.300 mag case life with only neck sizing

[sam700]

I'm going on my 5th firing on my Remington .300 mag brass. I've only neck sized with a Lee Collet neck sizer die. The casings have never been trimmed, and for the most part have only grown 1 or 2 1000ths after 4 firings.

The question is does the lack of need for trimming indicate that I will get a much greater life out of this brass than I might otherwise get?

How much life do you guys get when only neck sizing and using a collet die?

How bout a .308. I have some .308 brass going on 6 firings and only needing a trim after the first firing.

 

[Shoney]

There are so many variables that it is hard to give exact numbers. Anywhere form 3 to7 is not unreasonable, and with moderate loads, maybe as high as 10-12. Several factors will determine life.

How hot will the loads be?
What shape is your chamber in?

At a minimum, you should be checking the cases for head searation after each firing. You may wish to anneal the cases every 3 firings to lessen the chance of splitting.

 

[Vern Humphrey]

That's pretty much common. Brass "grows" because it stretched from just forward of the web (the thick base) when fired. When you bump the shoulder back, you are simply making the neck longer -- and ultimately you have to trim.

When you use a collet die, the shoulder is not affected, so the case expansion and stretching on the first firing is all the stretching you're going to get.

 

[moooose102]

i "dunno". for many of my shells 3 loadings is all i get before my case neck splits. i just ordered new brass (again) and i am going to try annealing them after every firing along with neck sizing only. most of the time, i shoot full strength loads, so i know that does not help brass life. i am going to try taking extreem care of this brass, to see if i can extend its life. i am going to mic the cases between loadings, i want to see if maybe i have an oversized neck in my guns chamber.

 

[Afy]

The bulk of y .300 WM brass is Federal from Factory Loads.
Am on my third load (including factory). Trimmed after first to 2.610 or there abouts.

Havent had to trim for the third cycle. Brass shows no sign of wear and tear.

Will probably anneal after foruth load if I can find the equipment.

Havent been shooting the .300 as much as I would like to...

 

[454PB]

In my 300 WM and .338 WM, I've had some lots of brass last 15 loadings, but the norm is 10. I do "partial full length sizing", rather than neck sizing. Since I started doing this, neck splits are what finally kill the brass, I've never had another head separation.