Customer Maintenance Friendly Gun Manufacturers

I’ve run across some frustration with the lack of information some manufacturers provide with their guns. It seems to me that a company would want to be as customer friendly as possible and make it easy for owner of the new gun to do routine maintenance. At a minimum they should provide a take down diagram. A customer friendly company would also include part descriptions and above all else o-ring sizes. O-rings don’t last forever and are easy to replace if the right information is provided. It irks me when this information is hidden like it is classified as top-secret. 

Frankly, the availability (or not) of this information now plays a large role in which manufacturer I will buy new guns from in the future. I’ve recently purchased my first Air Arms and have found they do a great job. They have a labeled takedown diagram available for the rifle, along with part descriptions, part numbers and o-ring sizes! 

On the other hand, my Brocock has virtually no information available. I love the little rifle, but am much less likely to purchase another Brocock because I get the feeling they want me to spend $50+ dollars just to ship the rifle to a repair shop and have them replace the o-rings for me. 

How are other manufacturers in regards to being customer maintenance friendly? 
 
So far with my limited PCP experience I love how FX have the diagram and every part and part number on their site. Albeit it takes a while for them to pop up there, nothing is perfect. With my Royale I don't forsee anything that I would need to send it off for. The only area I haven't taken apart and put back together is the valve assembly, I love seeing how things work and seeing how it works and put together only makes me love my rifle even more. Swedish precision.