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The kind of loading data you want is sort of complicated.  SS109s are longer than standard 62gr bullets, and bearing surface length is important.  There are 65 and 69gr bullets out there with similar bearing lengths; start your load development with that data and work up.  You will find plenty of "recipes to duplicate M855" on the Internet...consider them data points, not authoritative.  Actual M855 is made with non-canister grade powders whose loads are tweaked regularly through extensive testing - testing you and I can't do because we don't have the kinds of labs Lake City does.  If you want M855 performance, work up a load with similar velocities AND consistent accuracy, and remember that an extra 100 fps may look good, but it could ruin your accuracy; if you get similar velocities to M855 with consistent accuracy, lock in your load and don't try to get that extra 50 or 100 fps to "match" the stated M855 spec.

It's also kind of important to NOT call SS109 bullets "steel core" because they aren't.  They have a LEAD core and a steel "insert" or "penetrator" inside the jacket tip.  This moves the center of mass back and allows the bullet to retain rotational stability for longer flights.  SS109 bullets are, as a component of M855 ammo, specifically NOT considered armor piercing under law, but actual steel core bullets ARE.  Let's not get a bunch of uninformed people into an uproar thinking we're loading armor piercing ammo when we aren't.

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I am loading 62gr ss109's at 25 grains of Varget and am having good luck with them,  my buddy runs 27gr of Varget with the same bullets but that seems excessive since I am getting great groups shooting mine out of a 16" 1/9 twist ar barrel and a 11.5" 1/7 twist ar barrel.

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SS-109 loads,
I used the start loads for the Speer 62 gr FMJBT (lead core), and worked up.
In my rifle these loads are safe, and are 1/2 gr below the first signs of pressure.
All these loads use LC brass trimmed to 1.750, neck deburred inside and out.
Primer pocket swaged, Win SR, pulled SS-109 62 gr FMJBT seated to mid cannelure.
Crimped with a Lee FCD (factory crimp die).
My rifle has a 1 in 9 twist, 16 ", 5.56 chamber.
AA-2230, 24.5 grs. Shoots great.
H-335, 25.0 grs. OK load, just that other powders are more accurate. ( In my rifle)
BLC2, 26.0 grs. My favorite SS-109 load.
Varget, 26.5 grs. Most accurate SS-109 load in my rifle. Just a hassle to load.
Tac, 26.0 grs. Another good load.
W-748 25.5 grs. Not accurate in my rifle, your rifle might like.
Remember to work your loads up, your rifle may be different from mine. YMMV.

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What kind of velocity are you getting with them? Out of the 16" barrel.  I live in the land of no NFA, so the 11.5 inch barrel would not apply for me.

ETA: what primers are you using?