGPRO Smokeless Powder

I’ve got an elk hunt quickly approaching and need a powerful and flat-shooting magnum. Let’s take a look at what’s a good powder for that!

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About Accurate MAGPRO

MAGPRO is a well-proven powder used in a wide range of intense, high-velocity, overbore cartridges. It is a slow-burning, double base spherical powder that is known to be temperature-sensitive. It is also made in the USA!

From Hodgdon:

Accurate MAGPRO is a slow burning, double-base, spherical rifle powder developed specifically for the Short magnums of both Winchester (WSM) and Remington (SAUM). This powder excels in the 6.5 x 284, 270 WSM and the 7mm WSM. MAGPRO is an excellent choice for belted cartridges such as the 300 Win Mag. Consistent performance can be expected from the excellent metering properties of MAGPRO. Made in the USA.

MAGPRO is available in either 1 lb. or 8 lb. containers.

Burn Rate Analysis

MAGPRO sits between Vihtavuori N170 and Reloader 26, firmly in the group of slow-burning powders well-suited for overbore and magnum cartridges.

As a group, these powders are the best choice for cartridges like the 6.5mm, 7mm, and .30 caliber magnums, whether or not they’re officially called “magnum.”

Most of the popular overbore cartridges will do just fine with MAGPRO and similar powders, but some overbore cartridges with heavy bullets may be better served with something slower. As a spherical powder, MAGPRO is easier to work with than some other slow-burning powders.

Under the Microscope

A close look at MAGPRO revealed two different sizes of dark gray spheres.

(L to R): MAGPRO,H4350, H1000, StaBALL HD

MAGPRO flowed through the RCBS Uniflow manual powder measure very nicely and consistently. I expect it would do well on a progressive as well. I compared MAGPRO to H1000, H4350, and Winchester StaBALL HD.

Our Handloads

Gavin and I loaded 6.5 PRC and 7mm Rem Mag with MAGPRO.

The 7mm Remington Magnum loads were from a 26” Winchester Model 70 Super Grade.
The 6.5 PRC load was from a Bergara B-14 Wilderness HMR with a 24” barrel.

Hodgdon’s online reloading data center showed 74 grains as the maximum charge of MAGPRO with a 139 grain bullet. I loaded 73.5 grains and 74.5 grains of MAGPRO under a 139 grain Hornady CX bullet in new SIG brass for 7mm Rem. Mag.

Though I believe the load can be tuned a bit to tighten the SD numbers, I am very impressed with the near 3300 fps muzzle velocity achieved. (It should be noted that my Winchester Model 70 has a 26” barrel.)

For decades I’ve been a fan of the long and lethal 175 grain hunting bullets for various 7mm magnum cartridges. My favorite powders for it have included H870, RL-22, and IMR 8133— none of which is available anymore. 2900 fps is a good target, but many factory loads achieve far less than that.

I’m pleased with the 2959 fps and the tight 8 fps SD figure. These long bullets have a high ballistic coefficient and retain velocity well. They are also known to penetrate well, even on big bull elk! I had previously assembled the 7mm Remington Magnum using our RCBS Summit press and 1973 vintage RCBS dies.

The Summit press has an interesting design in which the cartridge case is held stationary while the die is lowered and raised. It has a huge, open frontal area in which to work, and is capable of producing very accurate loads. Gavin used the RCBS Rebel press to load for the 6.5 PRC and also produced excellent ammunition on this heavy-duty, single-stage press.

He loaded Berger 140 grain 6.5mm Hybrid Target bullets over 58.0 grains of MAGPRO in new ADG 6.5 PRC brass with CCI BR-2 large rifle match primers.

These handloads produced an excellent .275” five shot group at 100 yards through a factory Bergara B-14 Wilderness HMR in 6.5 PRC.

In addition to great accuracy, this load produced 2940 fps and was not a max load. Higher velocities were observed but accuracy suffered when Gavin increased the powder charge.

Both Gavin and I used the RCBS Uniflow powder measure, a manual powder measure with which I have decades of experience. These newer production models are more nicely finished than my 40-year-old version. The spherical MAGPRO powder flowed very smoothly and easily through the powder measure which threw consistent charges.

Other MAGPRO Cartridges and Loads

Quite a wide variety of cartridges can be successfully loaded with Accurate MAGPRO.

The above info is from Hodgdon’s Online Reloading Data Center.

As a long-time fan of the light-recoiling, accurate and lethal .25-06, I’m very interested in handloading the highly-regarded 100 grain Barnes TTSX to over 3300 fps and using it to pursue mule deer, pronghorn antelope, and black bear.

As long ago as the 1970s I noticed that the 7mm magnums recoiled noticeably less than the .300 Winchester and .300 Weatherby magnums. I’ve always been able to handle the 7mm magnums better than the 30 caliber magnums and have found them more than adequate for North American big game. I’ve taken elk, mule deer and pronghorn antelope with a 7mm Remington Magnum using 160 and 175 grain bullets.

I also watched a hunting partner take a good Alaskan grizzly with a single 140 grain Barnes TSX bullet. With an elk hunt coming up in a couple of months, I’m working on a new 7mm Remington Magnum load and am leaning towards a monolithic 140ish grain bullet at high velocity, which is why I tried MAGPRO with the 139 grain Hornady CX bullets.

I’m happy with the accuracy and on-game performance of the 165 grain Hornady CX bullet from my .30-06. Perhaps I can get even better performance from the higher velocity 7mm Remington Magnum. I am also considering a more traditional jacketed 175 grain bullet.

Mean Point Blank Range

“Mean Point Blank Range” (MPBR) has gone out of fashion in recent years, replaced by either dialing the reticle or using a range compensating reticle. However, MPBR remains effective and practical, particularly with high velocity rifles.

Look at that! About 5” high at 200 yards and only 7.5” low at 400 yards… Hold on hair to 400 and a bit beyond.

Hunting situations can change quickly, and a hunter should be prepared for shots at any reasonable range. It’s convenient to have the zero set so that the hunter can simply “hold on hair” at any range from up close out to approximately 400 yards. The high velocities obtainable with MAGPRO and other slow-burning powders makes for a very flat trajectory, simplifying 400 yard shots. I often use this method with my flat-shooting open-country rifles: the .25-06 and the 7mm Remington Magnum.

Gavin and I may create a more involved video and article comparing and contrasting MPBR with dialing or using a range compensating reticle, but I wanted to at least make mention of it.

Conclusion

Accurate MAGPRO is well- suited for use in overbore cartridges and is capable of fine accuracy, high velocity, and tight SD figures. These qualities make it valuable to the open country hunter with an accurate high velocity rifle. I suspect that it could also do well in long range rifle matches in which high velocity rifles are allowed.

On the downside, MAGPRO is temperature-sensitive. A load developed in cool or cold weather may be over-pressure if used in the heat of summer. The point of impact may also shift with temperature variations. My solution when using temperature-sensitive powders is to limit their use to cooler temps common during the fall and winter hunting seasons. Unlike some newer powders, it does not have any copper fouling reduction properties.