Went through my regular brass prep to load up and try out some 140 eld m in my 6.5 creedmoor.

Got to the loading part and the bullet felt really loose seating. I went to measure the ogive OAL and the bullet slid into the case.

I have been using 142 SMK with no issues with neck tension

Brass is lapua with 2 or 3 firings

Die is a TYPE S Bushing die. The bushing size I have used the whole time is .090.

I swapped to a .089 and had no further issues.

I measured some bullets both the 140 hornady and the 142 smk and they were both .264 or .263.5

Is it an annealing or lack of issue?

Necks are hard, need to anneal or replace.

Hard already?

Max of three firings no where near a max load either

1) Is the rifle a bolt action or semi-auto?  For a bolt application, you will want a neck tension around 0.002 ± 0.0005.  For semi-auto, about 0.001 more.  Measure a loaded round neck OD in the brass in question (different brass manufacturers have different neck thicknesses).  This is your reference point.  Then shoot for a sized neck OD 0.002" less to achieve a neck tension of 0.002".  Adjust your neck bushing according to get the desired end result.  Be sure to adequately lube your cases/necks when sizing.  And if you plan to anneal, anneal EVERY loading cycle (at least once) for consistency (I anneal before sizing).  Some folks (AKSR) anneal 2x per loading cycle!!!  If you are using neck sizing bushings to adjust your neck tension, you don't need an expander so you should remove it from your sizing die.

2) I don't understand a 0.090 bushing.  My bushings for my neck sizing dies are the size of the OD of the case neck.

For my 6.5cm lapua brass, I have found .288 bushing followed by a .262 mandrel give me around .002 neck tension.
.289 bushing was not providing proper tension.
Using short action customs bushings.
Your mileage may vary depending on bushing brand.
I anneal every firing too.

My mistake i was using .290 bushing. Fired out of a Bergara bolt.

I switched to a .289 bushing and the neck tension is much better.

Looks like I’ll be looking into buying an annealer

Did you remove the expander ball and replace it with the decapping pin retainer?  Letting the bushing control the neck tension?

Get a smaller bushing.

I prefer using more neck tension as opposed to crimping. I want a minimum of .002" for a bolt action, .003" minimum to .004" for a semi-auto.

I recycle brass after the fifth firing because I don't want to anneal, and I feel I already got my money's worth out of it.