From what I have seen from various testing larger FH up to a point actually showed improvement. But that depends on where the starting point in. I know for the 308 case it started @ 2mm with a certain manf and the best accuracy was found @ 3mm yet vel/press changes were only 2% but accuracy from smaller than spec to larger was 20%.
The main thing that would keep me from wanting to change FH sizes is the accuracy you have already been getting. I do not how many groups I have seen in the .1s. Still something to discuss with Bertram. I would say ask him if he could send you say 10 case prototypes for 6.5ss and then work up loads and see what the groups and es sd looks like and go from there. If its worse then ask to have the norma fh size used.
we also need to know what each size fh actually
To me if held at a certain powder column length I would think a primer flash you want to expose a certian % of the powder column. That means a wider powder column such as the short mags could stand to have a FH larger than say a 308.
In some of test results I saw that were posted on the net with high speed film increased size did not have a neg effect on the length of the flash but did increase the width of it. I know some had hoped a small fh would create a funnel effect but it did not seem to from the results I read.
But I did not spend hours an hours researching it deeply.
The main thing that would keep me from wanting to change FH sizes is the accuracy you have already been getting. I do not how many groups I have seen in the .1s. Still something to discuss with Bertram. I would say ask him if he could send you say 10 case prototypes for 6.5ss and then work up loads and see what the groups and es sd looks like and go from there. If its worse then ask to have the norma fh size used.
we also need to know what each size fh actually
To me if held at a certain powder column length I would think a primer flash you want to expose a certian % of the powder column. That means a wider powder column such as the short mags could stand to have a FH larger than say a 308.
In some of test results I saw that were posted on the net with high speed film increased size did not have a neg effect on the length of the flash but did increase the width of it. I know some had hoped a small fh would create a funnel effect but it did not seem to from the results I read.
But I did not spend hours an hours researching it deeply.
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