75g ELDM seating depth?

[kyotekiller25]

Got the powder charge nailed down for the 223/75g ELDM/N540 at 24.7 for 2960fps. ES of 6 from a small 3 shot sample. Roughly .75" at 200 yards. I notice most if not all loads have 2 close and 1 out of the group. I started .010" off the lands so I guess I'll start seating them a bit deeper to see if things will tighten up a little.

Do you recommend doing seating depth testing at 100 yards, or would it be more beneficial to do at 2-300 yards?

Also, would you go .003" or .005" increments for seating depth testing? Do the 75s prefer any length of jump typically?

Thanks

 

[MarshallDodge]

I usually start the 75 ELD with a .020 jump.

 

[BuildingConceptsllc]

I usually start the 75 ELD with a .020 jump.

Me too.

 

[kyotekiller25]

Thanks guys. I'll probably just do a few sets 5 thousandths shorter increments then. 1.930" to the ogive should put me around .020" off.

I think I might also do 100 yards this time around for seating depth testing. Been doing 200 and 300 yard powder charge testing, but the mirage has especially been kicking my ass, along with a slight 3-5 breeze.

 

[4O6shootist]

I've found the eldm like to be 10k off, 50k off and then again back in the 70-100k off. This is with 75s 80s, 109s and 140s. Haven't tried larger diameter eldms to confirm, but data has been consist testing the smaller weights. My jump baseline is finding lands on a new barrel in a vice where I can pull the loaded round out with no resistance using my pinky nail. If finding lands with a Hornady too, that will likely add 5k or so to the dimensions as it will be slightly jammed using that method.

 

[secondofangle2]

Go 0.50 and never look back