I have been doing a couple of hundred strikes with popping out the inserts on $10 strikes. And for fun I have been weighing the inserts. I have found that the strikes that are suppose to be .5 I have found some as low as .48 and as high as .51. And as for the inserts that are suppose to be .6 I have found them as low as .58 and as high as .61 .

Dennis