Knitting needles - made in the USA ?

I have been wanting to make this red coat for a while.  I finally got round to order the yarns and pattern and am ready now to make a start.

I normally don't have much problem with getting the right tension/gauge but this one throws me off totally.  This knitting pattern is from the US and asks for size 6mm knitting needles and chunky weight yarn.  

I knitted a swatch and it was way off.  I knitted a second swatch and it was much better.

The difference?

The first swatch on the left used 6mm knitting needles made in the UK.  The second swatch on the right used size 10 (6mm) knitting needles made in Montana USA.  

I guess where your knitting needles are made are important.