Previously discussed the use of magnum primers in my 1898 Krag rifle which has a Criterion match barrel, .308" bore and a 1 in 10" twist.

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This weekend I tested 5 different standard primers at 200 yards using a standard 200 yard CMP Slow Fire target.  The loads were all with the same: 40 grains IMR4350 behind a Hornady 220 grain RN.  The primers included in the test:
a. Winchester Large Rifle
b. Remington 9 1/2
c. CCI 200
d. CCI BR-2
e. Federal GM210 Match

I loaded 10 each crimped and 10 each uncrimped.  Shot 5 of each type this weekend and my plan is to Chrono the others to confirm my results with hard data.  Some observations first:

a. The groups using crimped bullets (Lee Factory crimp die) showed more not less vertical stringing.  Almost without exception I'd get a tight cluster of 3 with one high and one low, or with two high or low.

b. The groups with uncrimped bullets rarely had high or low shots, but the clusters of the shots were not quite as tight

c.  With one exception (CCI BR-2), the crimped loads always shot a minute of angle or two higher than the uncrimped loads.  The BR-2 shot to the same basic POI.

Based on the results so far I'd make the following load decisions.
a.  No crimp
b.  Winchester LR primers first choice
c.  Remington 9 1/2 second
d.  CCI BR-2
e.  CCI 200
f.  Federal GM210M Last choice

I have pictures of all the targets if you guys think there is any value in posting them.

Keith

Thanks also for the research. I have always used Winchester primers because I started with my father's leftover stuff. Now I have another reason.