Marco, I can't say without a doubt it has a 308 barrel. I'm actually reasonably sure its closer to 309. No I have not slugged the barrel. I have, however, read the manual which states it has a 308 barrel but can accept 311 it will lower bore expected lifespan.
Just to ease your worried mind on that aspect...century also owns its own ammunition company (i forget if its red army or one of the other smaller name steel jacket companies). It was produced to shoot in the century arms ak and it has a diameter of .310
Without actually slugging the barrel, I have to go with what I'm told
by the manufacturer.
I'm not really concerned with an exploding gun. I have shot .311 ammunition out of it before. If the barrel was made proper and it seems to have been, I should have zero issues with that.
I am more worried about the unknown factors. Size just isn't one of them in this. If I lower the start load too much it might have adverse effects as well.
Lee calls for a 10% drop from published start load to begin with. But that is for a .311 bullet.
There is still .001 to play with. You can get pressure spikes from too little powder too.
So that means :
Published start load is 23.6 gr
10% below that is 21.2
5% is 22.4
Which is the closer answer to the question at hand?
I know that .310 bullet dia is not too big for it to accept. Its how hard do I punch it thru