Mag rifle vs match grade primers

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JPrawn

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Been working out loads for my 7 mm wsm and finally got some shooting sub moa. Fired about 12 with the “Labradar” and it averaged 2820 FPS. Couple shoots later we had the labradar out again so I tried a few more and velocities had jumped almost 100 Fps. Racked my brain a bit to realize the last batch loaded was with match grade magnum primers vs standard magnum primers. Wondering if that would make that much difference or if I screwed up something else while loading the last batch? (Like 64.2 grains of powder vs 62.4). hmmm....
JP
 
Depending on what powder you are using, this difference in velocity could easily be the result of a primer change. Perhaps of more importance, how did the primer change affect the extreme spread and the consistency? If in doubt, try both loads again on the same day.
 
In my results I see almost no speed/pressure variation from standard to magnum primer in a 7mm Rem Mag. At least within the same brand

Not the most in depth test, but decent sample size. 90 rounds fired, 45 with CCI 200 & 45 with the 250 Magnum primer, in 3 differet temps (-15c, +13c, and +29c), 5 different powders (IMR 7977, IMR 4831, RL23, RL22 and H4831sc)

average velocity - CCI 200 = 2790 fps, magnum primer = 2795 fps

standard primer gave 18% better velocity variation too, even in cold weather
 
The only reason I now load with match grade primers (Federal) is to reduce the number of fliers I get in a batch of bullets. I do not measure my speeds very often so I cannot comment on that aspect but I would assume they should not give you any more or less flash to start with. Just be more consistant over a spread of bullets. While I would agree that moving to a different brand of primers could certainly change the speeds and results, within the same brand you should not see much of a difference.

My prices for gold match grade federal primers is only about $15/1000 difference so that works out to 1.5 cents a bullet different in cost. I am willing to pay that to have less fliers and perhaps more consistancy.
 
B said:
Match primers are typically very "hot".
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I'm not so sure about this....
I asked CCi a few years ago about their BR-2 primers. The response was that the BR-2 primers were the ballistic equivalent to the #200 LR primers, just held to a tighter tolerance in manufacturing.
 
JPrawn said:
Been working out loads for my 7 mm wsm and finally got some shooting sub moa. Fired about 12 with the “Labradar” and it averaged 2820 FPS. Couple shoots later we had the labradar out again so I tried a few more and velocities had jumped almost 100 Fps. Racked my brain a bit to realize the last batch loaded was with match grade magnum primers vs standard magnum primers. Wondering if that would make that much difference or if I screwed up something else while loading the last batch? (Like 64.2 grains of powder vs 62.4). hmmm....
JP
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I was doing some reloading for my 7rm using H1000 and for a 300wm with the same powder. My loads was getting up there close to 70-80 gr of H1000. I figured maybe I should be using the “magnum “ primers. I went from very good 1/2” Mia groups using match large rifle primers to horrendous groups using magnum match large rifle primers. Both calibers. It didn’t matter what I did with the load either. They just plain sucked. Both were Federal and both were match.

Went back to non magnum primers and all was back to normal. So there is that.
 
Federal match mag primers and my 300 SAUM work great with IMR 4350 and 175 gr. Berger hybrids .27 group
 
GMHVAC said:
I was doing some reloading for my 7rm using H1000 and for a 300wm with the same powder. My loads was getting up there close to 70-80 gr of H1000. I figured maybe I should be using the “magnum “ primers. I went from very good 1/2” Mia groups using match large rifle primers to horrendous groups using magnum match large rifle primers. Both calibers. It didn’t matter what I did with the load either. They just plain sucked. Both were Federal and both were match.
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Did you measure the change in velocity between standard and magnum primer?
 
I did a ladder test with IMR 7828 in my .270win with Hornady SST. Nothing shot well. So I did the test again with federal 215 match magnum primers and boy oh boy it really liked that. Major improvement across the board.
 
Thanks for everyones input. Unfortunately out of time to continue load development before I go sheep hunting in two weeks, so I'll be taking my new Tikka in 7mm-08 instead. Had a good load made up for that but was using factory federal brass and it started separating after 3 firings so I ran out of brass. It is shooting consistent 2" groups at 200 yards with factory Winchester 140 grain ballistic tips so that will be it for now. Will update when I get back from the hunt and can do some more work with the WSM. I would REALLY like to get that one shooting sub MOA consistently.
Thanks again.
JP
 
OldDude said:
I'm not so sure about this....
I asked CCi a few years ago about their BR-2 primers. The response was that the BR-2 primers were the ballistic equivalent to the #200 LR primers, just held to a tighter tolerance in manufacturing.
Click to expand...

Not only that; CCI primers are notoriously mild compared to many other makes.
 
Dogleg said:
Not only that; CCI primers are notoriously mild compared to many other makes.
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I never said it was a given but if you pay attention to anecdotal lists of hottest primers you can find the top populated mostly by various match primers. The Rem 7.5 is probably hands down the hottest SR/SP size primer available. I use it for .357 and .454 using huge charges of H-110 and it seems to make a big difference.
 
I'm surprised nobody asked about ambient temperature between the Labradar experiences. Unless you're using a temp stable powder like Varget, 100 fps differences are very common with ambient temp changes. I've seen larger spans between winter and summer.
 
JPrawn said:
Been working out loads for my 7 mm wsm and finally got some shooting sub moa. Fired about 12 with the “Labradar” and it averaged 2820 FPS. Couple shoots later we had the labradar out again so I tried a few more and velocities had jumped almost 100 Fps. Racked my brain a bit to realize the last batch loaded was with match grade magnum primers vs standard magnum primers. Wondering if that would make that much difference or if I screwed up something else while loading the last batch? (Like 64.2 grains of powder vs 62.4). hmmm....
JP
Click to expand...

I've tested Fed. 215M in my standard Fed. 210M loads and never experienced a significant difference in velocity. It could be a number of factors for your higher velocity: additional powder, different powder, labradar was inconsistent, warmer daytime temperatures, etc.
 
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