This one kind of hard to get in most of the maps as dying just once will invalidate all your progress, I got it at baggage after quite A LOT of tries, I wish I'd seen this sooner though... I was playing an offline match trying to get other achievement when I realized a more effective way to get it.

Let's start by reading the achievemet's description and understanding what we need to do:



Ok, so: "Win an Arms Race match without reloading any of your weapons"

What does that imply?

• No manual reloading (not pressing the R button at all
  
• Not dying (not completely sure about this, when I died doing this I didn't get the achievement but people tell me you can in fact die, but if you don't die while following this guide you can get the Rampage achievement as well, so that's a bonus and it's really not that hard)

So the thing you're trying to do here is to have at least one bullet left in your weapon before it automatically upgrades to next one (if you find yourself with just one bullet left you can try your luck with the knife)

In the CS:GO lobby, you are going to go to PLAY and select OFFLINE WITH BOTS, then in Common > Arms Race you are going to choose the map "Safehouse".



The minimum difficulty required in order to be eligible to get achievements when playing with bots is easy, so go ahead and select that (I've actually tested it with this difficulty and completed it without problems).

When you're prompted to choose a team go for the Counter-Terrorists.

Now that the match has started, get your knife out and head to the following location:



If you spawn to the right of the house just head straight until you pass all the columns and turn right, if you spawned in front of it even better, just head straight and then open the door.



Once the door is open you'll see the stairs to the upper level, follow the stairs and once you're up you'll see another door at the end of the corridor, right in front of you, open in and you'll see this:



If you were fast enought nobody will be there just yet, enter the closet on your left and position yourself aiming at the window like this:

These are the easiest of the bunch, just keep aiming at the window and when a bot of the T side shows up spray him,



The same applies for the sniper rifles, you just have to use the zoom for these (obviously)

For the shotguns you're gonna have to move from your camping spot as it would be significantly harder to kill the terrorists from that spot with the short-range shotguns.

Just get out of the closet and head to the window, set up your aim like this:



Now just wait for a bot to come through and shoot it, aiming high helps in this part, but they'll usually die in the first shot from that distance.

Once you're done with the shotguns, head back to the closet.

Same principle as before, just try to get those headshots and fire your guns in quick bursts to take the enemies down asap.

Hopefully, the room will be clear once you get the golden knife, if that's the case just head back to the window, and take the same spot as before (in the shotguns part), wait for someone to get in and get him, I believe using right click is more effective, also you get the chance to get a one kill with the knife while using the right click if you attack directly from behind, otherwise it usually takes two hits.

If you correctly followed the steps in these guide and had a bit of luck not getting shot from other places you should now be proudly displaying the Conservationist achievement on your profile, congrats!

I got this while playing the match I got the screenshot from, so it shouldn't be very difficult to do.

• Don't get impatient and go out to get shot at, having most of your life is very important for when you get the golden knife.
  
• Try not to waste bullets, using about half the clip for each kill should be okay though, as you are automatically given the next weapon with every second kill you get.
  
• Usually the bots will come through the window one by one, sometimes in pairs, or even more at times (not very often)... so be prepared to shoot at several targets very quickly in case you have to.

Please rate this guide if you found it useful, any kind of feedback is welcome (please don't comment things unrelated to the guide)

Have a nice day!