So has anyone done a side-by-side comparison shooting test with an old Mini 14 [.223] and one with the new "heavy" barrel?
Is accuracy improved with the new ones? REALLY?
Would love to know about this.
Yes, the new heavier barrels will shoot better. They do not string anywhere near as much as the thin barrels do. You should be able to get 1.5 inch groups with good ammo with the heavier barrels.
The thin barrels can be made to shoot much better with the addition of a support strut. I hope to be posting pictures of my struts that I will have for sale within a few days. They work just as well as the commercial one's at less than half the price. They are pretty darn good looking also.
If your looking at buying a Mini, a new one would give you good groups without any work.
If you find a good used thin barrel Mini for a low price, it can be made to shoot. My thin barreled mini shot a best 3 shot group of .474" and 5 shot group of .855" at 80 yards. One flyer opened up the 5 shot group and it was the last and only 5 shot group I fired that day; I ran out of ammo. I'm not sure if it was me or the weapon. The 100 YD range was full so I couldn't shoot at 100 like I would have like to.
It was a clear, windless day and the rifle was shot from a rest on a cement shooting bench.
The Mini 14 was modified with a steel bedded action, a strut, trigger job, Mason flash hider/brake combo, 3 X 9 Nikon scope and a re cut muzzle using 55 grn factory ammo. It is an older 187 model with the 1-10 twist barrel. It also had very few rounds put through it, so it was a new, older rifle.
I can show some pics comparing a 195-series (ss ranch rifle) to a new all-weather ss series 581. Unfortunately, I've misplaced my measurements. But you can get an idea of what has been changed. The overall contour is quite different, and the new barrel is larger in the cylindrical portions, i.e. the thinnest parts.
Here is the overall comparison. Notice particularly the new cone shaped region in front of the gas block, and the extra middle step in front of the chamber.
Detail of the chamber region:
Detail of the gas block region. I think this cone acts as a stop to prevent the barrel from sliding in the gas block due to recoil.
I haven't done any accuracy testing, but the new barrel looks as though it should be better.