Tungsten is not inexpensive any way you go about it. I added 1.2 pound tungsten around bar in the butt of a stock. Bought the tungsten from McMaster-Carr and the lowest grade was $150 for a 4" piece.
I don't know what you plan to do with this gun or what kind of accuracy you're looking for. but it does look like you're serious about what your doing. A few thoughts on your ammo testing. Forget the CCI stuff. One of the least accurate most inconsistent ammos being produced today. The CCI group is not good considering the quality of your build. It contains every problem you can encounter . Fliers, windage and elevation stringing. Your other two groups show potential. But remember this! It's not the name on the box a gun likes it's the lot number.
I've had good results with CCI-SV in several rifles, that were on par or better than SK Rifle Match in those. The problem is trying to run CCI-SV in a tight chamber, which is what actual match grade chambers are. I've seen some videos of people having acceptable "practice" results using CCI-SV in Vudoo and RimX, but I'm not going to put it in mine...for the same reason you don't run 87 octane gas in a race car.
One thing That stands out on all your groups is the excessive amount of vertical. A tuner would probably eliminate most of it but there are a couple of things you might look before spending money on a tuner. One is playing with action screw torque settings. the other is forend pressure when you shoot and bipod placement. All 3 can effect vertical shot placement. Also after looking at your gun again it looks like you may be shooting suppressed. If you are, suppressors can effect accuracy. Most of the time in a negative way!
In these times where 22LR match ammo is scarce and expensive I would drop the coin for an ATS tuner. You can tune and still run suppressed and I've seen good results posted. I just got one myself but haven't had a chance to hit the range with it.
Any tuner... I personally prefer and have the EC tuner which sits further forward on a threaded barrel and weigh ls almost twice as much overall.
Have a some buds that use the EC and I know they are good ones. My only recommendation for ATS is I can still use my can in front of it.
In its standard form with adapter no, but on a match 22lr I wouldn't use a can or brake. You could have your barrel spun to incorporate the EC Tuner with exposed threads to do it. My next barrel will be milled for one with exposed 11 degree. crown. I've run both the EC and ATS nothing wrong with either as I said just a preference for my 22.
