Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login
Posted: 10/4/2004 12:39:41 PM EST
From October Guns & Ammo

Magnum Magic?

I may have part of the answer to the question of how the short magnums perform as well as traditional magnums while using less powder. The short magnums come in barrel lengths equal to the long magnums, usually 24 inches. However, this number is from breech to muzzle and does not indicate the length of the barrel in which the bullet accelerates down. As a generalized example, a 7mm Remington Mag. is close to a half-inch longer than a 7mmWSM, because it takes up less room in the breech, has an additional half-inch or so of barrel through which to accelerate. This might translate into an extra 30 or 40 fps. This is on top of any additional efficiency provided by the short, fat powder column. Just a thought.


Marc Smith, Huron, SD

I don't think this is right. A 24 inch barrel is a 24 inch barrel. He seems to think that the case has extra room because it is shorter but all cases set snug inside the chamber.
Link Posted: 10/4/2004 12:42:18 PM EST
Barrel length is measured from the breech face to end of barrel. Since the Short Mags have a shorter case length, there is more actual rifled barrel versus that of a regular magnum.
Link Posted: 10/4/2004 12:44:10 PM EST
Barrel length is basically measured from the muzzle to the face of the closed bolt.

Now, if he meant bore length...bore length would be from I would imagine the start of rifling to the end of the muzzle...so theoretically, a shorter case would allow for a longer bore, which theoretically might allow for an extremely slight increase in FPS...so slight as to be negligable.

Just a SWAG..
Link Posted: 10/4/2004 12:44:27 PM EST

Originally Posted By PAEBR332:
Barrel length is measured from the breech face to end of barrel. Since the Short Mags have a shorter case length, there is more actual rifled barrel versus that of a regular magnum.



I still don't follow. That would mean that a .223, .243, 6mm and .308 have a longer trip down the barrel than a .270, 7mm ect.
Link Posted: 10/4/2004 12:47:14 PM EST

Originally Posted By VTHOKIESHOOTER:

Originally Posted By PAEBR332:
Barrel length is measured from the breech face to end of barrel. Since the Short Mags have a shorter case length, there is more actual rifled barrel versus that of a regular magnum.



I still don't follow. That would mean that a .223, .243, 6mm and .308 have a longer trip down the barrel than a .270, 7mm ect.



Yes, because the sit farther back in the barrel due to the shorter case length. The barrel is still the same length though due to the fact that the lebgth of barrel is measured from bolt face to the end of the barrel. I too dont think that it makes much of a difference, if any.
Link Posted: 10/4/2004 12:55:24 PM EST

Originally Posted By killingmachine123:

Originally Posted By VTHOKIESHOOTER:

Originally Posted By PAEBR332:
Barrel length is measured from the breech face to end of barrel. Since the Short Mags have a shorter case length, there is more actual rifled barrel versus that of a regular magnum.



I still don't follow. That would mean that a .223, .243, 6mm and .308 have a longer trip down the barrel than a .270, 7mm ect.



Yes, because the sit farther back in the barrel due to the shorter case length. The barrel is still the same length though due to the fact that the lebgth of barrel is measured from bolt face to the end of the barrel. I too dont think that it makes much of a difference, if any.



So, gun makers leave more extra room on guns that have shorter cases. Is this so that if the owner wants to rechamber it they can have a larger chamber drilled in? Seems like a waste to me.
Top Top