Aha! So I’ll blame it on that Pratten guy. 
Incidentally, I’ve noticed that if I aim my airstream down too much on such a shallow chimney I can actually produce a sort of Doppler effect. Weird. Very, very weird.
Thanks, Gordon! And good point on the Blowhole Variations, as well.
Hmm…Anyone out there got a Pratten and a set of Calipers? I’ve got an R&R around (and too many calipers to keep track of!) and would be interested in putting this to the test with numbers…
Loren
normally a Pratten model will have a shallower chimney and larger embouchure.
You can visually see that the heads are a bit thicker on the R&R, and the bore might be a bit smaller.
Eilam et al.,
If what you say is correct that a (Hammy) Pratten has a shallower chimney
and a wider embouchure hole than R&R’s, what are your suggestions about how to approch playing a (Hammy) Pratten? I find my Hammy is a more demanding flute to play than my other flutes.
Paul
Oh, well I corroborated the shallow chimney of the Hamilton (very similar to Dave Migoya’s authentic Hudson Pratten), but I feel that Hamiltons are not demanding at all to play. It plays very easily, I think, and can be pushed further than most flutes I’ve played as well.
I also disagree about the wider embouchure – it’s not wide, at least not as wide as, say, a modern silver flute, or the German flutes, or some of the more modern “Pratten-ish” flutes floating around.
But Eilam’s right that it does have a slightly wider embouchure than most Rudalls. I think the reason some find it more demanding than other modern “Prattens” is that the Hammy embouchure is a bit smaller and rounder, in fact.
Tips for playing it better would be just focusing more, and nailing it. Takes some time, but it’s worth it.
Gordon
Hi Paul.
I think that the Hammy has an ovalish embouchure, and that where some have problems, because if you don’t have a very focused embouchure there will be a hiss, or if you don’t place the flute exactly at the right spot, that’s why some makes prefer squarish embouchure (bigger initial success rate) there more forgiving, and that’s also the reason why so many player say that playing the Hammy improves there play on other flutes, forces you to develop a good embouchure.
I feel that the approach to playing a Pratten type flute, is to make sure you fill it up, like a race horse that excels when pushed to go fast, you would not choose a fire Hydrate to water a Bonsai tree, Prattens are meant to spray buildings!
Any way, I had some wine, I hope it makes sense, if not, forgive me, I hardly ever know what I’m talking about anyway 
I think that’s exactly right, eilam. Hamilton, like Wilkes and a few others, kept his embouchure cut much more akin to the 19th c. counterparts, whereas many other makers, while copying the large hole and bore of a Pratten, gave their flutes a more forgiving, wider, and sometimes semi-rectangular embouchure. This, I think, takes some of the ultimate tone away from the flute, and encourages a weaker embouchure, so some find flutes like Hamiltons’ somewhat harder to control.
Once controlled, though, I don’t think any of these flutes are particularly hard to play, and the control will allow other flutes to seem that much sharper. As you say, they can be blasted, but can also be played delicately, although no Pratten style, due to the bore and hole size, is a flute to relax with.
Watering a bonsai with a fire hose? Save a drink for me, will ya? 
Gordon