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.

  (You need to Login

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

Keith - Thank you for your experimenting and sharing results and conclusions.

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.

After doing the initial 200 yard comparison test on Nov 8, I made the following recommendations:
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 followed that test up with another 200 yard test on Dec 13 and have verified several conclusions but have changed which primer I believe gave me the best results:
a.  No crimp.  The second test validated in glaring Technicolor that in my rifle using a crimp significantly increases vertical stringing.
b. Remington 9 1/2 primer gave the best performance of both tests combined.
c. CCI BR-2 second
d. CCI 200 third
e. Federal GM210M fourth
f.  Winchester Large Rifle last place

At first glance some of you may take issue with my conclusions since WLR went from first place to last.  The reason was my conclusion was based on a combination of how the primer performed in a crimped and also a non-crimped cartridge.  Now however I've decided to discard all the data obtained from the crimped cartridges.  The performance is so poor as not to be relevant.  So, using just the non-crimped cartridge performance the Remington is the clear winner.  Here are the groups from Nov 8 and Dec 13:

  (You need to Login
  (You need to Login

Based on how difficult the sighting system on the ladder sight is to use, I fully accept that the lone high shot in each group is my fault and not the load's.

Keith