In need of some basics

[Picknlittle]

I need some clarification. I'm not entirely sure this is the proper forum to mention it in, but here goes.

I need to understand the basic differences between standard .30+ cal. rifles and magnum rifles. What makes one gun stronger than the next?

This question comes about as a result of an ongoing discussion about my 35 Whelen. My whelen is a converted 1903A3 Springfield for all intents. The only Springfield component left is the bolt assy.

The Stock is custom. The barrel is a very heavy chunk that measures 3/4 inches diameter at the muzzle. The trigger assy. is aftermarket as well.

Now when I read about signs of overpressure when building loads, the case is the focal point. Primer hole conditions, heavy bolt lift, visible stress marks, etc,...

When I look at heavier cal. and magnum guns, I don't really see anything structurally all that different. I need to to come to grips with this.

Any help out there?

 

[pre'64 Dan]

all magnum means is 'larger', or something close. i never looked it up. a magnum of champagne is the big bottle they drink after a race. case design and receiver construction, along with barrel length are all major factors in considering 'magnums'. just because it's a magnum not mean better. Efficency is my detemining factor whether or not i have a magnum. I say a 'magnum load' vs. a 'non magnum' load of the same caliber is a legit comparison. If I haven't confused you enough, there is always Webster's....Dan:banghead:

 

[Picknlittle]

Okay,...stay within a caliber. 7mm vs. 7mm mag. What makes the mag handle higher pressures, therefore higher velocities.

Also,...I understand that for the sake of accuracy, sometimes pressures need to be lowered. Why doesn't a magnum 7mm suffer in accuracy when it normally operates at higher pressures than a std. 7mm?

 

[Jim K]

Back around 100 years ago, an English company, Holland and Holland, put out some large cartridges with heavy powder charges, and used the name "magnum" (Latin for "large") derived from the term for a large bottle of wine or champagne. The cartridges were primarily for hunting in Africa and India and other parts of the vast British Empire.

One characteristic of those cartridges was the use of a thick belt at the back for strength and to provide case support (headspacing) in place of the common rim. Today, dozens of cartridges have been called "magnum" even though some are not much more powerful than other cartridges without the magic term. Size isn't even a factor; we have a .22 Magnum Rimfire that is more powerful than the .22 Long Rifle, but is hardly going to compete with a .460 Weatherby Magnum.

In center fire rifle loads, though, a magnum cartridge generally has the magnum belt, and that sets the "magnum" class apart from "ordinary" cartridges.

What makes one gun stronger than the next? The locking system and the quality of the material. Usually, a rifle is designed around a cartridge or a group of cartridges. Engineers and metallurgists determine how strong the rifle has to be to safely handle the highest pressure cartridge for which it will be made. Other factors are size and weight. Obviously, a rifle weighing 100 pounds would handle about any cartridge, but not many hunters would want to carry it, so any rifle is somewhat of a compromise among many factors.

Jim

 

[Jim K]

Sorry, forgot the other questions. FWIW, I think the barrel on your rifle, at .750" at the muzzle, is probably a lot heavier than needed for the .35 Whelen. The .35 Whelen, while a larger caliber, operates at the same pressure level as the .30-'06 that rifle was made for, so there should be no problem. The M1903A3 is a very strong action.

My recommendation for reloading is to get a reloading manual and stick to the loads listed. Experienced reloaders can extrapolate at times, but sometimes trying to produce "hot" loads can be dangerous, even with good brass in a good rifle.

Work up to, and don't exceed, maximum levels. The case is the focal point, as it is the case that really has to contain that pressure. The signs of high pressure you mention are warnings to the reloader to back off and drop the loads to a more reasonable level.

Jim

 

[jpcampbell]

Used to be bigger case more powder, mag primmer, same weight bullet faster velocity. now with better powder we use shorter cases and go back to shorter cases. Mag are just more powerful. like 38 sp. & 357 mag.

 

[Chawbaccer]

Jim is right on. Magnum is mostly a marketing ploy. Roy Wetherby put belts on everything, wheather it was needed or not. The case is what primarily determines how much pressure can be generated. Reloading manuals give the SAMMI pressure of each case. It is easier for the firearm manufacturer to make one basic action that will hold up to higher pressures than it is to taylor each action to the pressure range of each cartridge.

 

[Picknlittle]

I don't have any reloading manuals,...so what is the SAMMI pressure for 30-06 and 35 Whelen?