Magnum Primers = higher velocity?

Hypnogator · Jun 30, 2014

I'm working up some "serious social occasions" loads for my ARs, using 60-gr Nosler Partition bullets. I've always had good luck loading with CCI 400 primers, but am not getting quite the velocities I'm looking for out of my 16" bbls. I'm wondering if using CCI 41 or 450 primers will ignite the powder enough quicker to boost the velocity out of a 16" barrel.

Anyone have any experience measuring the difference in velocity between the two types of primers, when other load data is the same?

BTW, I've never had problems with pressure signs from the 400s, but am a bit leery of the 41s, as I've read that they may have ignition issues on occasion.

Thanks, all!

Blue68f100 · Jun 30, 2014

The most gain you will probably see is ~10-20fps max. With new lots of powder, some times you have to bump the loads to match the velocity. But different volume in brass has more impact than primers with the same powder charge.

ArchAngelCD · Jun 30, 2014

You didn't tell us which powder you're using. Some powders are helped by the use of a magnum primer, some are not.

BTW, I've never had problems with pressure signs from the 400s, but am a bit leery of the 41s, as I've read that they may have ignition issues on occasion.

A magnum primers will not create a nuclear explosion. They only burn a little longer and a little hotter to insure proper ignition with hard to ignite Ball Powders and very large powder charges like in big Magnum cases.

mdm · Jun 30, 2014

What velocity are you getting now?

In the velocity vs. accuracy debate, accuracy will normally win for me.

Higher velocity just for the sake of higher velocity is usually just a waste of powder.

jwrowland77 · Jun 30, 2014

I'm with mdm on this. Accuracy always trumps velocity.

Only on one occasion have I chased velocity AND accuracy, and that was for a 1000yd match load.

What is the powder you're using? You might be able to achieve your goal with simply changing powders.

Magnum primers are perfectly safe to use and as said, won't cause a nuclear explosion. Just back off your load a bit and work back up.

Really what it sounds like though, is you're in need of a different powder.

edfardos · Jun 30, 2014

Speer data for h335 calls for mag primers.

45acp with 230grain bullet and win231, i see an extra 30 fps with mag primers.

jmr40 · Jun 30, 2014

With this specific load I don't know.

As a general rule magnum primers usually give a little more pressure, which means a little more speed. There are 2 problems. If you're already at a max load changing to magnum primers could push you into a load that is too hot. If you are not at a max load, adding more powder will usually do the same.

The other issue is that not all primers are the same. It is not unusual for some non magnum primers to be hotter than some magnum primers.

I know that in some cases reloaders have gone to a magnum primer, reduced the powder charge and improved accuracy with no loss in speed. Just have to experiment.

NCsmitty · Jul 1, 2014

You can play around with primers and powders and different loads but the limiting factor is your 16"barrel. You would likely see instant gratification with a 20" barrel.

NCsmitty

Hypnogator · Jul 1, 2014

FWIW, I'm averaging 2825 FPS with a 62-gr SS109 bullet and 26.5-gr Varget, and 3046 fps with a 55-gr V-Max bullet on top of 25.6-gr AR-Comp.

Doesn't look like I could cram much more Varget into the cases, as I have to tap the sides of the case with the mouth under the powder measure to settle the powder as is.

The AR-Comp gives a little more leeway, but pushing it to 26.0 gr doesn't add significantly to the velocity, and at that point the 400 primers are starting to flatten.

Yeah, a 20-in bbl would offer a significant increase, but at a penalty in portability and handiness. I'm trying to see what I can accomplish with my 16" carbines. BTW, have found the Varget load scary accurate with 60 & 62-gr bullets. The most accurate load with AR-Comp was 25.0 gr under a 55-gr V-Max. Averaged 2931 FPS with an astounding 3.21 SD.

Steve C · Jul 1, 2014

There is no rule regarding velocity from magnum primers. Sometimes the velocity is greater and other times it is less when compared to a standard primer. You will see greater changes in velocity by changing brand of primer than simply switching to a mag primer. The only thing I usually see is a smaller standard deviation IE variation in velocity readings when using mag primers though this doesn't translate into a noticeable improvement in accuracy.

Magnum Primers = higher velocity?

Hypnogator

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Blue68f100

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ArchAngelCD

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mdm

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edfardos

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Hypnogator

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