Odd Lengthening of case ?

[Rumble]

OK-- I have an odd one. I am reloading 280 Remington. The rifle is a stock Remington 700 Mountain rifle with stainless action and barrel. I am using new and once fired Remington brass. The load consists of 140 gr. AccuBond pushed by 56 grains of RL19. My problem is the case measure SHORTER after being fired---2.531 unfired and 2.528 once fired. No signs of pressure, and bolt functions easily both closing and opening.

Any thoughts as to what is happening?

 

[Guest]

I'm going to bet if you measured the diameter of the case at the shoulder/case wall joint, and at the neck, it's a noticeable jump from the loaded round. That can cause shortening, as can tight chambers, but you should feel that when you close the bolt. I'm going to stick with the idea that your chamber is close to the max spec for the 280Rem in terms of diameter, and if you compare cases, I bet the fired stuff is not nearly as tapered and is larger in the shoulder and neck diameters.

 

[Rumble]

That does sound reasonable. My next problem that occurs as a direct result of the "shortening" is now the cases are too short and the neck isn't being properly resized. I am using a Lee neck sizing die and the case isn't extending up into the die far enough to fully engage the collet. This appears to be caused by the decapping pin bottoming. I can remove the decapping pin/rod and visualize the case then being worked. Does anyone know a sizing die that can be adjusted in such a way to keep the decapping rod/anvil in place but still adjust for shorter cases? I can work this process with Lee die, but it adds very time consuming steps of resizing three times; once to decap, once to neck size down, and then again with the decapping pin reinstalled to expand the neck to correct size.

 

[RiverRider]

I can't tell you anything about the die and how to adjust it, but a .280 case that is 2.528" in length should be no problem at all. Suggested trim-to lengths are just that---suggestions. A couple of thousandths of an inch either way doesn't make any difference at all. You should be able to trim to 2.520" or even less and experience no difficulties.

 

[Rumble]

I agree with the trim to length being a guideline only. I think the true issue is with the basic design of the Lee sizing die. The decapping rod is a fixed length; shaped much like a nail. It has no length adjustment and is simply held in place by a screw on cap assembly. I believe some of the other manufactures offer dies where the decapping pin can be screwed in or out indepentant of the die body to adjust for length. Thank you to all who helped with this problem.

 

[Ol` Joe]

All brass normally shows shortening after fireing that is due to the case expanding out to the chamber walls. The When you resize the case it will "grow" from the diameter being reduced and usually end up longer then before you fired it. Think of it as a piece of putty you have in your hand. You squeeze it and you reduce it in one direction but make it grow in the other. This is all normal and common. This also is the reason you should measure and trim brass AFTER resizeing, not before. You don`t know how much "growth" will occure from the sizeing operation.

Edited to add;
The neck sizeing operation won`t move enough brass to make the OAL growth show or very little if it does. This is the reason for the added case life you hear of when useing these dies. You die will still resize from the shoulder forward, the same as if you used a FL die. You`re fine, don`t sweat it.

 

[Guest]

I've had generally good results from the Lee Collet dies, but I've also used Hornady neck dies (which are caliber and length specific, rather than cartridge specific, so get the 'long' or 'short' version as you need. They have an adjustable decapping stem and it's easy to deal with. They're also pretty reasonable cost-wise.

 

[Rumble]

I generally have good luck with Lee dies as well. I have several sets in different calibers and have had no problems. That is partly why this particular problem is so puzzling. Thanks for the info, I had been looking at a Redding die on MidwayUSA. Anyone know if this decapping pin is adjustable on that particular brand?

 

[BK]

Yes, it is. Redding also offers a tapered and a carbide sizing button that replaces the standard steel button.

 

[Ol` Joe]

If your neck sizer is a Lee collet type they stop sizeing ~0.10" from the should of the case by design. The collet does know what the neck lenght will be so it sizes a tad high to prevent it from bottoming out on the shoulder.
Some don`t like this, but I tend to think it offers a neck diameter "ring" that helps center the cartridge in the chamber. Then again I`ve been wrong about this thinking thing before........

 

[Guest]

I've recently used Redding dies for the first time. I don't care for them. They are sloppily made and the ammo they make isn't great, either. I noticed a while back that the lock rings are drilled waaaay off center. Makes me wonder about the dies being reamed off center, too. I trust my Hornady dies much more. For about $20, you can get a Hornady neck die, and it has a tapered (elliptical) expander ball. They're terrific dies. I think their seating die is also great.

 

[tjRoberts]

old joe has your answer,
When you fire your rifle the brass expands to tighly fit the chamber.
If you full length size your brass it will get longer.
...tj3006