Although some recommend it, I have never found neck sizing with a FLRS die satisfactory. The FLRS die resizes the body to some extent, and in my rifles it is enough to make the rounds too difficult to chamber. If it works for you then go for it, and it will save some money. I buy Neck Sizers for all my rifles.
Ecclesiastes 12:13 *¶Let us hear the conclusion of the whole matter: Fear God, and keep his commandments: for this is the whole duty of man.
14 *For God shall bring every work into judgment, with every secret thing, whether it be good, or whether it be evil.