Lilja bbl CZ
At the US Army Marksmanship Unit we sent ammo technicians to Europe and Scandinavia to buy rimfire ammo in lots. The only way you can proof it is by shooting it.
Our acceptance standard was 12mm or smaller 10-shot groups at (I believe) 50 Meters through barrels from Anschutz, Krieger (cut-rifled), Lilja, and a number of other brands.
This ammo supports rimfire 3-position shooting under International Shooting Sports Foundation (Olympic format), NRA, and NRA 100-yard prone rules.
I don't want to hijack the thread but Sinister's report of ammo testing for selection of 22lr match ammo piqued my interest. You mentioned Europe and Scandinavia to test ammo. Would you please give us some more info about those tests? Which brands were being tested (i.e. Lapua, Eley, Olymp, RWS, etc. and how did they stack up? You described some premium barrels used for testing but did not describe the firearms. Are we talking about custom match rifles like a Turbo or Hall or Factory rifles with custom bbl's like the CZ-Lilja combo or a Rem 40x with match bbl?
I just wanted to get a little more context into the comment as well as learn what sort of equipment your test technicians were using and the test methods. i.e. complete firearm fired from sandbags? complete firearm fired from prone with sling? complete firearm clamped into a machine rest or a test barrel clamped into a test jig? I was asking as I was told how some Olympic shooting sports teams come to Eley to test ammo lots and use a clamping machine rest so point of aim is the same each shot and they shoot at an indoor facility so wind is not a factor. Each uses their competition rifle so the ammo is matched to the gun. Some of my BR shooting friends test ammo lots but do it under the same conditions we plan to compete in. i.e. Complete rifle fired from 1 or 2 piece rest outdoors.
Based on what I have seen with custom BR guns compared to high quality factory guns shooting at 50yds,for example: my factory Remington 540XR is capable of shooting an IR50/50 tgt scoring a 248/12x. It will not do that every time. Runs 243 to 248 most of the time. I shot a string of 25, five shot groups in a row onto a single USBR tgt last week with it. Ammo was SK std plus, Eley Black and Wolf Match Extra, with about 1/3rd from each. Best group was 0.217" (5.5mm/0.415 MOA) with average for all 25 being 0.349" (8.9mm/0.666 MOA). Not great but very representative of what it is capable of at 50yds shooting from a 2 piece rest, with good but not the best ammo. A custom Turbo action with Jewel trigger, and Shilein bbl using 36x optic from a 1 piece micrometer rest shoots IR50/50 tgt (same day & conditions as me) scoring 250/20x (match winner), using Eley Black ammo. Some of that is more experienced shooter and some is rifle, rest, etc. Some of it is the barrel. How much? That rifle will print groups that are averaging 0.224" or a fraction larger for 25 shots in a row with aimed fire in outdoor conditions. That is the worst it can shoot and score a 250/20x on the IR50/50 tgt. A Hall action with Rock Creek bbl jewel trigger and Night Force tgt scope shoots about the same as the Turbo. Another Turbo with Lilja bbl shoots better than the other two and has scored 2450pts on the ARA tgt. All those were using Eley black. There are not many factory actions that will shoot that well regardless of the bbl they are fitted with. Too many other variables in the fit and finish of the bolt, receiver, ignition system, etc. The gunsmiths who will be honest with us will tell us that even with a stack of 20 match grade bbls, there will only be about 10% of them that are really great, with the diameter tapering down from largest at the breech to smallest at the crown. You might want to slug your CZ bbl and see what you have now before removing it.
Based on what the OP is getting with his gun already, he might see a small improvement with a well fit Lilja bbl. Would likely see some groups that are .250" at 50yds, some may even be better. The average for a long string of 5 or 6 groups is not likely to be that good. But that should get him to a close to 1/2" or slightly bigger at 100yds? The longer the distance the more the environment, wind, temp, humidity begins to affect results. I would guess average of 0.600 to 0.800 MOA. We have seen CZ/Lilja's that will shoot better than that. It really will come down to whether you get one of the killer barrels or one of the 90%. I give you a 10:1 chance.
Irish