Bullet length variation

[nell]

Hi guys, i have noticed for some time that when mesuring conpleted rounds using a stoney point bullet comparater that if i rotate the round whilst in the caliper the reading can change by as much as 2thou, does anybody else notice this????? and concider it a problem???

I have started load development for my 6mmbr, the accuracy of this gun is somthing im not used to, whilst going through the barrel break in the 1st 5 shot group i fired made a small jaggy hole, so have high hopes.

 

RGS

NELL

[Elwood]

I rotate all my my rounds gently the same as you have, I find this gives me a correct reading. Not all bullets have a perfect measurment even to the ogive, so personally I wouldn't be to be bothered.

[Redfox]

Using a vernier caliper and rotating the complete round will give variation due to the case head moving about in contact with the jaw, it is not likely to be the bullet ogive which is the variation.

Using any sort of hand measuring instrument is an aquired skill which is gained after quite a lot of practice, so I would not worry too much about it at this stage. People who do this for a living become very sensitive to the feel of the item being measured and get to know when it is consistently in the same position.

Generally the shortest overall reading will be the correct one, once you can find this point on each round you will be on your way. Ian (vermincinerator) on here was a quality controller in the engineering industry and can help you on this as he has done a great deal of it.

Redfox

[nell]

Thanks for replies guys, i was never in very much doubt that it was the case head that was causing the difference, as you state REDFOX i can feel this grinding on the calipre jaw as i rotate the round.

NELL