if the 404 Jeffery case was the parent case for the .300 RUM how is it possible that the two case differ from each other..???
The RUM cases (7mm,300,338,375) are basically 404 cases with the following adjustments: The sides are straightened and a sharp shoulder is added, then they are necked to the various diameters. The 338 is also shortened a bit. But then the manufacturing aspect got in- the rim was turned down from .55" to .532" so that the case would fit existing bolt face dimensions for standard magnums. As such, the RUM cases have a slightly rebated rim. There is a slight difference in the case body but it is insufficient to cause a problem with forming one from the other.
Keep in mind gentleman, you do not have a sledge attached to your 404 Jeffery when hunting Dangerous Game animals , all shooting is done 0ff-hand , on the run towards the elephant you just shot or away from the elephant you just wounded..mind you on the worst case scenario you probably will not out run an angry bull Elephant you wounded..your PH with his 505 Gibbs might just be around to save your hide being poke through with elephant tusk holes in it...here is a good compilation of what you are expect to do with your newly acquired dangerous game rifle ...in this video you will noticed a reference to the cost of ammo for a dangerous game hunting rifle .. the costs to practice /shoot your dangerous game rifle is measured in a very except-able currency...a bottle good Scottish Gin per round fire from a 505 Gibbs...Shootist, by the time the barrel kicks up, the bullet is way downrange already. No effect if the barrel kicks up
John, yes, I agree it was a privilege to participate in the dangerous game hunting course with him.Dr. Kevin Robertson is one of a kind, he came from the golden years , when there were Rangers with accumulated real hunting experiences and knowledge of the bush and bush-craft...many of the Special forces members became Game Rangers or Professional Hunters after the conflict in Southern Africa ...a person like Richard Harland , Ron Thompson and a many other great Game rangers /hunters put pen to paper to leave us a rich legacy of written work we of today can enjoy reading and imagine how it really was....I have to give heads up for those who followed in their footsteps , indeed very large boots to fill.....but today Game Rangers with the likes of Piet Nel and Gawie Lindeque as well as a lot of other young men really are taking up the challenge to preserve the natural environment with all species for us and our children still to come when we moved on....I really have a boundless admiration for those who pick up the flag and move forward as well as unimaginable gratitude for the Richard Harlands, Kevin Robertsons as well as the Ron Thompsons we got to know of through their written work and a few of us had the privileged to met along the way..I salute you all GentlemanThanks for sharing Gert, nice to see Doctari at work.
Why bother inventing things like muzzle breaks for people who cannot handle or do not like recoil? The gases that would propel the gun backwards (like a rocket) are lead out sideways or backwards, thereby drastically reducing recoil. Shooting offhand would be a highly inaccurate practice, which it is not. (just watch Olympic shooting disciplines). If it was, I would be dead twice over already as I had to shoot myself out of deep shit.Ray, you might want to sharpen up on your physics a bit. See below:
Although guns may not be everyday things for many of us, gun recoil is certainly something we're aware of (at least those of us that don't make Hollywood action films with guns whose recoil would instantly kill the person firing them!). Gun recoil is a result of momentum conservation, which is an extremely important fundamental principle. Newton was talking about momentum conservation when he wrote "every action has an equal and opposite reaction".
Momentum characterizes an object's resistance to change in motion. If this is motion along a straight line, we call it linear momentum; if it is rotational motion we call it angular momentum. The basic idea is the same: moving things like to keep moving, and to change their motion we have to apply a force. If no force is present, then momentum doesn't change, ie. it is conserved.
Now, you might point out that a bullet coming out of a gun has a huge force on it from the exploding gunpowder. True enough, and that force is what propels the bullet forward. However, if you look at a bullet and gun together (say while the bullet is still in the barrel but already heading out at full speed), you can say there is no net force on the bullet-gun system. So the momentum of the bullet plus gun should be conserved.
If the bullet has mass mb and speed vb out of the gun, it has momentum pb given simply by
pb = mbvb
in the forward direction. To balance this momentum (and keep the net momentum of the bullet-gun system zero), the gun recoils with momentum in the opposite direction: pg = -pb, or
mgvg = -mbvb
Although the bullet's mass is small, its speed is quite large, so it released with large momentum. The gun has much larger mass, so the recoil speed is much smaller, but still large enough to give a serious kick against the shooter's shoulder.
Example: Winchester .308
Let's look at an example. A Winchester .308 cartridge launches a bullet of mass 150 grains (1 grain = 64.8 mg) with a speed of 2820 ft/s (1 ft = 30.5 cm). In MKS units, then, pb = 8.4 kg m/s. This rifle has a weight of about 8 lbs, or a mass of mg = 3.8 kg. That means the recoil speed of the rifle will be
vg = - pb/mg = -2.2 m/s
This primary recoil is noticeable, but not the main recoil that one feels.
There are actually two distinct recoils from a gun: the first, primary recoil, which I've described above, conserves momentum of the gun-bullet system. However, a larger secondary recoil comes slightly later, when the bullet leaves the muzzle: then the hot expanding gas behind the bullet shoots out of the muzzle, and the muzzle recoils further like a rocket. This is, again, conservation of momentum, but in this case is is the gas momentum out of the barrel that makes the secondary recoil. Gun manufacturers make baffles that reduce the flow of gas out of the muzzle to reduce secondary recoil. Primary recoil cannot be reduced, since it is simply associated with the forward momentum of the bullet.
- linear momentum: p = mv
When I go to the range for load development, I shoot over a sand filled Xbag with my right hand (trigger hand) on the grip and my left hand supporting the butt just forward of my shoulder - with ALL my rifles, including the 404. Nothing but the Xbag supports the front of the rifle which is allowed to go wherever it wants to during the recoil. The attached picture is a 100 meter 3 shot grouping out of my .375 H&H. I think repeatability is not a concern - you should try it sometime View attachment 344747
- The total momentum of a system is conserved if there are no outside forces acting on it.
- Gun recoil results from conservation of total momentum of the bullet-gun system: the backward recoil gun momentum balances the forward bullet momentum to maintain zero total momentum.
- Gun recoil actually has two parts: primary recoil from the escaping bullet and secondary recoil from the escaping gas behind the bullet.
That is not correct. the rifle moved during the closed system portion of the recoil. The movement can be calculated by determining the balance point of the rifle with cartridge in chamber and the different balance point with the bullet at the muzzle with the powder distributed between the cartridge web and bullet base. That distance is the recoil prior to the bullets exit and is why rifle position, body alignment, muscle effort as well as rifle support/recoil direction are so crucial to repeatable accuracy.
Congratulations Uwe!!! If Don Rickles were around he'd give you a Brownie Button. Too bad you are answering the wrong question.