Does anyone know how Mountain Hardwear rate their sleeping bags ? They seem to put one temp rating on each bag but don't attempt to say whether it's a comfort rating, minimum comfort rating or the extreme rating. Their website really doesn't help either :(

Mines got three different ratings but dont really make much sense.
iirc it's a -12 bag and I was sweating on last years winter bivi.

This thing here says 32 degrees (so 0 degrees celsius) ... 500g of 800 fill power down, so feels quite snuggly (special technical term).

EDIT: I've just seen that 0 is minimum comfort, shame I was hoping that would be the 'normal' comfort rating.

Tbh 500g of 800 fill (assuming US) should be ok lower than zero. What is the overall weight out of interest?

Ignore Mr Fish, he's got a Mountain Equipment bag ( I think ) which have the standard 3 zone rating

I think you might be right Matt :?

What is the overall weight out of interest?

1.2kg for the bag but it does have a waterproof / breathable outer and waterproof zip so slightly heavier than you might expect.

I was hoping it'd go below 0, I've another bag here that weighs 980g and has 550 fill power and that has a comfort of 0 and a bottom comfort of -4. I'm not sure of the fill weight but I'd guess at around 500g.

That weight seems respectable for it's fill weight and features. As reference my PHD Minim 600 (600g EU 800fill) weighs 1063g, with no zip and is rated at -16C, which I suspect is equivalent to a lower comfort rating. My experience of PHD bags is that their ratings are quite conservative.

The PD400 has 400g of 750+ EU and is rated to -3'C

Anthony, your PD400 is similar to my Rab Alpine 300, which contains 300g of down (don't know fill weight) and is rated to -2 degrees. Whole thing weighs about 600g (no zip).

I've not got one Ian, just using it as an example for Stuart's bag temperature being conservative. I do have a PD800 and have to say the quality is absolutely brilliant, regardless of the price, I see why they sell out so quickly!

Ive often contemplated the PHD Minim 300 as a useful bag to fill the gap from Minim Ultra to Minim 600 or PD800. It sounds similar to your Rab.