18 August 2004, 05:23
MacD37Re: When is it not Controlled Feed ?
Quote:
I know there are a lot of Controlled Feed fans on this Board, so I have a question for you all:
On a Dangerous Game Rifle, how far is it allowable for the bolt move forward "without controlling the cartridge" before it is considered unfit for use on Dangerous Game and time to go to the GunSmith and get the Feed Rails adjusted? 1/4"? 1/2"? 1"? 2"?
HOT CORE, a push feed cannot be made into a CRF by adjusting the feed rails! The CRF, and PF are two distinct, and seperate systems!
A CRF system has control of the cartridge from the time it leaves the magazine! The rim of the cartridge slides under the extractor as it rises out out of the magazine, and has control of the cartridge from that time till it is ejected from the rifle, whether it is chambered, or fired or not! A push feed simply, as the name implies, simply pushes the free cartridge along in front of the bolt, till it is chambered, and the bolt handle turned down. Then, and only then, does the extractor snap over the rim of the cartridge. The actual ejection is accomplished, in the push feed, by a spring loaded pin in the face of the bolt, that only puts pressure on one side of the case, and as the mouth of the case clears the breech, it is supposidly ejected.
Look at the cartridge as you close the bolt on your rifle! If the case rim slides under the extractor as it is pushed forward, and if it is CRF, it should hold that cartridge no matter which way you push or pull the bolt! If, once the cartridge clears the magazine, you continue forward with the bolt it will chamber the round, but if you pull it back without chambering the round,the CRF will eject the round. This isn't the case with a push feed, if you pull the bolt back on it, without chambering the round, it will leave the round loose in the loading tray, and not eject it, then when you push the bolt forward again it will strip another round off the top of the magazine, now you have two cartridges in the loading tray, both vieing for the same chamber! That ain't good. The above is what is meant by SHORT SHIFTING, not the popular belief the a short shift is not pulling the bolt all the way back after fireing to eject the empty. The true SHORT SHIFT is caused by being in too big a hurry to get off another shot under very tense conditions! This is fireing a shot at your target, and then bolting the empty out of the rifle, but when the bolt is shoved forward, for the second shot, the mind is already telling you to shoot the THIRD SHOT, and you draw the bolt back without chambering the second round. If this happens with a CRF rifle the loaded round will be ejected,so the next round has a free chamber to enter! If with a push feed it will not be ejected, and will still be in the rifle, when the next round is striped off the magazine! 
If you think your mind can't play tricks on you,under pressure of, a once shot Buffalo heading your way, think again! The CRF system is simply a system to takes the idiot out of the equasion! All Bolt action rifle today, are basicly a Mauser action, but because they are cheaper to make, some have chosen to modify the origenal, by makeing them push feed, dropping the best feature of the MAUSER action. This is not an improvement, but simply a cheaper way to manufacture the action, and the only improvement is to the maker's bottom line, not to help the buyer! 
18 August 2004, 03:06
Hot CoreI know there are a lot of Controlled Feed fans on this Board, so I have a question for you all:
On a Dangerous Game Rifle, how far is it allowable for the bolt move forward "without controlling the cartridge" before it is considered unfit for use on Dangerous Game and time to go to the GunSmith and get the Feed Rails adjusted? 1/4"? 1/2"? 1"? 2"?
18 August 2004, 05:47
GeorgeSHotcore,
The premise of CRF is designed to ensure that a new round cannot be fed before the previous round has been extracted
and ejected.
By beginning your discussion with an empty chamber, you're missing half the equation.
George
18 August 2004, 07:32
KurtCHot Core,
Good question. A lot of it depends on the cartridge. Some snap under the claw with very little movement, some don't snap under until the bolt is pretty far forward.
With a proper CRF, the round is always controlled by opposing forces, even if it snaps under the claw late in the bolt travel.
There are 2 important things:
1. The cartridge cannot fall out of the action.
2. You cannot strip another cartridge from the magazine if you pull the bolt back before the prior cartridge slips under the claw. Regardless of how far forward the 1st cartridge is still being held by the magazine lips, the next cartridge should still be below the reach of the bolt face. Much of this depends on proper magazine and follower dimensions for that particular cartridge.
18 August 2004, 14:32
KurtCControlled feed means that the cartridge is controlled at all times, be it by magazine, feed rails, follower, extractor, bolt face or chamber wall. As long as it is controlled from the instant you load the cartridge into the magazine, up until it strikes the ejector, it is controlled feed. The cartridge will always be controlled by at least two surfaces exerting opposite pressure.
Under these circumstances you should never have a loose cartidge or a double feed. If you do, than something is out of adjustment. While it is nice to see a cartridge snap under the claw with only an inch of bolt travel, it is not always possible. Some cartridges will have to be pushed a bit further, often until the bullet touches the ramp.
If you ever want to see CRF perfected, look closely as you feed a cartridge through an original (1903-1969) Mannlicher-Schoenauer. It will bring a tear to your eye.
Post Script
I just checked a few of my 98's in standard size cartridges (2 @ 8x60, 2 @ 7x64). The cartridge leaves the control of rails at the half way point of bolt travel, slipping under the claw. If I pull the bolt back before that, the first cartridge is still held in place by the rails and ramp, while the second cartridge is too low for the boltface to engage it. Perfect.
18 August 2004, 16:59
SouthpawMacD37,
Just a few points for fun. Lord know's I've had my oversights corrected here.
I believe you mean Short Stroking. Short Shifting is a common phrase in trucking and refers to either clutchless shifting or skipping a gear. The latter is done when the truck is not carrying a load; therefore, going from 1st to 3rd, 5th, etc. is less effort than working through the entire range.
I was always under the impression that the "short stroking" was the sole domain of the CRF and it refers to the instance when the bolt was not taken back far enough for the mechanical ejector (usually a fixed blade operating through a slot in the bolt face) to "punch out" the empty case. Since the bolt doesn't come all the way back, the empty is not ejected, and the Mighty Claw extractor doesn't let it go anywhere. When the bolt is slammed forward, and the trigger pulled, the dreaded "click" is heard. That is "Short Stroking" The source of the name is the cause of the problem. It is not easy to do this, but when you're life's on the line, breathing can be difficult too.
The push feed actions can also be "short stroked" but with different attributes. In the PF action a "plunger style" ejector is pushing the case toward the ejection port, and only the extractor and the chamber are holding the case in a line with the bore. As soon as the mouth of an empty case clears the ejection port it "springs" out. However, if the bolt is not drawn all the way back, a new round will not be stripped from the magazine, thus the bolt is closed on an empty chamber, and that dreaded "click" is heard.
I believe the circumstance you attributed to the PF action is called a "double feed", and is indeed easy to do just as you state. However, it is a rare occurence that a hunter is under stress during the initial loading. The initial round is usually loaded in a very slow, exacting and quiet manner. Yes, people have cycled every round out of a magazine, without pulling the trigger, but this is no fault of the action design.
MacD37, I've learned a lot from you over the years, so I hope you will take this post as it is intended.
Safe Hunting.
Clint
19 August 2004, 02:29
KurtCHot Core,
1. I would say that there are numerous designs that are capable of providing controlled feed. The goal is to never have a loose cartridge, and to never have to the bolt face able to access two rims at the same time.
2. I think that when the rim slips under the extractor depends largely on the size and shape of the cartridge. I would not try to hold a .22 Hornet and a .500 Jeffery to the same standards. I don't think it is that critical to performance, as long the above goals are met.
That being said, I put rifle designs into three categories.
1. Mannlicher-Schoenauer
2. 98 Mauser
3. Everything else