yodar,
Thanks for your reply... I was asking about your overall bullet length because of the 155 gn weight you mentioned. The bullet that is made for it is lighter and I was thinking maybe shorter than the one you were making for it.
So I also asked for the twist to see if your large groups were due to not stablizing the weight and length of the bullet.
The weight could be heavier because of the property you are using and if they were made with another then the configuration is going to be different.
The tapering of the points in the original allowed it to feed well. The design of the bullet (in picture) is not a true spitzer. It is more like a round with a slight point to it.
I would figure yours are not a boat tail design, which means it might be the same length, but more of the bullet is touching as it is moving down the barrel, which would account for a different amount of accuracy with the bullet.
I have some 122 grain hollow point ammo that is/was made in Russia.
The weight difference is 33 grains less. So I am sure it is moving at a much higher velocity. I don't know if you have chronographed your stuff, but I'd say it is closer to 1600 than 2000 fps.
http://en.wikipedia.org/wiki/7.62x39
According to some the bullet designed for the russian manufacture was for feeding purpose also.
It is getting complicated, but your bullet would me slower and maybe not feed as well, have you had any signs of that being a problem?
http://www.conjay.com/Ammunition for Armor Testing East 7.62mm x 39.htm
Regards.