Our very best shooters (all of which are also exceptional TR shooters out to 800m) can put ten rounds into under 2moa, during the slow course of fire (either deliberate or application) from prone at 300m, using a factory front blade sight and a rear peep, and a service sling like the m1907 sling or USGI web sling. Obviously they do slightly better with a front tunnel for Palma matches, but only slightly.
Everyone has completed the slow course after approx 2 minutes of shooting. Sub 2moa can yield a perfect integer score, aka a possible. With such skill, it
should be possible to also group into the V, and get a perfect decimal score, alas take windage into consideration, and almost certainly decimals are dropped. That's essentially the same outcome as the top High Power shooters in the US, like Konrad. if you clean every course during a multi-stage, without dropping an integer, you will go close to winning overall.
A scope will bring the group in a bit, more importantly make it more circular. As analysed here:
https://youtu.be/ffuGpz1ZsD8?list=TLPQM ... ctXfkBeFEASo in our context, the difference between a sub-moa gun and say a 1.5 moa gun is fairly insignificant, so long as the rifle is
consistent. Consistency is king.
From standing offhand (distances), you are above average if you can put all your shots into sub 4moa. I mean
all your shots, under match pressures, consistently. The best shooters are going sub 3moa, and will go close to shooting a perfect score if they can hold that.
I've heard high-power MS shooters claim they are "sub-moa accurate" from standing offhand, but if they somehow recorded all 40 shots from their match, particularly including the 500m rams, I bet their group would be significantly larger than 1moa. Granted they have the luxury of taking the weight off their arms, which would help. Personally, I think a 1.5moa grouper is perfectly competitive for HP-MS.