I thought I read years ago they delt better with the cold from shooting. I may be completely wrong but I kinda remember people saying the ss ones don't shrink.
I've had an original aluminium Freak kit for over 13 years. It's a kit that's been used heavily, sometimes the inserts have been in the case, sometimes chucked into the gear bag. They are all still in great condition, few slight scratches on the outside from being pulled in and out of various backs over the years but they are still perfect where it matters. Never saw the point in the SS inserts, beside bling, you'd have to try pretty damn hard to feck up the alu ones.
Real purists get custom made brass ones anyway because, well, brass!
http://www.mcarterbrown.com/forums/dealers-forum/108721-brass-freak-compatible-inserts.html
http://www.mcarterbrown.com/forums/dealers-forum/108721-brass-freak-compatible-inserts.html
The coefficient of thermal expansion for stainless steel differs depending on grade, as does that for aluminium depending on alloy, however, for comparison, most grades of stainless steel will have a higher coefficient than most aluminium alloys.
In the real world,on a cold day you'd just choose a larger insert, as the day warmed up you'd switch to a smaller one, assuming the sizing of the paint remained constant, which it wouldn't, For best practice you'd resize as ambient temperature changes.
Brass, would typically have a coefficient of thermal expansion somewhere between the two, dependant on the zinc to copper ratio of the material. The downside of brass as I see it is you'd need to keep a couple of spare fluffies and a pot of metal polish to keep them clean as brass oxidises quite quickly (Obviously stainless steel doesn't and aluminium inserts are anodised to prevent corrosion) This would, over an extended time period affect the sizing fractionally.
For the ultimate insert material use titanium, it has a lower coefficient of thermal expansion than stainless steel, naturally forms a protective oxide layer preventing further oxidisation (or can be anodised) has a better strength to weight ration and, as an added bonus, you may well get to see sparks fly from your barrel in low light conditions! However, they would be more difficult to manufacture and more expensive.
As far as weight goes, titanium inserts would come out at about half the weight of stainless steel ones, whereas aluminium inserts would come out at about half the weight of titanium.
Unless we are sizing paintballs with one of these then we need not worry too much which material our freak inserts are made of
cheers guys really appreciate the feedback, purchased the aluminium ones!
