1941 Winchester .303

[togor]

What's wrong with a two-groove barrel? Is it rusty or shot out? If it isn't, and passes the gauging standards, it should perform every bit as well as a five or six groove barrel. They wouldn't have been adopted if they performed worse than other barrels. The same holds true for the 1903A3 Springfield and other military rifles.

Two skinny channels into which jacket material has to move in order for meaningful twist to impart upon the projectile. With BT bullets, there is insufficient contact area for that to happen. One has to have bullets that are both flat base AND open base to hope for meaningful engagement.

These Winchester bullets have that which is why I bought this ammo.

I have some modern 180gr SP with a flat (but closed) base. I will also see how they do.

In an 03A3 the groove/land ratio is about 50/50. In the No. 4 2-groove it is about 10/90.

The No.4 5-groove rifling also appears about 50/50.

It was a wartime expedient so I'm not hating on the production people. It was on the winning end of the war and did its part. But that doesn't make the No. 4 2 groove a great performer in 2025.

On the plus side it's a fun challenge to overcome the various obstacles.

[browningautorifle]

One has to have bullets that are both flat base AND open base to hope for meaningful engagement.

But that WAS the bullet design at the time. They didn't consider us 80 odd years onward.