I was out at the range today with my chronograph. A nice guy next to me was shooting a new 300 WSM, getting ready for a moose hunt. I invited him to shoot over my chrony as I was curious as to how the 300 WSM prints. A two shot average was about 2870 FPS using 180 gr Federal Premiums.

A little later another shooter wanders over inquiring as to the test results of the 300 WSM. I told him 2870, and he promptly started complaining about the "short mag hype". I sort of agreed saying whats old is new again as I was shooting a 300 H&H today and my moderate loads were a just a tad slower than the WSM.

His reply was, "Hell, that's no better than a 30-06." Then he continued on telling me to look into a 7 Mag to get some "real flat shootin".

I invited him to bring his 7 Rem Mag over for a demo. He was shooting a box of 140 gr Remington Core-lokt Ultras out of a stock 700 BDL. A three shot average was 2920 fps.

He thanked me for cluing him in that he had a box of bad bullets and said that he'd go back to his regular loads.

Ballistics tables are generally optimistic, but the 7 Mag is the one cartridge that seems to most often disappoint its owner when shot over a chrony.

You're right on that. I get 3175 (chrony'd) out of my 280 Ackley with the 140 grain XLCBT. There is nothing wrong with the 7 mag, but my choice is the Ackley.

I had a Savage 270 WSM that did 3223 fps with the factory 150 gr Power Points. That's a little better than the 270 Weatherby's published ballstics.

The bolt would open with effort. Now that's a hot load.

On another forum a writer by the name of Barnsess say's that the 7mm RM is downloaded due to extreme pressure spikes.

I have no problem getting 3250 with moderate 140gr loads in 7mm RM. 160gr Partitions at 2950. These are chrono'd speeds. Factory stuff in heald way back.

The old Speer #8 reloading manual has a couple of tables showing chronoed factory loads of the day in actual sporting rifles .



At that time , 7mm mag Remington factory loads came out just about right where they should have been , considering barrel length, at 2990 fps for the 175 gr corelocks and 3135 fps for the 150 gr core locks . This in a 24 inch M-700 barrel .



I like Barsness , but he has always had a bit of anti 7mm mag bias and it shows in his writings. I take the claims about 7mm mag spiking pressures with a grain of salt......

The 7 mag is downloaded in factory rounds but not near what your chrono showed. That 140 load should have been considerably faster.

W/ Remington Factory 150s, I get over 3100 fps out of a Model 700 (factory 24" tube).

When handloading I can get over 3300 w/ 140s, over 3200 w/ 150s, and over 3100 w/ 160s. These loads show absolutly no signs of pressure and shoot sub moa.

The 7mm Remington Mag is indeed a very Flat, Hard hitting big game cart. As w/ most cart. it takes some tinkering to achieve the optimum performance level.

Good Luck!

Reloader

I have allways thought the 7 mag was a very good cartridge, but only a little hotter than my hand loaded 24 inch 30,06. The first rifle in my collection was a 30,06 and I was concidering a rifle for longer range, I ended up picking a 7mm STW. I think it IS what most most people THINK the 7mag is...tj3006

You mean to say you can buy ammo already rolled? What's this country coming to?

No problems with kicking 140 gr. TSX's to 3300 fps yesterday, I'm happy to report. As a matter of fact, the load was 4 fps from Alliants listed data for the combination of components I used!

Sounds like the thread should be re-named "factory loads and chronographs don't mix". JMO, Dutch.

The 7mm Remington Magnum is one of the cartridges that has been "wimp-ized" these days, at least as far as current handloading data is concerned. I have no idea how current factory ammo performs, because I don't use it, nor have I ever chronographed any of it. However, my old 140-grain Nosler Partition load, which I have been using since I got my Ruger 1B in 7mm Rem. Mag. back in 1969, gives an average (chronographed) MV of 3375 FPS, and my 175-grain Nosler Partition load gives over 3050 FPS @ 10' from the muzzle. I see no particular point in dragging around a heavy, long-barreled 7 Mag. and shoot ammo in it that gives 7X57mm performance, when you could use a nice, light Ruger 1A in 7X57mm and get the same performance burning 10 grains less powder to do it!!

Since the 7mm Rem. Mag. has almost exactly the same case capacity as the 7mm Weatherby, there's no reason at all why it can't perform up to the same level ballistically. Yes, the Weatherby does have a freebore. But in this comparison, all that fact means is that the Weatherby needs more powder than the 7 Rem. to produce equal velocities. Both of them can outperform both the 7X57mm and the .280 Rem. with perfectly safe loads! If they couldn't, there would be no point in using them, and if the various .300 Magnums can't outperform the .30/'06, however slightly the margin might be, there'd be no point in using them, either!!

I too have much regard for Barsness, but the 7Mag pressure explaination almost defines the pressure "excursions" as having to do with some "magical" dimensions of the case and bullet rather than logic. If one looks at the design of many "overbored" cases that wear a belt you could make a case that the .257 Weatherby Mag or any number of belted "hot rods" are subject to the same excursions. Could it be that they don't have the problem because they have a "venturi" shoulder, longer neck, greater capacity, less capacity, loaded with different powder, harder bullet, or softer bullet, etc., etc., etc. In other words, there are so many variables that it is amazing that a general statement about one cartridge is true without having any bearing on any other cartidges. Could it be, as Rick Jamison suggests, that when you reload close to max that you have negated the safety factor of what contitutes the acceptable maximum pressure, ie. if 61000psi is maximum, and your powder load is maximum how do you know that your average load is around 61000 without going over by 3000 or 10000. And, are all your cases new or once fired so they will give you near the same indications of high pressure. We know the hardness of the bullet jacket has a great effect on the pressure because we can see the effect over the chronograph, but do we know if one bullet has a tendency to cause pressure excursions? Or, do we normally shoot "soft" bullets that have little effect on pressure? How about boattail bullets versus flat base (I usually get a little bit more velocity out of the flat base, but it could be seating depth). Anyway, I too have a 7Mag in a Weatherby Vanguard Classic II and a friend who has the same caliber in a Model 70 Winchester. His uses less powder to reach the same velocities over my PACT chronograph. I was a bit disapointed because I did not expect to have a "sloppy" chambered rifle shot so "slow". However, I have not experienced any different pressure excursions (spikes) that differed from the other 19 calibers I have reloaded when loading near max velocities. Many times my max loads were only as high as that published when I used the max load of the slowest burning powder, eg. 80gr H870 with a 160gr bullet or 66gr. IMR7828 with a 175gr bullet. The faster burning the powder used the greater the difference I found in the recorded velocity from that published. One reason I have kept this particular rifle has nothing to do with caliber; for it is exceptionally accurate with just about any load I put in it from the 7x57 level to full 7 Weatherby Mag level. Like most users I prefer to load the 160gr bullets to 3000-3100 and the 175gr bullets to 2800-2900 and use my 270Win with lighter bullets instead of subjecting myself to the extra blast of the 7Mag (or the extra gun weight). Until someone, maybe a ballistics lab, can tell us why this one "special" case causes pressure variations that exceed all others, I'll stick with the max loads published and watch for all the pressure signs devined by the loading manuals, "gun loonies" (Barsness, Simpson, et.al) and keep good records. I appreciate the great information on this site.

It may not be the loads but I think many of today's factory rifles have "generous" chambers. Couple that with cautious load data and many are surprised at the actual velocity they're getting. For instance, I have a Remington 7 in .308 that I've been doing load development on for 165 grain bullets and IMR4064. One loading manual states the maximum at 42.7 grains others go as high as 45.0. In my rifle, 42.5 produced an average velocity of 2280. 2280! that's .30-30 territory. So far I've gone to 47.0 grains and am getting an average of 2591. Better but still a bit more to go and 2 full grains over the never exceede number. On the other hand, I have a 6.5TCU contender barrel that maxes with pressure signs and velocity a full 2 grains before max. I'd say the Remington has a chamber fatter than me. Chronographs can tell you a lot but sometime it's not what you want to hear.

Yeah! As Bob Hagel wrote in his book on hunting loads and practical ballistics for American hunters, what is maximum in one rifle may be way over, or way under, a maximum load in the next one! That's why the old adage "never exceed a published maximum load" is so damn ludicrous!!