Standard primers vs. Magnum primers

[Newtosavage]

For the first time last week, I worked up a couple loads that were identical but for the primers. One load used standard CCI 200 large rifle primers and the other used CCI 250 Magnum rifle primers, behind 57 grains of RL-19 in my .280.

The magnum primers gave me a slightly smaller group, and nearly 80 fps. more velocity.

Is that normal? Would a load that is safe with a regular primer potentially be over pressure with a magnum primer?

 

[Laphroaig]

That's interesting. If there are no pressure signs with that load then the magnum primers have a positive impact.

But you never indicated what bullet you are using. 57 grs. of RL-19 is a near max load for both 120 and 140 grs. according to Nosler, so be careful.

I've used magnum primers for both 280 and 25-06 before, and never saw that large of a difference.

 

[Newtosavage]

I was shooting 154-grain Interlocks. I know it's a couple grains over max but I also know that most of the .280 load data is dumbed down for the autoloader rifles originally chambered for it.

I should have mentioned the POI for those two groups was about 3/4" apart too.

I check my brass closely, measure for case head expansion and primer pocket expansion and those loads - while hot - seem fine in my rifle. So far I've noticed that for my gun, the faster I push a bullet the tighter groups I get. My shoulder isn't happy about that though. But it is what it is.

 

[cougar1717]

Is that normal? Would a load that is safe with a regular primer potentially be over pressure with a magnum primer?

Yes, it's normal. The large charge of ball powder is burning more completely and consistently with the hotter primer. More ignition, more efficient transfer from solid to gas, less unburned powder, more velocity (up to a point). With a load worked up for standard primers, adding a magnum primer may potentially be over pressure. You don't know without working up the load with mag primers. That is why reloading manuals stress working up a load if anything changes. Checking for pressure signs is also imperative since a workup is usually for an individual rifle. That's why it's difficult on a forum to affirm if a given load is ok, especially near max charges. In one person's rifle, it is just fine. In another, the primers are flat as a pancake. It sounds like you have access to a chrono since you know it's 80fps difference. That is a great tool in trying to check your load combinations.

 

[Bart B.]

Some standard primers are hotter than some magnum primers. Cooler/milder primers may enable better accuracy than hotter/stronger ones. A friend rigged up a 17 caliber barrel to shoot BB's from a 17 Rem case. Milder primers shot BB's slower but more uniform in muzzle velocity. They also shot bullets from normal cases more accurate than hotter ones.

Best way to see which one puts out more fire is to shoot both in primed cases in as short of barrel as possible; in a dark room where you can see the flash.

http://www.6mmbr.com/PrimerPix.html

 

[Newtosavage]

Yes, I have a chrono and I can't imagine reloading without one.

Thanks for the input. At least for RL-19 I think I'll be using magnum primers from now on.

 

[Reloadron]

The large charge of ball powder is burning more completely and consistently with the hotter primer.

Isn't RL 19 an extruded rather than ball or spirical type powder? I was thinking that RL powders 7, 10, 15, 19, 22 and 25 are all extruded stick type powders.

Anyway, what you saw is normal. If the magnum primers give you slightly more velocity for a given load and there are no bad pressure signs then run with the magnum primers. I have done this with extruded powders in .223 Remington as well as .308 Winchester. While in the .223 I don't always get the higher velocities surprisingly in my bolt gun.

Ron

 

[Bart B.]

Yes, I have a chrono and I can't imagine reloading without one.

I don't care what the velocity is my reloads shoot bullets. I know their speed is probably within 150 fps of recipie claims. Try to imagine those hundreds (thousands?) of reloaders who don't have a chronograph. Me, for example.

 

[Newtosavage]

Oh, I do. And I don't understand why $100 would keep you from knowing your trajectories. But maybe that's just me. I want to know, for hunting. I take that number and work it through the ballistics calculators so I can figure out my reticle drops for a particular load. Thankfully, most scope mfg's are publishing reticle subtension data these days.

I also know if I keep adding powder and don't see much change, or if all the sudden I see a spike, I know something is up.

 

[Reloadron]

I view the chronograph as a "nice to have". I have one because about 25 years ago my wife gave me an Oehler 35P for Christmas. I really don't much care how fast my bullets are traveling, it's a nice to know. What I care about is when a group of five or ten of my bullets are a few hundred yards down range how close they are to one another. Really, all I care about is my group size. I can look at spent cartridges and tell if I am pushing any pressure limits. I was rolling my own long before I received a chronograph as a nice gift. It wasn't a necessity then to make good ammunition and it isn't a necessity today.

Anyway, here nor there. The results you are seeing are normal and would be expected. I would remain focused on group size and not velocity. Long as you aren't seeing any pressure signs, life is good.

Ron

 

[Bart B.]

I don't understand why $100 would keep you from knowing your trajectories.

Because after I get zero's at a few range points, I bracket and halve velocities in software set to range conditions. The metallic sight adjustments I use are a dozen times more precise than scopes so when a velocity calculates data shot, it's a match to reality. Then I can calculate sight dope for a wide range of target distance and atmospheric conditions.

 

[Newtosavage]

I bet my chrono costs less than your sights. LOL

I hear what you're saying though and I know there are other ways, and ultimately it's about where they land. But I want to know ballistics and energy downrange to feel confident with my load at a given distance.

I just don't see how less information is a good thing. So I use what I have.

 

[Bart B.]

I bet my chrono costs less than your sights. LOL

It probably does.

All I care about is bullet drop and wind drift down range. Software calculates that.

 

[.308 Norma]

Isn't RL 19 an extruded rather than ball or spirical type powder? I was thinking that RL powders 7, 10, 15, 19, 22 and 25 are all extruded stick type powders.

Well, RL 22 is an extruded, rather than spiracle ball powder for sure. It's my favorite powder for my beloved .308 Norma and my wife's 7mm Rem Mag.
We worked up the loads with CCI Large Magnum primers to start with though.

 

[ArchAngelCD]

I must admit about 10 years ago I thought I just have go have a chronograph so I bought one. The first year I sent everything over those sensors. I also must admit it's been many years now since I even looked at it let alone used it. I am very happy I never left batteries in the thing lol.

I used to think the SD numbers had to be low for the accuracy to be good. Now days if the ammo is accurate, it's good...

 

[Newtosavage]

Agreed on the SD #'s and accuracy. Some of my best SD loads are not all that accurate, and some of my most accurate loads have pitiful SD's.

I just want the data for ballistics. Once I've settled on a load, I don't use it after that if I'm shooting that load.

When I'm working up loads, I do want to see a consistent jump. When it changes, that's when I pay real close attention.

 

[ArchAngelCD]

Every one has a set way they like to use to get to the end. As long as it's safe and it works it a good way to do it. There are usually more than one,way to achieve a goal.

 

[Sunray]

"...can't imagine reloading without one..." 40 plus years of reloading with no fuss. A chronograph is one of the many current 'must have' tool fads you can do without. Accuracy is far more important than velocity. And knowing the approximate velocity doesn't help or make much difference.
What you get by using magnum primers with powders that don't need 'em is slightly higher pressures. Operative word being 'slightly'. As in not enough to hurt anything. And mostly that you might have slightly higher pressures. Using magnum primers is a normal thing in extreme cold weather.
"...to shoot BB's..." As in solid copper .177", 8.2 grain, BB's, out of a 1.796" case? I wonder if a different cartridge would change anything.

 

[Bart B.]

17 Rem chamber necks are within SAAMI specs from .200" to .202" diameter. A BB gun barrel, 17 caliber, was fitted to a rifle barrel chamber section.

Please solve this problem:
----------------
.177" diameter BB's will work well when case neck wall is no more than " thick.

a. .017"
b. .016"
c. .015"
d. .014"
e. .013"
f. .012"
g. .011"
h. .010"
-----------------
A different cartridge may work if it's the same size case capacity.

I've shot 7.62 NATO primed cases with 190 grain bullets but no powder in the case. Bullets stayed in place. Everything inside the case was coated with grey-black primer residue.

 

[jmr40]

Reloading without a chronograph is like driving without a speedometer. Unless you drive like grandma sooner or later you'll get into trouble either way. I don't need an expensive chronograph, just want one to let me know if I'm approaching a hot load and to know when to back off before developing a dangerous load. I'm not one to push the envelope past published loads, but I don't want my hand loads to be 100-150 fps slower than what I can get from a box off the shelf either. Which is exactly where most mid-level loads in most loading manuals are.

With certain combinations of rifles, bullets, powders and primers I've found loads well under published max, near the middle, that were getting too warm for my comfort zone. There were no pressure signs, YET, but traditional pressure signs don't show up until you are well past the danger zone. Without a chronograph I'd have never know those loads were too hot and may well have gone up even more on the powder charge instead of dropping down. Or simply giving up on that combo, which is what I've done. I've found it better to just try a different powder when that happens.

One observation I've made with some powders is that you may be 2 or more gr below max and have mediocre velocity. Move up .5 grain and still be well below published max, but suddenly you get pressure signs and the velocity is 100 fps faster than it should be at a max charge. Other powders seem to be more predictable. Another good reason to have a chronograph. At $100 or so I can't see not using one. It's cheap insurance.

Knowing the exact velocity I'm getting will help calculate approximate bullet drop, but I'd not trust those numbers until I actually shoot at the ranges. But that is really secondary for me.

As to getting a little more speed with magnum primers that sometimes happens, sometimes not. It just depends on the exact load. If you want to use them it won't hurt a thing as long as the extra speed doesn't push you into a over pressure load. Most people end up reducing powder charges a bit when going to hotter primers.

 

[Newtosavage]

Actually, using my chrono readings and published BC's have gotten me really, really close to real world ballistics to 300 yards at my range. Usually within an inch at that distance, which is why I like having that data.

Again, for $100 I can't see why a person wouldn't want the data. For example, I would have never known that the magnum primers alone were pushing my load 80 fps. faster. I want to know that.

 

[someguy2800]

I've had some magnum primers make a load shoot 150 fps faster. I've seen some loads shoot slower with a magnum primer from brand A than a standard primer from brand B. It been my general experience that most stick powders doesn't make much difference.

A chronograph is a box that gives you info that may or may not be accurate, and may or may not be useful. In the case of mine if you don't have it perfectly in line side to side and up and down it will give you different readings. If the sun is low in the sky it will give you different readings. If the sun is 11 oclock instead of 8 of clock it will give you different readings. There are a couple loads that I've ran through the chrono that tipped me off that I was either way cold or way hot on a certain load despite what the load book says so its can be nice for that. I don't use it to tell me if my load is safe or not. I let the brass and primers tell me when they are happy. In some ways I wish I would have never bought a chrono. I've had a couple sweet loads that I was perfectly happy with until I found out the velocity. Sometimes my brain has a fight with itself over the load that shot best and the next higher load that still shot okay but gave me 60 fps more velocity.

 

[.308 Norma]

In some ways I wish I would have never bought a chrono. I've had a couple sweet loads that I was perfectly happy with until I found out the velocity. Sometimes my brain has a fight with itself over the load that shot best and the next higher load that still shot okay but gave me 60 fps more velocity.

Ha! I think a lot of guys (me included) have problems like that. It must have something to do with being male.

 

[Reloadron]

I've had some magnum primers make a load shoot 150 fps faster. I've seen some loads shoot slower with a magnum primer from brand A than a standard primer from brand B. It been my general experience that most stick powders doesn't make much difference.

Yeah, having played this game before with magnum and standard primers in both .308 Winchester and .223 Remington. Not sure where the .308 Winchester dope is but I have the .223 Remington dope. These were ten shot groups using four different primers with identical loads and bullets. The primers used were all CCI and were CCI 400 Small Rifle, CCI 450 Small Rifle Magnum, CCI BR4 Small Rifle and CCI #41 with the CCI 450 and #41 being magnum primers while the CCI 400 and BR4 are standard primers.
Brass: LC 11
Powder: H335
Bullet: Sierra 53gr HP Match

The target was more an afterthought as I was more concerned with getting the rounds through the chronograph. They were all ten shot groups with ten shots used to compile the data for each primer. So the magnum primers did not necessarily always turn in the fastest velocities. Using the H335 the magnum primers did print slightly better but again I was not focused on groups so I can't say they were better with any certainty.

Ron

 

[Orcon]

Reloading without a chronograph is like driving without a speedometer.

No it's not. If you want to tease velocity to the max for any given load you need to use a strain gauge and the appropriate software to parse the information.

A chronograph is at best a crutch, at worst an unreliable one.

Of the folks I know who rely heavily on their chrono, most can't get off of the 100 yard lane.