Magnum Primers?

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BOB567
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Magnum Primers?

Post by BOB567 » Tue Nov 19, 2019 10:17 pm

Sorry, I tried searching the word primer and got 437 pages. After about 15 pages I gave up. Downloaded Hodgdon's data for the 300 Blkout Their specs call for magnum primers. Do you all use magnum primers? I plan on using H110, W296, & CFE BLK. Probably some tight group and other pistol powders for subs.

I guess I just thought companies would recommend standard small rifle primers. What do you all use? Why?

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eowen37
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Re: Magnum Primers?

Post by eowen37 » Tue Nov 19, 2019 11:20 pm

I use regular winchester small rifle primers. Works great with vihtavuori n110 & n120 powders. Both put down sub moa groups.

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bangbangping
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Re: Magnum Primers?

Post by bangbangping » Wed Nov 20, 2019 12:05 am

I have found more consistent results with H110/W296 using magnum primers. With subs, no. Haven't tried CFE BLK.

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dellet
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Re: Magnum Primers?

Post by dellet » Wed Nov 20, 2019 12:59 am

In theory small rifle primers were designed for lower pressure loads up to 40,000 psi. They have a thinner cup than magnum primers. A fair amount of people use them with good results I wouldn’t in hot loads.
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Dr.Phil
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Re: Magnum Primers?

Post by Dr.Phil » Wed Nov 20, 2019 9:52 am

dellet wrote:
Wed Nov 20, 2019 12:59 am
In theory small rifle primers were designed for lower pressure loads up to 40,000 psi. They have a thinner cup than magnum primers. A fair amount of people use them with good results I wouldn’t in hot loads.
To elaborate on this, dellet says this due to it masking pressure signs and changing the pressure curve.
(This is due to a thicker primer cup.)

Cartridges like the 6.5 Grendel call for a SR Mag primer.

2 Reasons to use SR Magnum primers, more complete powder burn, earlier in the cycle and thicker primer cup.
Oddly enough, subsonic 300 BLK can benefit quite a bit from SR Mag primers due to the low case fill of faster burning pistol powders.
(In general, the faster the burn rate of the powder, the quieter the sub load will be.)

I have come across folks that use Magnum Primers as a way to either save powder or get higher velocities from a compressed load.
IMO, this is NOT a good practice.
It is viable if you are an experienced and competent hand loader, but due to the stacking effect that switching to a MAG primer can make, it will often create many more issues than it solves.
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don't tell them where they know the fish."
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dellet
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Re: Magnum Primers?

Post by dellet » Wed Nov 20, 2019 10:46 am

Dr.Phil wrote:
Wed Nov 20, 2019 9:52 am
dellet wrote:
Wed Nov 20, 2019 12:59 am
In theory small rifle primers were designed for lower pressure loads up to 40,000 psi. They have a thinner cup than magnum primers. A fair amount of people use them with good results I wouldn’t in hot loads.
To elaborate on this, dellet says this due to it masking pressure signs and changing the pressure curve.
(This is due to a thicker primer cup.)

Cartridges like the 6.5 Grendel call for a SR Mag primer.

2 Reasons to use SR Magnum primers, more complete powder burn, earlier in the cycle and thicker primer cup.
Oddly enough, subsonic 300 BLK can benefit quite a bit from SR Mag primers due to the low case fill of faster burning pistol powders.
(In general, the faster the burn rate of the powder, the quieter the sub load will be.)

I have come across folks that use Magnum Primers as a way to either save powder or get higher velocities from a compressed load.
IMO, this is NOT a good practice.
It is viable if you are an experienced and competent hand loader, but due to the stacking effect that switching to a MAG primer can make, it will often create many more issues than it solves.
Not to confuse the issue, but.......... :P

Some of my low density, fast powder loads for some of the antiques I shoot, the primer of choice is a standard small pistol primer. They work really well in small cases like 22 hornet as well.

Safely experimenting is what makes handloading fun.
300 Blackout, not just for sub-sonics.

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Dr.Phil
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Re: Magnum Primers?

Post by Dr.Phil » Wed Nov 20, 2019 2:18 pm

dellet wrote:
Wed Nov 20, 2019 10:46 am
Not to confuse the issue, but.......... :P

Some of my low density, fast powder loads for some of the antiques I shoot, the primer of choice is a standard small pistol primer. They work really well in small cases like 22 hornet as well.

Safely experimenting is what makes handloading fun.
To add even additional confusion, some use Magnum PISTOL primers... :shock:

One other unintended consequence of Magnum primers is bumping the projectile into the throat prior to pressure fully obturating the brass case.
"Don't tell fish stories where the people know you; but particularly,
don't tell them where they know the fish."
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Re: Magnum Primers?

Post by rlandry6 » Wed Nov 20, 2019 6:20 pm

To go Magnum or not also depends on the manufacturer. CCI is the only one I have run across that designates between regular and magnum primers. Winchester does not, neither does Federal.
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Re: Magnum Primers?

Post by 308loader » Wed Nov 20, 2019 8:16 pm

wait, so my federal 215 primers (large rifle mag) are just the same as normal federal LRP? the box lied to me? I want my money back!

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Re: Magnum Primers?

Post by golfindia » Wed Nov 20, 2019 9:22 pm

Rem 7.5 is a bench rest primer according the side of my boxes. Why does hodgdon call it magnum?

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