Any advantage to using magnum primers over large pistol?

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grobin

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For a medium-large pistol cartridge like 10mm is there an advantage to developing loads with magnum primers over large pistol when using slow powders?
 

mikld

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If magnum primers are the only primers available, then mebbe yes, that can be an advantage. Magnum primers are not just for Magnum cartridges/guns, they are for more difficult to ignite usually slower burning powders.
 

dougader

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I'd use the primers listed in the loading data I was using for my loads.

Any change to magnum primers should be countered with a lower starting charge, especially if you're already using an upper end load.
 

Chief 101

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for me with thousands of CCI 350 and maybe a thousand CCI 300 I find uses for magnum primers in lots of lighter loads...in some cases better accuracy...in some cases no dif...even with lead 30-30 Win cast loads I get great results. There is no need to live on the edge when reloading so at least experiment with less than max loads first and see what your results are, make your own decision based on positive results. Have fun and be safe.
 

mikld

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For experienced reloaders this is a moot question, but for a new reloader without understanding of how primers affect the performance/pressures of a cartridge, it's best to stay with what your reloading manuals suggest. K.I.S.S....
 

Rclark

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Remember magnum primer doesn't mean for magnum guns. Which primer you use is 'usually' (most of the time) is dictated by what powder you use. For example, H110/W296 you should always use a magnum primer. Same with 4227. As said above, sometimes, you find the magnum primer works better with a load than a standard and visa-versa. I've seen some loads where using a magnum primer increases the Extreme Spread in back to back tests. Spot checking one of those back to back tests I see where ES 44fps (standard) and ES 88fps (Magnum). Some other powders exactly the opposite results, other times makes no difference at all. Why we test what works in our guns! Note that in small volume cases I would use the recommended primer and load first (in the manual) as it doesn't take much to increase the pressure beyond SAAMI.
 

Divernhunter

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I have gone to using mag primers in all loads. I have had no problems even with max loads and the accuracy is usually better. Been doing so now for many years on everything from 9mm/45acp/38special/357mag/44mag(also light loads)/ 454Casull(small rifle mag primers)/500S&W as well as some odd mil cartridges. All rifle cartridges get mag primers also.
 

jgt

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Anyone who uses a one size fits all concept to reloading is on a pathway to loosing body parts. If a person will not put the effort into learning to reload, they would be well served to buy their ammunition from a reliable factory. It may not be the best, but it will more likely be a lot safer.
 

mikld

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If an experienced reloader works up a load, from starting loads and up, when using Magnum primers, there is probably no danger. If one haphazardly slaps some Magnum primers in their cases and uses "Bubba's" load data which is "only" .2 over max., then yep, expect trouble, like rapid disassembly of your gun...

Reloading manuals aren't hard and fast formula, but they tell us what a test technician found and is safe....
 

Rick Courtright

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mikld said:
Reloading manuals aren't hard and fast formula, but they tell us what a test technician found and is safe....

Hi,

True to a point! Problem is, they don't tell where that technician found things started to go sideways, or how badly they did when that happened.

My uncle worked for a company which makes solid rocket fuel: smokeless powder on steroids, for lack of a better description. It turns out, though he was neither a gun owner nor a handloader for himself, he did a lot of handloading in the the lab, as they used shotshells in setting up their initial models for the computer on what was going to happen. They were pretty good at it, too.

Until one day, when they'd been "working up" a load much as we do at our loading benches, except they had a bazillion dollars worth of test equipment we don't. The load had been progressing in a fairly linear fashion. So their predictions were that the next increment should produce x number of PSI in the predictable fashion it had been. They loaded it up, and my uncle took it into the test firing chamber (he said it looked kinda like a blasting cabinet, except for being supposedly explosion resistant) and set up to fire the first round.

KABOOM! It was one of those situations where the last load was just under the safe limit, and it took almost nothing above to simply fly off the chart, regardless of what the computer had predicted. Uncle was injured as the test chamber came apart, and it was touch and go whether he'd lose his sight (fortunately, he ended up ok.) Point being, the lab techs who write our loading manuals deal with this kind of stuff all day, and are prepared for "bad results." We're not. So it doesn't bother me a bit to take those guys' word for what works and honor their limits, not does it bother me to tell Bubba he ain't got a clue when he says "Just a pinch more oughta be fine!"

I know, I know: there are a lot of people who subscribe to the "It ain't blow'd up yet, so it must be safe" school of thought. After damaging a gun beyond repair through such ignorance myself when I first got started 50+ yrs ago (one of the dangers of being self taught with no mentor or overseer), and seeing my whole display case full of bits and pieces gathered from people who did the same at our range, I'm just not one of them.

Rick C
 

Bob Wright

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I have found that Winchester WLP primers work very well with all loads across the board. For some reason I believe they are less temperature sensitive than their magnum counterpart.

In very cold weather, freezing or below, I have had failure to ignite the powder charge with heavy loads of 296 in the .45 Colt.

Bob Wright
 

DGW1949

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Rick Courtright said:
mikld said:
Reloading manuals aren't hard and fast formula, but they tell us what a test technician found and is safe....

Hi,

True to a point! Problem is, they don't tell where that technician found things started to go sideways, or how badly they did when that happened.

My uncle worked for a company which makes solid rocket fuel: smokeless powder on steroids, for lack of a better description. It turns out, though he was neither a gun owner nor a handloader for himself, he did a lot of handloading in the the lab, as they used shotshells in setting up their initial models for the computer on what was going to happen. They were pretty good at it, too.

Until one day, when they'd been "working up" a load much as we do at our loading benches, except they had a bazillion dollars worth of test equipment we don't. The load had been progressing in a fairly linear fashion. So their predictions were that the next increment should produce x number of PSI in the predictable fashion it had been. They loaded it up, and my uncle took it into the test firing chamber (he said it looked kinda like a blasting cabinet, except for being supposedly explosion resistant) and set up to fire the first round.

KABOOM! It was one of those situations where the last load was just under the safe limit, and it took almost nothing above to simply fly off the chart, regardless of what the computer had predicted. Uncle was injured as the test chamber came apart, and it was touch and go whether he'd lose his sight (fortunately, he ended up ok.) Point being, the lab techs who write our loading manuals deal with this kind of stuff all day, and are prepared for "bad results." We're not. So it doesn't bother me a bit to take those guys' word for what works and honor their limits, not does it bother me to tell Bubba he ain't got a clue when he says "Just a pinch more oughta be fine!"

I know, I know: there are a lot of people who subscribe to the "It ain't blow'd up yet, so it must be safe" school of thought. After damaging a gun beyond repair through such ignorance myself when I first got started 50+ yrs ago (one of the dangers of being self taught with no mentor or overseer), and seeing my whole display case full of bits and pieces gathered from people who did the same at our range, I'm just not one of them.

Rick C

I'm hearin' ya Rick.

DGW
 

mikld

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True to a point! Problem is, they don't tell where that technician found things started to go sideways, or how badly they did when that happened.
The point at which the load becomes questionable, or approaching dangerous pressures are listed under "Maximum loads" or "Do not exceed"...
 

SAJohn

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Just to carry on with Rick's post about sudden pressure rises with propellants:

First are my bona fides, at a Navy R&D center I headed the solid rocket propulsion branch for a number years. We used special pressure chambers to measure burn rate versus pressure for new propellant formulations. There would always be a certain point where a small increase in pressure would cause a large increase in burn rate followed by a big bang. You do not want a big bang!
 

Rick Courtright

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altajava said:
book data is a guide, it's not written in stone. Otherwise we'd all be shooting guns with the exact same barrels on them

Hi,

This is true. However, until you or I have the testing equipment necessary to find out if our own home brewed recipe is TRULY safe, it's the best thing we've got. And whoever thinks they can out eyeball that equipment, well, I hope nobody gets hurt as you revel in your ignorance. "It ain't blow'd up yet, so it must be safe" doesn't do much for some of us...

Rick C
 

grobin

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Mar 8, 2016
Messages
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Rick Courtright said:
altajava said:
book data is a guide, it's not written in stone. Otherwise we'd all be shooting guns with the exact same barrels on them

Hi,

This is true. However, until you or I have the testing equipment necessary to find out if our own home brewed recipe is TRULY safe, it's the best thing we've got. And whoever thinks they can out eyeball that equipment, well, I hope nobody gets hurt as you revel in your ignorance. "It ain't blow'd up yet, so it must be safe" doesn't do much for some of us...

Rick C

I must disagree! There are plenty of indications of load problems that simply require basic knowledge of over pressure signs, and don't require a pressure barrel. A good chronograph helps as well. Further a pressure barrel isn't that expensive for a single length and caliber.

You must use good judgement and care. Approach published data as possibly useful guidelines not gossipal!
 

Chief 101

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Rick Courtright said:
altajava said:
book data is a guide, it's not written in stone. Otherwise we'd all be shooting guns with the exact same barrels on them

Hi,

This is true. However, until you or I have the testing equipment necessary to find out if our own home brewed recipe is TRULY safe, it's the best thing we've got. And whoever thinks they can out eyeball that equipment, well, I hope nobody gets hurt as you revel in your ignorance. "It ain't blow'd up yet, so it must be safe" doesn't do much for some of us...

Rick C
I totally agree with Rick on this subject
 
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