Difference in primers

[Andrew Quigley]

Just curious what the difference is between magnum and standard primers. Is more pressure created or is it more velocity?

[felix]

That is not the way to look at it. It's the pressure curve itself. The shapes are different for each and every primer. The load is balanced only when the curves are almost equal when superimposed on each other. This can hardly be done at home without having many pressure measurements along the barrel per shot to obtain the shape of the curve. WHERE the peak pressure occurs is paramount to consistency and that takes precedence over the raw pressure amplitude at that point. Typically, magnum primers "burn" longer, not "hotter". ... felix

[Andrew Quigley]

Never heard that before. Thanks

[Larry Gibson]

Just curious what the difference is between magnum and standard primers. Is more pressure created or is it more velocity?

More pressure, generally. The hotter magnum primer causes a specific powder not to "burn hotter" per se but simply makes more of the powder burn at one time. The hotter longer flame temperature of the magnum primer is the reason. Thus with more powder burning at an earlier time in the time/pressure curve the peak pressure is higher.....generally.

The magnum primer itself creates a little more pressure but with medium to slow burning powders in rifle cases the increase from the primer is very small compared to the increase in pressure of the powder.

Larry Gibson

[Andrew Quigley]

In my 45/70 cases I use 5744 with good results except for unburnt powder that falls out into the action when I remove the cases from either my 74 Sharps or my Handi rifle. Use part of a cotton ball to eliminate part of this problem but I wonder if it would solve the problem by switching over to magnum primers.
Seems if it burns longer then more of the powder could ignite.

[RugerFan]

CCI advertises that their magnum primers have "23% hotter flame than standard primers" and "Increased flame duration."

http://www.cci-ammunition.com/produc...rod.aspx?id=29

[mpmarty]

Not to hijack this thread but I have found in my 308 using the 311413 bullet twenty grains of 2400 with LR primers won't shoot into a dinner plate at a hundred yards. Changing to LP primers my groups drop to around two inches and there are no abnormal flattening signs on the pistol primers. A kinder gentler ignition?

I never chronographed the L/Rifle loads but the L/Pistol rounds ran right at 1750 fps at 15' from the muzzle.

[35 Whelen]

Lately I've shot my 03A3 and my K-31 alot. By alot I mean probably 50-60 rounds per week. I use whatever primer will fit in the pocket, with the exception of large rifle magnum primers. In the K-31, I've used 8.0 grs. of Red Dot (this is my match load) and 6.0 - 7.0 grs. of Bullseye. In the 03A3, it's 15.0-16.0 grs of 2400. Honestly, I can't see 5¢ worth of difference in any of them. This is especially true in the K-31. It simply shoots really good groups with whichever primer I use. For what it's worth, I've used CCI200, WLR, WLP, WLP Magnum (LOTS of these because I don't have a magnum handgun in which to use them), Fed. 150 and CCI300. In the 03A3 I've primarily used the WLP Mag.
35W

[Andrew Quigley]

Went shooting my Handi rifle Saturday with some new loads I'd worked up for a 500gr lead bullet. Think after the five rounds in each string I had enough unburnt powder left over to half fill a 45/70 case! Well maybe not half full but a lot it seems.
Might have to try magnum primers with 5744 asI'm already using cotton balls to keep the powder closer to the primer for better ignition.

[Rocky Raab]

In general, I find that the mildest primer that provides reliable ignition will also produce the best accuracy. I firmly believe that this relates to the primer pressure prematurely unseating the bullet if the primer is too "hot". As the bullet never unseats the same way under primer impetus, accuracy goes to pot.

Also in general, unburnt powder is not the result of incomplete ignition, but a too-low operating pressure. Powder burns best in a certain "window" of pressures. With too small a charge, a given powder may well not burn completely (it actually goes out when pressure drops too low). Up the charge a wee bit and you often magically see the unburnt kernels disappear. Or change powders to one that is happier at lower pressures.

[Andrew Quigley]

Well I was trying out loads from the bottom of the scale to the top and got about the same amount of unburnt powder rom all. Course 4198 did about the same.

[monkeymt]

Glad I found this thread. I have been working with some new loads for my 45 Colt and tried Titegroup for the first time. With a Federal 150 I got lots of unburned powder all over the gun, in the cylinder, bore and on the frame. This is with 5.5 grains of Titegroup, 255 gr Keith SWC. When I switched to a CCI 300 primer with the same amount of powder I got almost no unburned powder. I have since loaded some with Unique and Clays both very clean with CCI's.
I was wondering if anyone else has had this experience with Federal primers.
Mark

[felix]

Mark, Federal primers typically output heat and very little, if any, flying sparks. Remington primers put out even more spark than CCI. So, use the proper primer for the ignition of the chosen powder column. Again, use the Federals with Unique and see if you get more accuracy than with CCI with your CHOSEN load. ... felix

[monkeymt]

felix,
Thanks, good information. Just loaded up some rounds with 6 grains of Unique, 255 gr SWC and Federal primers. You are right. This is an excellent load. Light recoil and very accurate. I shot ten rounds off hand at about 20-25 yards and kept them all in a nice round cluster of about 4 to 5 inches. No powder residue or unburned flakes anywhere very clean. I think that the new Unique is a bit cleaner than the old Hogdon but maybe it is just me.
Thanks again.
Mark