Need help identify a bag of bullets

[Dylan Defense]

I am new to reloading. I need help identify a bag of bullets I got from a fellow Calgunner. I was told that they are Hornady's 55 gr but I have no way of verifying that. The bag was sealed and had no label affixed to it. The bullet weighs exactly as a Hornady .224 55 gr FMJ-BT with cannelure but measures longer as you can see from the photo.

I would greatly appreciate your help ID'ng this or for advise on how I can safely reload these using once fired brass, CCI $400 primers and either an IMR 3031 or IMR 4198 powder. THANK YOU!

[ar15barrels]

Start with 55gr starting loads and see how they behave on the chronograph.
If the velocities run higher than the book from the same barrel length, you will have to reduce your loads from the book.
If velocities run lower than the book from the same barrel length as the book, you are often ok to exceed the book.

[MongooseV8]

They look like Nosler Custom Comps to me. How did you verfiy they are 55 grain?

I have weighed like 30 bullets at once then divided to get a more accurate reading.