Large O Ring Replacement Sizing. 40mm Moscarts)

[Asomodai]

Hey guys. 

Tested my 40mm shells for the first time (Firing empty). Unfortunately 1 of the 4 keeps blowing the large O ring off when fired. 

I have measured the O ring at being 30mm inner diameter with a 1.7mm cross section thickness. I can't quite find that sort of size thickness. Only 1.5 or 2mm. Is there a problem with using slightly thicker or thinner o rings?

Also shall I go for a slightly tighter fitting inner diameter O ring considering this one ejects itself when used? Maybe a mm or 2 smaller?

Cheers!

View attachment 56157

 

[Adolf Hamster]

if it's the one at the top for holding the bb's in then the thickness shouldn't matter.

the only issue with a tighter one is that it acts kind of like a radial hop unit (gives spread) so maybe might send a few more bb's out rather than forward, but apart from that can't see an issue.

i did something similar with a madbull shell of mine and not noticed any performance change (ie it's still underwhelming)

 

[Asomodai]

if it's the one at the top for holding the bb's in then the thickness shouldn't matter.

the only issue with a tighter one is that it acts kind of like a radial hop unit (gives spread) so maybe might send a few more bb's out rather than forward, but apart from that can't see an issue.

i did something similar with a madbull shell of mine and not noticed any performance change (ie it's still underwhelming)

Spread might not be a bad thing. For now I have order 25 Nitrile O-Rings in the closest size which I believe is imperial. 29.8mm ID with 1.78mm Cross section thickness. Considering how much O-Rings stretch maybe going slightly tighter in ID might be the better option. We'll see how these fair when they come through. 

Cheers!

 

[Asomodai]

if it's the one at the top for holding the bb's in then the thickness shouldn't matter.

the only issue with a tighter one is that it acts kind of like a radial hop unit (gives spread) so maybe might send a few more bb's out rather than forward, but apart from that can't see an issue.

i did something similar with a madbull shell of mine and not noticed any performance change (ie it's still underwhelming)

Just got them in. Perfect sizing! Slightly less ID then the original, (But original is stretched so probably what it was supposed to be like from factory). Cross Section width is fine too. 

Happy days. £2.50 fix for 25. 

 

[Adolf Hamster]

Just got them in. Perfect sizing! Slightly less ID then the original, (But original is stretched so probably what it was supposed to be like from factory). Cross Section width is fine too. 

Happy days. £2.50 fix for 25. 

happy days

if only the sealing o rings were as easy to get right.....