Not getting Tax credit for traditional IRA amount

Why I am not getting full tax credit the money that I deposit to my traditional IRA account? I can deduct only $300  of the contribution. I don't have a retirement plan with my company I do have 401K option. Also I am within my gross income range $109K to $129K  not over $129K bit less than the max range. Any idea why I am just getting tax credit for $300 not for $7K? Do I need to go for Roth IRA?