7mm or .308?

[308Nut]

We look forward to the coming weeks when your friend receives his instruments for BC evaluation.

 

Keep us posted!

[308Nut]

We have made a 180 gr 308 bullet that by drop at 400 yds has a 0.65BC. The 170 has a similar profile.

Have you tried time of flight tests or double chronograph tests?

[nralifer]

We have on order 2 acoustic chronographs that have larger detection areas. They seem to be well suited for determining velocity drops over long distances. If we can maintain minute of angle groups we should be able to get data on virtually every shot by placing the chronograph under and slightly in front of the target. Also the chronograph can be protected from a bullet impact since the detection area is above the chronograph, by placing it behind a sand bag. Measuring velocity drops over 300-400 yd should be readily doable.

[jgraffaz]

300/win mag

[billrquimby]

I have written biographies and ghostwritten autobiographies for eleven international big game hunters with more hunting experience than everyone on this forum combined. These men had hunted in 50 or more countries for 250 or more different types of animals. It should go without saying they could afford any rifle made. (One of them paid more than $200,000 for a one-of-a-kind double rifle and never fired it.) Not one of them used a .308 Winchester, but six regularly used 7mm Remington Magnums for game up to the size of moose and eland, and one swears by his 7mm Remington Ultra Magnum. All nine of them at one time had used .300 Weatherby Magnums before the 7RM came out in 1962. Not one of them could be called a gun nut. For example, C.J. McEroy, the founder of Safari Club International, used only four rifles in his lifetime of hunting: a .30-06 Remington pump for his first hunt in Kenya and Tanganyika early in his career, then a .300 Weatherby, a Sako .458 Winchester Magnum, and a 7mm RM. All of his rifles looked as if he used them to pound nails, break brush and roll rocks. I doubt if he had cleaned any of them. -- Bill Quimby

[STOMP442]

So basically these were a bunch of guys that had way to much money for their own good and treated equipment like crap. I don't care who you are or how many animals you have killed with whatever caliber, there is no sense in treating a rifle that way. A rifle is the one thing a true hunter should value most as without it your pretty much screwed on your hunt. It blows my mind when people bring me rifles to work on and claim they don't shoot when they look like they have been dragged behind a truck for a week and full of fouling because they are either to dumb or lazy to take care of their equipment.

[billrquimby]

These were wealthy guys who had become so obsessed with collecting everything that walks that it became a full-time thing with them. They had made six to fourteen major hunts every year for two decades or more on their quests. To them, guns were merely tools, like hammers and shovels. They did not purposely abuse them, but they also did not "baby" them. Their rifles looked like crap because they had been on every conceivable type of airplane and vehicle, as well as on horses, donkeys, camels and yaks, across six continents in every type of weather. Their rifles got more use in two years than an average hunter's rifle gets in two lifetimes. These guys could afford to own 300 different rifles (and a couple of them did), but they each had a favorite and used it on nearly every hunt. In interviewing them for the fourteen books I wrote for those eleven guys, not one mentioned a rifle failing them on a hunt. Equipment failure would not have bothered them as much as it would us, however. They could afford to make as many trips as it took to collect a 15-pound grysbok in Africa or an obscure 500-pound argali subspecies on the roof of the world. My point, though, is that not one of them used a .308 Winchester, and the go-to caliber for everything except large, dangerous game for more than half of them was the 7mm Remington Magnum. Incidentally, I don't know anyone (myself included) who wouldn't like to have too much money for our own good. --- Bill Quimby

[308Nut]

I'm confused when people keep bringing up the 308 Winchester versus the 7mm Rem mag in this thread. I was under the impression that this thread was .308 'caliber' (bore and bullet dimensions) versus 7mm caliber (.284).

 

Maybe I'm off base but...

[STOMP442]

I guess I'm just different because I take care of my hammer and shovels too. There is a difference in using tools and abusing tools.

[ThomC]

This is just a ford/chevy post and I am surprised at all the posters that are confused about what is actually the subject. It is not clear. It could be a ford/toyota post. What bothers me is that a youngster reading these posts would think that to "hunt" one must have a super mag 1000 yard sniper rifle. Do you hunters have statistics that indicate the hold under or over for the curvature of the earth?

 

PS This is the posters first post. inklevr mmmmm wonder what that means.

[roninflag]

270 vs 280 vs 30-06 for maine whitetail. 7.5 vs 8 shot for gambels. , a 28 ga vs a 20 gauge for mearns.. 7mm vs 308? stuff for gunknutts . . A wall for a 100" tusker shoulder mount vs a wall for a 100 " coues ?

[roninflag]

I have read a plethora of reading stating that the .308 is a fantastic all-around caliber for hunting all kinds of game and long range shooting. Recently, an acquaintance of mine that also happens to be a licensed hunt guide, mentioned that he would recommend I purchase a 7mm as opposed to the .308 for an all-around long range rifle. He states that it shoots flatter, has more kinetic energy at longer ranges, and is much faster.

 

Can you coues folks help me determine which caliber is truly superior if I'm looking for a well rounded rifle that can handle long ranges and still be effective? Are the benefits he mentioned actually true, and are they actually benefits?

 

I want something that's going to be able to hunt anything in North America aside from varmit, but I don't want a rifle that is going to be overkill. a sendero in 7mm mag would be a good one. But an all[-around gun? if you can whitetail in vermont and blackaill in Ca and bear In Pa and....... and on and on the hunt and trip are the expensive part . the rifle for a particiular would be a small cost. and usually you sell for 80% of the origianl cost.

[nralifer]

When talking about the the 7mm and 308 bores, one thing to remember, like cubic inches in engines, the bore cross sectional area determines the bullet energy potential, because the amount of accelerating force exerted on the bullet varies as the square of the radius. Thus a 308 bore has grater power potential than a 7mm, which is greater than a 6.5 which is greater than a 6mm. A good illustration of this concept is to compare the 7mm08, 308 Win and 338 Federal. All use the same parent case and almost equivalent powder charges, but a lot more muzzle energy is obtained by the 338 cal bullet (2500 ft-lbs for the 7mm08 vs 3220 ft-lbs approximately for the 338 Fed).

[nralifer]

Got the chronographs, and started playing with them. Takes some practice, but for those of you interested in looking at the Superchrono acoustic chronograph, they are interesting little instruments. Be sure to follow the directions to the T and use them on flat ground. At the muzzle, be sure to put it at least 10-12 feet away to avoid recording the muzzle blast.

 

Anyway, was able to get BC data for a 30cal 180gr bullet that we made from copper bar stock on a Swiss lathe. Conditions were 13 F, 30.16 BAR, and 100% humidity. I used a 300WSM, with 71.1gr Superformance with a muzzle velocity of 3120 fps. The range was 185 yds. The calculated G1 BC from the drop in velocity was 0.62. I was using my hunting rifle with a 1:11 twist 26 in Lilja barrel. Stability factor was 1.12 which is on the ragged edge of stability under the conditions tested, but nevertheless got round holes on the target and the 4 shot group size was 1.3 in. The drop at that distance corresponded with the velocity change. Both indicated a G1 BC of 0.62.

 

For a first try these data are encouraging. I have now a 300WSM barrel with a 1:9 twist mounted on a Savage 110 action that should improve the stability factor to over 1.4 under those conditions. Weather is cold now in South Dakota but with better stability the BC may increase some.

[308Nut]

nra, where can I buy some? I'd like to do an objective evaluation of these.