Advocate
That I have seen, the ONLY mfg that cuts a chamber for a belted mag corretly is Weatherby. I am suspect that this is due to the "octane" of the rounds they have. If they ran chambers "loosey Goosey" like everybody else, they would end up with a lot of incepiant case separations.
On a belted case, it headspaces at the front of the belt. The problem comes from there forward. If, and it is in 99.99% of the cases, the chamber in FRONT of the belt is long, then when the case is fired, the brass flows forward. One only needs to look for the shiny belt ahead of the belt on the brass. The particular 350 showed better than .090 of stretch.
If you cut one of these cases in half the long way, you will readily see what goes on. The case wall will appear uniform to an area just ahead of the belt, here it will be visualy thinner. Repeated full length resizing and fireing will agrivate this until the case comes in two! Can get quite lively, and dangerous.
For the chap who owns a rifle that the chamber is not WAY over length, and if he shoots factory stuff and does not reload, there isn't much of a problem.
If you shoot, or have shot Weatherby rifles in Wby cals you know the brass and ammo is quite expensive. Here, the reloader would like to get a fair ammount of reloads to save money by not having to buy new brass all the time. Like I said, Wby does it right. I have loaded some 300 Wby cases as many as 30 times and they still were good.
In "the other" guns, the only thing you can do is back off the sizing die so the case only stretches the one time. Kinda like fireforming a regular case.
For the record, belted cases are not the only ones to see over length chambers. I have seen 30-06 brass that showed near .200 of stretch just ahead of the web! If the back section of the case is tight (remember the cases are tapered so this can be so) the headspace will be ok and the round will not slip forward and fire. BUT, and here we go again, the case can, and WILL stretch to fill the empty chamber. It's enough to drive a serious reloader to hit the sour mash :wink:
This is one of the reasons why I just LOVE the straight wall cases. They simply don't stretch. There is no shoulder to blow forward, so case stretch is minimal. Too, straight cases are rimmed, and that's what they headspace on.
Most of the cats I know who are serious about 10 shot 1 hole groups would sooner fry in Hell as to full legth size a case. These guys neck size only, and, some even go as far as to neck turn so wall thickness is uniform and bullet pull is constant.
This is relevant to bolt guns only, as levers and autos do not have the camming power to use these accuracy Indian tricks :wink:
Once, I want to say it was .......10 or so years ago, I bought a pair of Sauers in 375 H&H. Took a couple of boxes of factory stuff and headed out to the range. On the 1st shot with the 1st rifle I thought the recoil was queersome. When I lifted the bolt it felt WAY to easy. That was on account of only the belted piece of the case came out! The second rifle, ditto. Made record time in bring BOTH rifles back where I bought them and got my money back. These were both new guns?
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Been saying for a while now, quality has become a non entity :?
Coug