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Old 09-19-2019, 01:21 PM
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huntschool

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Quote:
Originally Posted by joet333 View Post
I modified my rimfire gauge to measure the ogive length from the base of the rim, and sorted several lots of Eley, Hornady, and CCI (.17M2) into consistent groups.
I found that for my Kimber K17 ProVarmint there was a certain ogive length that gave consistently smaller groups with no fliers. Within any given lot the ogive length could vary by as much as .016" due to seating depth. This is considerable and points to the lack of quality control in these rounds. Hence no "match grade" ammo is available for .17M2 (and probably for .17HMR) simply due to variations in bullet seating depth, as well as other factors. One cannot measure the OAL with any meaningful results because the little plastic V-tip dimensions can vary by .010".
In my testing, the best sorted ammo lots made 5-shot groups at 50 yards as small as .377" while the same lot with different ogive lengths shot as poorly as 1.301".

I don't claim that sorting can make match grade ammo, but it did eliminate the fliers, at least for my rifle. Other rifle chambers may not be as sensitive as mine to variations in ogive length.
joet333:

Thanks for the link. I dont know why I did not think of that. Old brain I guess.

So, to make the "short" of it (no pun intended) if one could only measure and sort by OAL the longer cartridges may well prove to be the better performing loads. Would that be a very simple analogy to your testing ? Knowing that there are surely some other factors at play.

Thanks
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