Larger ES and SD Using Magnum Primers?

[trackcage]

Let me start by saying I'm using H-110 powder in 44 magnum - a recipe which calls for the use of magnum primers.

When working up my testing loads, I loaded 5 of each powder charge using magnum and 5 using regular primers. The velocities were higher using magnum primers, some powder charges yielded a different variance than others. Surprisingly, in some cases, the velocities were damn near identical... making me wonder if it made sense to buy and stock magnum primers at all. However, for many of the 'sweet spot' loads where velocity, extreme spread, and standard deviation (SD) were the most consistent, the regular primers yielded a single digit SD while the magnum primers yielded a 12-17 SD (apologies, I don't have my chrono data in front of me, but can updated this with exact figures this evening). Same gun, same day, shot back to back, etc, etc.

Questions:

1. Has anyone else experienced this? Especially interested where a recipe specifically calls for a magnum primer.

2. Based on this experience, should I just go forward with standard primers versus magnum? It'd be one less component to stock and keep around, plus large magnum primers are sometimes more expensive, depending on where you look. I did unfortunately introduce one added variable. The magnum versus regular primers were of different brand, so I realize I'm asking to make a determination that is not exactly scientific.

P.S., this test ended with a good hand ache, as shooting 50+ full house 44 magnums in a row turned out to be about as much fun as it sounds

P.P.S, the load range and firearm used for reference. Standard disclaimer: test your own loads, I don't assume responsibility or make any safety claims:

S&W 29-10
6.5" barrel
H-110 powder charges 22.5gr - 23.5gr
240gr Keith style Hi-tek Acme bullet
CCI large magnum primers
S&B large regular primers
OAL 1.600"
Pretty good roll crimp but don't have that measurement handy at the moment.

[trackcage]

Edit to add a poll.

[bruce381]

go over to the cast boolits site look up 44 man.

He has a lot of 44 mag testing and says he uses the federal NON mag primers and they cut his group in half.

That mag primers opened the group he shoots at 100 yards I think.

good info over there, oh and he likes heavy boolits with that are hard cast.

[Divernhunter]

I use the mag primers when using H-110/Win 296. That is what all the books say to use. I also have gotten super good accuracy with my 357mag, 44mag and 454casull using the mag primers. I use to often shoot my pistols at 100 yards.

Do as you please but mag primers are called for and I use them. Actually I only buy mag primers and use them for all loads. I read an article in reloading mag where they showed better accuracy using mag primers in 357mag and 44mag loads using a number of different powders and also cutting the barrel shorter and testing.
I have been loading since the 1960's and years ago stopped buying reg primers. The results have been good with H-110(my favorite mag powder), Win296(same as H-110), Unique, Win231, 700-X, AL5 and 7, Blue Dot, Red Dot, Green Dot, IMR4227 and probably a couple others.

[trackcage]

I recall reading a few posts here suggesting to just keep it simple and but only magnum primers as posted above. I guess what had me confused is why H-110 calls for magnum primers and then is outperformed by regular primers.

[sghart]

In California I rarely use magnum primers. Why? Weather. If I were hunting in the UP of Michigan or in Minnesota at -50 degrees then I would use magnum primers to help ignite the powder charge.

Years ago I tried magnum primers for the same reasons you state. Nowadays I use standard primers.

There is a lot more to primers and you could spend hours on line reading up on it.

The highest SD's I have ever recorded were with magnum primers.

You will get hundreds of different opinions here. My advice is to buy a 100 count sleeve of standard primers from Bass Pro and then make up identical loads with magnum and standard loads. Then test them for your self. Then you will know and you can ignore 90% of the stuff you read on line. Including this post.


Steve in N CA

[Dark Hunt]

You use magnum primers to make certain that large loads of slow burning powder ignites and doesn't give you a hangfire.

Even if you're shooting IHMSA at 200 meters an SD of 15 is practically meaningless.

[Whiterabbit]

I voted std.

Buy a sleeve and shoot all 100 in a range outing. If you get 0 hang fires, good to go. If you get even one barely-hang fire, use magnums and deal with the SD, tho frankly 15 fps SD is meaningless for pistol

[sghart]

The SD figure may be meaningless for handguns, and I would tend to agree if we were all on the 15 yard line and shooting paper.

But high SD numbers can also be indicative of pressure spikes. If you load to the max or even slightly over, it may be of concern. Especially if the powder is temp sensitive. A hot day with spiky pressure loads and you could have a case separation.

Been there, done that.

[trackcage]

FWIW, The best performing load that I'll use going forward is 22.8gr or 23.0gr, so I'm at least a half grain off book max. These two charges performed well with either standard or mag primers.

[Whiterabbit]

Again, I recommend running a sleeve of std's first, not just load dev. It's easy to imagine a situation where you are on the edge. In that case, your load dev might work fine. Then when you have slightly less crimp, bullet on the small side, charge weight .1 down, primer not fully seated tightly, whatever variance you want to consider that is just natural in your loading (obviously no one has a variance of 0 in their loading!) you start to get hangfires.

I don't know. But it's a risk you should manage. 100 rounds should do it. If you don't get any hang fires in a 100 round range session with your chosen load, should be GTG.

IMO it's worth doing before you buy everything in super-bulk.

[Dark Hunt]

The SD figure may be meaningless for handguns, and I would tend to agree if we were all on the 15 yard line and shooting paper.

But high SD numbers can also be indicative of pressure spikes. If you load to the max or even slightly over, it may be of concern. Especially if the powder is temp sensitive. A hot day with spiky pressure loads and you could have a case separation.

Been there, done that.

You've had a case separation in a straight walled pistol case fired from a revolver?

[sghart]

I have an old S&W with two holes that are more generous than the other four. I had a max load of True Blue. The only primers I had were SP magnum primers. It was a June day at Spenceville, very hot. Was the case already weak and showing stress signs and I missed it? I don't know. Did I overcharge the case? I don't know. Did the 103 degree weather cause a spike? I don't know.

I believe it was combination of factors, but yes, I did. And I keep the remnants of the case on the shelf of my reloading bench as a reminder.

[Divernhunter]

If you are worried about an SD in the teens or even 20's I have many loads that shoot tiny groups with SD's in that range. I also have SD's with mag primers that are 2 and 3 and 6 or 7. Sometimes the higher SD load(10-29) shoot better.
Something else. I have loaded the same powder, bullet, primer, same length but in different brand brass at the same session and got SD of 2 on one, something higher on the next and 27 on the last one. Not always primers making the difference. They also had different speeds over my chrono and shot to a different place.

[jimmykan]

The S&B primers that I have shot so far (about 4-5,000 of various types including large pistol, but mostly large and small rifle) have yielded very consistent velocities.

They are definitely more consistent than US-made non-benchrest/match primers, and are about as consistent as Russian Wolf/Tula primers, i.e. as good or better than US-made benchrest primers.

As long as I were not experiencing any ignition probems with the non-magnum S&B primers, even in cold weather, then I would keep using them.