Magnum Primers?

[Pictures]

I bought some Mag CCI primers on accident. Do I need to decrease my powder charge in order to use these?

 

[T Bran]

Unfortunately yes drop down and work back up.
Anytime you change a component drop back, the only exception is if you are already at or very near the starting charge weight.
T

 

[Pictures]

I'm at the limit.

Ok, will do. Thanks!

 

[MovedWest]

In my loading world I usually drop 5% off the powder charge to accommodate the extra fire of a magnum primer. But that's what I've worked out with my load data.

Since you're at the max, I'd err on the side of caution and work it back up. Keep good notes in case it happens again or there happens to be another run on components where regular primers are in short supply. Versatility is good.

-MW

 

[MachIVshooter]

Generally speaking, magnum primers will increase chamber pressure by igniting the charge faster. As stated, you should drop it back a bit. Don't really need to work up from minimum, but I'd go right in the middle between min and max.

 

[jcwit]

Just asking, why are you loading at the max limit?

 

[ArchAngelCD]

Just asking, why are you loading at the max limit?

That was going to be my question too.

What caliber, bullet, powder and charge weight are you loading?

 

[TonyT]

I made a similar mistake when I was loading some very light 40 S&W loads (180 gr. bullets at ca 725-750 fps) and did not recognize that the box of primers I purchased were magnum instead of normal. When I chronohraphed those loads they were ca 10-20 fps faster than those with normal primers. I would not use them if the cartridges I loaded were at the upper end or max of the powder manufacturers data.

 

[joed]

Just asking, why are you loading at the max limit?

I have to ask why not? The world does not end at the max shown in a loading manual. It's a reference point and it's not set in stone. I've had many instances using Varget where I needed to increase the charge by 1.5 gr to get the velocity advertised. So far this is the only powder that has done that to me.

 

[kingmt]

I agree you can go beyond max in most books with most guns. I tend to be +/- 1gr of min for most of my rifle loads & just barley over min with most pistols. Except for one of my SD loads & that is because I need to push them pretty hard to get them to open. I could switch to a slower. Powder but they shoot so good & recoil is smooth. I'm about 1.2gr over with that load.

I don't see a difference with mags but it is possible that you could get better ignition so doesn't hurt to be safe.

 

[Jasper1573]

I have loaded up to the max in .308 Win using Lyman's data for SMK 175s and the Hornady AMax 178s. I found a slight increase in velocity, a slight decrease in accuracy, and a significant increase in perceived recoil.

Didn't see the point in loading at or above the max just to receive an extra beating at the expense of accuracy...then again, I am not shooting an elk. If I were, I might load up to the max load, but white tails are easy to bring down.

 

[Pictures]

That was going to be my question too.

What caliber, bullet, powder and charge weight are you loading?

Why am I loading at max?

Should I not be doing this? I mean, they work, the rounds have a sufficient feel to them so that's what I've been going with. I'll admit I don't know anything about ballistics or velocities or any of the science behind it, I simply know that they work, but I'd be interested in hearing arguments against doing so.

My load info, as requested:

Brass: once fired mixed head stamp
Bullets: Berry's .45 acp 230gr round nose FMJ
Powder: 5.6 gr (+/- .2gr thanks to my lee auto powder measure) of Clay's Universal
CCI Primers

 

[Lost Sheep]

Juvenile and not THR.

Loading to maximum is a choice. Most people find their gun's "sweet spot" for accuracy somewhere between minimum and maximum. Kingmt (post #10) has found his bullets' terminal performance "sweet spot" above max, but presumably has searched for pressure signs and found none, so for his gun, that is OK.

I imagine that if a ballistics lab worked up loads using Kingmt's gun, the max load would be at his load or maybe even higher. Each gun is unique and its own max load might be above or even below the "book" max. That is why we start low and work up.

Anyhow, the boldfaced part is the argument against loading at max. There is another argument (for those who have more than one gun in the same chambering) to be made for not using any load at or even near max that has not had that load worked up in that individual gun.

Lost Sheep

 

[Pictures]

If I remember correctly, I started loading at the minimum and when I shot it, it felt really weak compared to the factory ammo I had shot, so I went ahead and maxed it and it seemed about the same power as the factory ammo.

I also used this site as a reference. It seemed like a lot of people, using the same powder and similar bullets, were using much higher gains that I were and they said it worked fine, so I figured I was safe at 5.6. I never even tried to find this "sweet spot" you speak of. Maybe I should go back and do that?

http://forums.1911forum.com/showthread.php?t=255286

 

[joed]

Why am I loading at max?

Should I not be doing this? I mean, they work, the rounds have a sufficient feel to them so that's what I've been going with. I'll admit I don't know anything about ballistics or velocities or any of the science behind it, I simply know that they work, but I'd be interested in hearing arguments against doing so.

Nothing wrong with loading to max, and remember that it is not written in stone that the max is really the max safe load. You may find an instance where you can't shoot a max load from a manual without pressure signs, and you may have an instance like I mentioned where you have to go beyond max. The trick is you work up to that load. It's nice to have a chronograph for this reason and read the cases.

 

[Ky Larry]

The reason I load for accuracy and not velocity is that a hit with a .22 short is better than a miss with a 20mm cannon. Who cares how fast a round is if it's not accurate?

 

[jcwit]

I load for accuracy, and usually thats far below max. I get more loads per pound of powder, my brass lasts longer, usually as much as 100 reloads per case in .223. And guess what? The paper target dies just as quickly and without suffering. But as always YMMV.

 

[Pictures]

I want to load for accuracy too, so maybe I should start from scratch?

Btw, keep in mind that I'm loading to the max according to one manual. Apparently others put the max for my components at 6.0 grains, so on that scale, I'm not at max.

I think what i'll do is make 20 rounds per varying load, try them out, see what groups the best then go with that.

 

[joed]

I load for accuracy, and usually thats far below max. I get more loads per pound of powder, my brass lasts longer, usually as much as 100 reloads per case in .223. And guess what? The paper target dies just as quickly and without suffering. But as always YMMV.

You're a minority, every rifle cartridge I own gives its best accuracy very close to the max loading. It suspect it has a lot to do with air space in the case though I can't vouch for that.

That's rifles, pistols are different. There are a lot of things that effect the accuracy of a pistol.

 

[Lost Sheep]

If I remember correctly, I started loading at the minimum and when I shot it, it felt really weak compared to the factory ammo I had shot, so I went ahead and maxed it and it seemed about the same power as the factory ammo.

I also used this site as a reference. It seemed like a lot of people, using the same powder and similar bullets, were using much higher gains that I were and they said it worked fine, so I figured I was safe at 5.6. I never even tried to find this "sweet spot" you speak of. Maybe I should go back and do that?

http://forums.1911forum.com/showthread.php?t=255286

The "sweet spot" thing is more applicable to rifles than to handguns. Supreme accuracy is more apparent ar rifle distances than at handgun distances. Which are you loading for? (When I posted my earlier answer you had not provided the clue of the 1911forum link.)

Finding the sweet spot for a rifle involves some experimentation and sorting out barrel harmonics (also known as "barrel whip") other esoterica that is, frankly, beyond me. But truly worth it when you find a load that turns your 2" 100 yard groups into half-inch groups.

I forgot one point about why people often shy away from the maximum load. Powders burn at a rate that depends on the pressure. Outside that range, they (may) burn erratically. In most firearms and for most powders, the optimal, most uniformly burning pressure will be found between the high and low extremes. Consult the science of "Internal Ballistics" for more detail.

For that reason, many (not all, by any means, but at least some), if they find the bullet velocity that is most accurate in their barrel and discover that it is at the high end of the powder charge range, will switch to a powder that delivers that velocity closer to the middle of the charge range and search for the sweet spot with that charge weight.

For handguns, the reasoning is probably more for safety, and this applies to rifles as well. A slight overcharge (it happens) if you are already at pressures approaching the limits of safety is more dangerous than a slight overcharge if you are in the middle pressures.

In closing, the search for the perfect load is like tuning anything. Arranging the perfectly composed photograph or flower arrangement. Tuning dual SU carburetors so finely that you can balance a nickle on a 4-cylinder engine idling at 300 rpm. I was not able to do that last one, by the way, but the search for it was reward enough. If you can understand the quest for the impossible, you owe it to yourself to try doing it, if not with your firearms, with something.

Lost Sheep

 

[kingmt]

Like I said in a post above, I get my best accuracy +/- 1gn of min.

As far as the load worked. Yes. My pistol is a tank & the slide is very havey. There is no +P data for this powder but I doubt it is over that. It is also my SD round so it isn't likly any more will be shot through it.

I normally load where it just does function the slide. No need to beat up my guns for no reason.

You can't check pressure by felt recoil. I also wouldn't strive for factory loads. I shot one the other week 9mm 187 fps.

 

[Lost Sheep]

You're a minority, every rifle cartridge I own gives its best accuracy very close to the max loading. It suspect it has a lot to do with air space in the case though I can't vouch for that.

That's rifles, pistols are different. There are a lot of things that effect the accuracy of a pistol.

Joed, I know that you know that filling the case (or even having a compressed load) is NOT the same as the maximum load, but some readers could misinterpret your post.

And, yes, having empty (air) space in a case can make a HUGE difference, in velocity at least. I have observed this first hand myself simply because of powder position within the case. Some shooters deliberately pick powders that not only are mid-pressure range, but case-filling as well just for that reason. Others simply fill the empty space in the case with an inert filler.

Muzzle loader shooters are, of course, not concerned with air space because with their loads there never is any.

Lost Sheep

 

[Pictures]

Lost sheep, it's .45acp for pistol.

 

[coalman]

You should drop down and work back up. I never do and it's not mattered.

 

[ArchAngelCD]

Actually, when I agreed with the question, "Just asking, why are you loading at the max limit?" I read it too fast and thought the question was, "Just asking, what are you loading at the max limit?" That's why my next question was, "What caliber, bullet, powder and charge weight are you loading?"