How much does postage from the US cost?

I'm looking at doing an order through Brownells but can't get any indication of approximate postage from them unless i actually buy the stuff.

The order should be around 3kg and not very large. Checkout price $285USD which equates to around $345NZD. I've got a couple of extra items i could get rid of if i knew i'd be cutting it close.

Someone said Brownells/Sinclair default to really expensive shipping unless you tell them not to specifically. I can't remember the details but would like to know which option is best.

I'd also like to see some figures from peoples actual completed orders if possible.

USPS Priority Mail is the best. Don't click on "first class shipping" or it will go on a boat. Brownells don't charge a lot for priority mail, a lot cheaper than some other places

freight has been from 30-70 for a box not much bigger than 1 doz cans... Add that to your current order and you are in GSt teratory + if you ghet picked up the extra $40 of fees on top of the GST

$46.40 uS for 3 x Stripped AR15 lowers, Shipped friday and currently sitting in customs. 5 LPK kits cost me 11.90 in freight from Brownells using Parcel Priority Express Mail

have a look at prezoom a nz owned freight forwarding company that charges nz $20 for the first 500g and $4.50 for each 500g after that.
Bloody good if you get free freight with in the states.
also based in delaware so no extra taxes apply

I wouldn't touch any of those freight forwarders with a barge pole.
They decide what they will ship and how much it costs. The xx per 500gm is bullshit as 500gm is about the size of a beer can, and bigger and you pay through the teeth.
If they decide not to ship, then you're stuck with your shit in the US
Customer service is done out of Singapore and is a joke.
Hop Shop Go was the big one, owned by PayPal. Very anti gun/ hunting etc
Nz posts one is though the same gateway company in Portland Oregon.

Ask me how I know all this... LOL
I eventually got my stuff, 1/2 of it missing and a huge freight bill.
Imagine trying to tell someone who's English is crap and has no idea that a OAL gauge is NOT loaded ammunition...

I've not got stuff from Sinclair's (now owned by Brownell's) for a while but when I did the freight was pretty pricey and they would not use cheaper options, even sending the stuff in relatively large boxes with lots of packing (so I was paying for unused volume). It put me off a bit but then it's not Sinclairs anymore but a different branch of Brownells.

Opticzone, Boyd's stocks and The Rifle Scope store charged me $40-$42 for a bigger padded rangefinder sized box and even bigger spotting scope box with tripod etc and obviously stock sized box from Boyds.
All used USPS Priority International with good tracking updates, sign for delivery etc, Takes about 7 days all up usually with 2 spent in customs and then always delivered next day after that cause I'm in Auckland, same as the mail centre.