Ok first off let me just tell you that CS:S has had hit box registry issue since it was made and in no way, shape, or form is this a fix it all. With that being said we should know a few things about CS:S and it's hit boxes. Instead of telling your right off the bat what's wrong with CS:S hit boxes I'll just post a video for you to watch and enjoy.

DoD:S lerp - YouTube

Yes, the video isn't CS:S but it runs on same engine so same rules apply. If after watching this video you find that you have that problem with hit boxes then this post is for you. If you find that you have no problem at all with hit box registry issues then you may want to ignore this post but feel free to read up on it anyways.

First lets start with some basic commands that you will be using.
-net_graph 4

First and foremost you need to have net_graph enabled to see your numbers that your are playing with. There are a few net_graphs that will show you your LERP but I personally perfer net_graph 4.

cl_updaterate and cl_cmdrate are rates at which you upload (cl_uploadrate) and download (cl_cmdrate) from the server. This is how your computer and the server communicates. This setting should be set to the rate of the server. I'm not 100% sure about this but I've heard that there no longer exists 100 tic servers, thus we're left with 66 and 33 tic servers. Either way set your rates = to tic rate. NG utilizes 66 tic servers so set them to 66.

Next are the interp commands. All these commands have to do with the way in which the server predicts movement and bullets shots. What they do is they average a bunch of frames from the server and your computer tries to guess where the enemy is at or whether or not he fired a shot at u, etc. This is what is called LERP or client-side linear interpolation. Basically the more LERP you have the smoother the graffix but the farther you are update information. This is kind of like streaming a video from your computer to a mobile device. There it may look fine if you have fast enough speeds but the video will be slower on the mobile device than from it's source. Basically, low LERP = more accurate, high LERP = more smooth graffix.

So how do we control LERP then? well if you have cl_interp_all set to 0 then LERP manipulation is simple. To set LERP set cl_interp_ratio = 1 and then your LERP will be 100*cl_interp settting. So if you have a cl_interp = 0.040 then your LERP will be 40ms. If you don't have cl_interp_all = 0, then it gets quite complicated and you have to do math. Lets not and say we did and just use the method mentioned above. Next is the cl_interp_ratio. This in simple terms is for backup packets. If you have high ping or have loss packets then setting this to 2 might benefit you since it's designed to send more packets. I set mine to 1.

Now that we know how to manipulate LERP settings what should we set it at? This is the most important question and one that I have yet to be able to give you a good answer to. I've been reading up on it and testing it over and over again and have yet to find a solution that will work all the time. This is what I know tho.

*First you want your LERP LOW! The lower the LERP the more accurate the picture your seeing is. So when you aim that Deagle to their head and pull the trigger you are indeed shooting their face and not missing them.

*Second, your LERP should not be in the red, orange, or yellow. It should be white on the net_graph 4.

*Third, you want your LERP to be close to your ping shown in your net_graph 4. Usually +10-20ms.

*Fourth, if you get a lot of choke you may want to lower your rate and if you get a little loss then up your rate. (does not apply if server has rate forced)

I've been testing this off and on for a few months now and have yet to get a really consistent reading but so far going from what I've written my registry issues have come to a bearable state. I've ran in the server and have tested cl_interp = 0 which bring you to lowest allowable LERP setting by the server. Here I notice that the hit box registry is very very accurate BUT there will be times that my shots completely disappeared. So it's a hit or miss. I feel this is because since the LERP is so low that it never registered the shot at all and not just missing the hit box. This is highly not recommended. This holds true for all the orange and yellow range LERP settings I've tested with the higher the LERP the less of the magical disappearing bullet.

By default your LERP is set to 100ms in case some of you try this and don't like it and want to go back but forgot to write it down. Default settings are: cl_interp 0.1, cl_interp_ratio 2, cl_interp_all 0.

Hopefully this little guide on LERP will help some of you with your game and maybe some of you can give some input if I've mistaken on some information somewhere. Maybe if enough people put their heads together we can find a solution to CS:S and it's hit box registry issues....probably not tho lol.