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Discussion Starter · #1 ·
What effect can different primer's have on a load? Presuming your using the correct size, do different brands of primers really make a difference with the same powder? (i.e Remmington, Winchester, or CCI's effect on Reloader #7)

And can you tell the difference if you don't have a chronograph?
 

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What effect can different primer's have on a load? Presuming your using the correct size, do different brands of primers really make a difference with the same powder? (i.e Remmington, Winchester, or CCI's effect on Reloader #7)

And can you tell the difference if you don't have a chronograph?
If your already loading to the max where pressures are concerned, it could have a really major effect. A magnum primer could bump your pressures.
Some powders respond better with better ignition. A mag primer or different brand of reg primer could cause a faster combustion rate, that'd bump the chamber pressures.

As far as telling the difference, a chronograph and existing load data before the primer change, as well as watching for pressure signs, may be the only way to tell the difference.
 

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Discussion Starter · #3 ·
Thanks!

Katkt, I ask because I'm just starting to reload. I was going to try different powders and primers but without a crono, (and lacking super human vision) the only reference point I'll have will be my group's and looking at my cases So I'll probably just buy a block of CCI Military Large Rifle and be done with it! I'm not getting close to "maxium loads" for now. Remember I AM A NEWBE. That is until I can get a crono, and bring some real science to it.

For my Mini 30, I'm using IMR 4198 and Reloader #7 and load data from Steve4120, and CTSixshot, and MC45. As well as from all the manuals I've picked up over the last couple of weeks........ So for now I'm going to jump in and and start pulling the handle! But I'd thought I'd better post the question to confirm my suspicions. Thanks!
 

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Katkt, I ask because I'm just starting to reload. I was going to try different powders and primers but without a crono, (and lacking super human vision) the only reference point I'll have will be my group's and looking at my cases So I'll probably just buy a block of CCI Military Large Rifle and be done with it! I'm not getting close to "maxium loads" for now. Remember I AM A NEWBE. That is until I can get a crono, and bring some real science to it.

For my Mini 30, I'm using IMR 4198 and Reloader #7 and load data from Steve4120, and CTSixshot, and MC45. As well as from all the manuals I've picked up over the last couple of weeks........ So for now I'm going to jump in and and start pulling the handle! But I'd thought I'd better post the question to confirm my suspicions. Thanks!
As long as your staying under your maximums a ways, you'll be fine tinkering around. Everybody throws out the qualifiers, so people will be carefull, and think about all the different things that affect pressure. Just watch for the pressure signs on the stuff you load.

I talked to another guy on a different site awhile back when I was having problems because I wasn't de-crimping my primer pokets well enough, and had some failures. At first, I thought it was a primer problem. Then,....like with most things I found out it was me.:D
He loaded alot of stuff for Mil surplus rifles, for competition etc., and said that all he uses anymore are the CCI mil primers. Git-r-done.:)
 

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Primers can make a difference, but it's the last thing I worry about when searching for that magic load. Unless I am dealing with a good sized case with a compressed charge, then I start out testing with standard and magnum primers at the same time.

I ran a little test a few years ago with my CZ 221 Fireball and different primers. Here is what I came up with.

I worked up a bunch of loads with 14.8gr 2400, 40gr BT's and Vmax with 4 different primers. WSR, 7 1/2, 6 1/2 and Fed 205Ms 15 rounds each. Here is what I came up with at 100 yards three sets of 5.

Fed 205M NBT's avg velocity 3284fps, .786in group. Vmax, 3291fps, .544in group.

Rem 7 1/2 NBT's 3311fps, .643in group, Vmax 3322fps .507in group.

WSR NBT's 3404fps, .332 in group. Vmax 3398fps .298in group.
 

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Discussion Starter · #6 ·
....He loaded alot of stuff for Mil surplus rifles, for competition etc., and said that all he uses anymore are the CCI mil primers. Git-r-done.:)
But don't you have to reduce the load? CCI says they are to be considered as Magnum primers. And for my Mini 30, all the load data I have found so far, only lists "Larger Rifle" primers. And even I know that the magnum and Large rifle primers aren't "interchangeable". Right? (See how sure I am :huh:)
 

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Steve will straighten this out if I screw up.:D

Generally speaking, regarding rifle cartridges,......excluding exotic this or thats...... there are two different size primer pockets...large, and small.

The magnum part refers to the ignition material that is used. It is the same size primer dimensionally, it just makes a bigger bang when it goes off. This is what causes pressures to creep up. In a smaller rifle case, with less powder, a magnum primer *could, maybe, possibly* make a significant increase in the % of combustion that sends the bullet down the barrel.
 

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"I'll probably just buy a block of CCI Military Large Rifle and be done with it! I'm not getting close to "maxium loads" for now."

Mickey, primers matter, a little. Not so much for safety unless you develop a max hot load with a "mild" primer and then change to a "hot" one. But a primer change can blow your groups or improve them, and no one can predict which.

Your choice of a hot primer may disappoint you. Powders burn most consistantly within a certatin design range. Any peak pressure signifantly higher OR lower will burn erratically and a hot primer can be detrimental.

Seems many newbies assume a hot primer will be "best" but that's rarely true. They WILL make the ammo go BOOM but accuracy may suffer. Large cases crammed with slow or hard to ignite powders do frequently benefit from "magnum" primers. But, faster, easier to ignite powders in medium and small cases rarely do.

If I could have only one type primer it would be a mild one. Federal and Remingtons do well for me, especially so for small cartridges such as those you mention.

A chronograph is a nice tool but it may not be as helpful in determining peak pressure as you may think; velocity is NOT a direct function of chamber pressure. We can easily blow a gun apart with a too-fast powder while obtaining only modest or even low speeds.

Don't worry about your lack of "super human" vision for now, that will come with practice. Eventually you will be as able to count the grooves in flying bullets as the rest of us! ;)
 

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Wow I never would have thought there would be that much of a difference between them. I've been using cci primers looks like I need to switch to Remington:)


That's a really cool set of pictures.
 

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Beg, borrow, buy or steal a copy of "Any Shot You Want" from the "A-Square" company.
They did velocity AND pressure testing with different primer brands, powder lots, bullet brands, case brands, etc. The results are suprising, including some rather large pressure changes WITHOUT sugnificant changes in velocity.
 
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