I have a 7mmRemMag that I am neck sizing cases for. Somehow, after firing or after neck sizing, the base of the case will no longer fit into the chamber. I have tried full length sizing, and it has not solved the problem. What is causing the cases to swell at the base to the point they will no longer fit into the chamber. I always thought that neck sizing would allow the case to remain the exact same size as the internal dimensions of the rifle which would llow the case to always fit just right. ??
How are you certain it is the base that is causing the problem? If it truly is the bases, the only answers are, something in the chamber obstructing, or your loads are way hot and causing excessive expansion of the bases. That latter you would know with difficult extraction on firing.
The most likely problem is that in neck sizing you may be using an FL die which is expanding the shoulder without sizing the body at the shoulder, or your cases may need trimming.
Posts: 1261 | Location: Placerville, CA, US of A | Registered: 07 January 2001
I am certain it is the base of the case, because the cases are nickel plated, and the nickel is rubbed off around the base just above the case belt. I am using a fairly hot load, but how could the base swell past the internal dimensions of the chamber? In fact, I just rechecked everything, and the cases that have just been fired will not go back into the chamber. Having discovered that, how could the base swell past the internal dimensions of the chamber?
quote:Originally posted by 38Special: I am certain it is the base of the case, because the cases are nickel plated, and the nickel is rubbed off around the base just above the case belt. I am using a fairly hot load, but how could the base swell past the internal dimensions of the chamber? In fact, I just rechecked everything, and the cases that have just been fired will not go back into the chamber. Having discovered that, how could the base swell past the internal dimensions of the chamber?
This is a difficult one...try to shoot a round and take a marker and mark the case base at 12 0'clock and then remove it and then with the mark at 12 oclock see if the case will return to the chamber...the chamber may have expanded in a "egg" oval shape thus keeping a non-indexed case from reentering the chamber.....this is the only thing that I can think of on a non-resized case!!!if it was on the resized cases then I might consider the die as being mismachined on internal specs.....let us know what you find....we are all still learning...if we are lucky ..good luck and good shooting..with proper fitting cases...
Posts: 687 | Location: Jackson/Tenn/Madison | Registered: 07 March 2001
It's hot loads then. What is happening is that the slight irregularities of the brass and chamber aren't conforming when they go back in a different orientation. That would be more likely with nickel plated brass which has less springback than unplated brass. Much the same thing happens at the shoulder in normal loads. That is why you have to resize after about 4 or 5 loads. The brass quits springing back and the only way to get it to "fit" is in a sizing die. You'll have to full size your cases to get them to fit easily in the chamber. Jusst one of the problems of nickel plated brass.
Posts: 1261 | Location: Placerville, CA, US of A | Registered: 07 January 2001
If you are experiencing the problem of swelled bases after only one or two reloadings, then your problem is definately related to excessive pressure. The nickel flaking is another strong indicator of a pressure problem.
Even with normal pressure loads, some brass must be full-length sized after several firings in order to bring the bases back within tolerance.
Posts: 13286 | Location: Henly, TX, USA | Registered: 04 April 2001
I'd back off a couple of grains of powder and see if you still have the problem.I think your way to HOT. Are you having a hard time lifting the bolt handle ?
Posts: 1111 | Location: Edmond,OK | Registered: 14 March 2001
How many times have these cases been reloaded? Have you measured the cases for proper length? You must keep your cases trimmed to the proper length. I have never been a fan of reloading nickel plated brass. I would throw those cases in the trash and replace them with some reliable quality unprimed brass. Are you using a full length die to neck size your cases? Are you shooting max loads on a regular basis?
I am looking at a Product Review on p.18 of the Feb 2002 American Rifleman for a Resizing Die for Belted Magnum Cases that is claimed to resize bulges ahead of the belt in belted cases.
I am looking at a Product Review on p.18 of the Feb 2002 American Rifleman for a Resizing Die for Belted Magnum Cases that is claimed to resize bulges ahead of the belt in belted cases.
I would be certain my cases were trimmed to the proper length. Be safe and avoid hot loads, they will do you or your rifle no good. Since your shooting a belted magnum round and you neck size only, that should put the head space on the shoulder and not the belt and that is fine. I have never been a fan of reloading nickle plated brass. I would throw those things in the trash and get good quality unprimed brass to load. I believe your cases have grown to long and will not chamber for that reason.
What brand of rifle do you shoot? My cousin has a Browning A-Bolt, and he can only shoot new brass or once fired. He has the same problem that you are having. His does it with regular brass also.
