O ring help Needed

[bubblerboy64]

I'm trying to sort out O rings for my impact. I'm on the Oringsandmore web page and have some questions.

1) I am assuming that Buna 70 and 90 are the o rings required for most of the sizes needed Buna appears to be the material used in construction

2) there are a couple o rings required which are listed a PUR 90 on the parts list. What does PUR mean and I can't seem to find the exact size which are 2,84x1,78 and 2,9x1,78. close but not exact.

Looking at this stuff there are three criteria the material which is BUNA (I'm assuming) the the hardness which is 70 or 90 and then the dimensions which is thickness (last number on the parts list) and diameter which is first.

I searched the oringsandmore page for PUR and found nothing. HELP again. Thanks in advance. This stuff is simple once you have some understanding but when you know nothing it's a challenge. If I have this figured I want BUNA not silicone or nitrial John Heckman

 

[jarmstrong]

Buna,or Buna N, is Nitrile 

PUR is Polyurethane O-Rings

 

[marflow]

https://www.theoringstore.com/store/index.php?main_page=product_info&cPath=367_459_458&products_id=16197

https://www.theoringstore.com/store/index.php?main_page=product_info&cPath=367_1322_1327&products_id=27547

those o-ring are close enough in size to try the larger one, these will be very hard O-rings and I guess they're in high wear area the difference in these 2 rings besides price is, hell I don't know

even though the O-rings are post as metric they are inch sizes and the O-ring store might have a better selection

 

[heavy-impact]

Don't worry about the odd ones that never fail. The main ones are breach/barrel, valve rod, regulator and rear block. Don't buy the C3 bumper o-ring. Replace it with a delrin washer.

 

[bubblerboy64]

I think I've got what I need. Thanks all.