260 Remington Starline brass issues

Houser in NC

New member
I’ve been a reloader for over 40 years. I have never run into this before and have reloaded thousands of rifle cases over the years. Maybe some can tell me if this is normal.

My rifle is a stock Savage Model 11.

The new 260 Remington Starline brass length was correct straight out of the box and the first loads fired were mild. After firing, I set my sizer die to bump the shoulder back .002”-.003” so it would chamber easily. After sizing, I checked the case length and it had got .003- .004” longer. ( I know cases will get longer over time and need trimming. )

After each firing and sizing, the cases continue to get .003-.004” longer and I have to trim after only 2-3 firings. All loads are well below max according to all the manuals I have read and no signs of high pressure. Load is, 123 gr Scenar, 43.1 grs H4350, CCI 200, 2.280” OAL, 2890 fps avg.

I tried bumping the shoulder only .001” and neck size only but the cases still get longer. Trimming after only 2-3 firings on a case seems odd. Is this normal with the 260, or is it just with Starline brass?
 
My personal belief is that sizing w/ a regular sizing die and neck expander button stretches the necks more than, or as much as, the firing itself. If you're using regular dies, you could try a neck die with no expander and a body die, or polish the existing neck button and try it. Lubing the inside of the neck w dry lube like mica or graphite may help too. Ive never tried the rcbs x dies, but they are said to help also.
 
Thanks for the reply Mike.

I’m going to try a collet neck size die and body die and see if the issue goes away. Hopefully that will fix everything. I ordered both dies today.
 
So after firing once the brass(before sizing) chambered with too much bolt effort? Was the firing pin/spring out of the bolt? It would be unusual for brass to be fully formed in one firing. I use a universal decapping die so my sizing die is "stripped" I then use a mandrel to set the I.D. for neck tension. This will reduce case length growth. The other reason is a slightly larger internal diameter difference between the chamber and the sizing die. Rifle chamber "fat" die "skinny" so the body is being moved more than your other rifles, moving the body always increases the brass length more.
 
I've loaded several hundred pieces of Starline brass for my 6.5 Creedmoor. I've loaded them several times, all without any problems. Sounds more like the expander button may be at fault. I'm using standard Redding dies.
 

I’m going to try a collet neck size die and body die and see if the issue goes away. Hopefully that will fix everything. I ordered both dies today.

I use Collette die and body die on several calibers.
Lee used to make mandrel of different diameters for a fee. As a custom order at one time. I got 2 or 3 different mandrel for a 204 Collett die one time
 
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