Large Pistol Magnum Primer Question

[Art in Colorado]

I have 100 cases of 41 Mag primed with CCI Large Pistol Magnum Primers. I normaly load 41 Mag with a 210 Gr Cast and 8 Grains of Unique and a standard primer. I have no use for the magnum primed cases. Would you use my normal loading with these cases or would you reduce the amount of Unique Powder? Do not want to de-prime these cases if I don't have to.ThanksArt

[Larry Gibson]

That is a relatively mild load of Unique under the 210 cast bullet. Using the magnum primers will not present a problem with pressure. You might load up a dozen and try them for accuracy. If they shoot as well as with standard primers then I'd load 'em up and enjoy.

Larry Gibson

[Dale53]

As usual, Larry gives good advice.

Dale53

[Art in Colorado]

Thanks for the advice.Art

[44man]

Only accuracy might suffer. Higher pressure primers can start the boolit out soon.
Not too bad with Unique as it will light off. It should be OK.
But it is the "BOOK" thing since the case head says "MAG." Even with H110/296, I would not use a mag primer. I have not used a mag primer in the .44 for 38 years and the .41 is smaller. All I shoot is 296.

[Lloyd Smale]

Yes it can effect accuracy. But it can effect it to the good as well as to the bad. Ive seen loads with powders like unique, herco, and universal clays actually shoot better with mag primers in a certain gun. So it sure cant be wrote in stone. Ive tried LOTS of mag pistol ammo with 110/296 and again primer selection isn't wrote in stone but ive seen more of them shooting better with mag primers then standard and have seem much better velocity swings over my chronograph with 110/296 and aa9 using mag primers. Unless your shooting absolutely top end pressures and try to down load even a little the swings can run as high as 200 fps. That might not show up at 25 yards but it sure will down range. That and Ill add that a lot of my handgun hunting is in cold weather where the cold can weaken primers and make those swings even worse. So much so that in real cold weather ive had slightly downloaded aa9 loads with standard primers that even sounded odd when shot. Anymore I see no use in using std primers with these rounds. they cost no less and if I just start with something like a cci350 and tweaks powder charges bullet alloys, lubes, bullet size ect I will 99 times out of a 100 find a great load and a load I can trust even if its below zero. Bottom line is primer selection is just one small variable in finding an accurate load. I know weve gone round and round over this topic but personaly I cant see using standard primers just to prove it can be done. Just for an example during the primer shortage I loaded cci small rifle primers in 9mms because I had nothing else. I found a load with aa2 in my full sized M&P that shoots hands down better then any load ive tried before in it and still use that load in that gun with a good supply of small pistol primers sitting on the shelf.

Only accuracy might suffer. Higher pressure primers can start the boolit out soon.
Not too bad with Unique as it will light off. It should be OK.
But it is the "BOOK" thing since the case head says "MAG." Even with H110/296, I would not use a mag primer. I have not used a mag primer in the .44 for 38 years and the .41 is smaller. All I shoot is 296.

[Hickory]

Lloyd hit the nail on the head, slower powders will burn better with magnum primers.
I use magnum primers when the temperature is 15° or less when hunting.

[44man]

I made tests to -20° in Ohio with 296 and both primers. Groups did suffer but the fed 150 still shot best.
Primers should be tested back to back and case size is important. The .41 is real small.
The primer can supply more velocity to poor loads and show better results. You substitute primer pressure for the powder charge. My .44's will never see a mag primer and the .41-NEVER.
Friend shot his .500 X frame yesterday. Loaded with LR primers. WHY? Waiting for the next test with LP mag primers. The case was cut for LP but some jerks used LR and got slam fires so brass was changed. Not an ignition problem just stupid.

[Soundguy]

Best advice is to stick to standard reloading practices. If you change a component, as a test, start back to minimum load, and load up looking for pressure issues.

if no issues.. no issues.

[44man]

Books call for a mag primer with every case stamped "mag."

[Plate plinker]

I have 100 cases of 41 Mag primed with CCI Large Pistol Magnum Primers. I normaly load 41 Mag with a 210 Gr Cast and 8 Grains of Unique and a standard primer. I have no use for the magnum primed cases. Would you use my normal loading with these cases or would you reduce the amount of Unique Powder? Do not want to de-prime these cases if I don't have to.ThanksArt

Dang what a problem.
Solution load them up and use them for practice and then load them however you like after that. No big deal. Have fun.

[44man]

Dang what a problem.
Solution load them up and use them for practice and then load them however you like after that. No big deal. Have fun.

I agree but record results.

[Mytmousemalibu]

I have seen accuracy go both ways with or without a magnum primer. There's lots of variables that effect the outcome. The powder type has a large portion of the variable but not limited to things like bullet type, bullet weight, crimp, temperature, flash holes, etc. You have to experiment to fine tune your loads. My 9mm 124gr Major power factor load of 6.8gr of Silhouette did very well with a standard primer, the load shot consistently a single digit standard deviation over the chrono. My new 115gr load of 9gr of 3N38 likes a magnum primer better.

[Boogieman]

I just crono'ed some 41mag. loads 215gr. swc over a large charge of 2400. Used CCI350 & WWLP primers. In THIS test the WWLP loads were faster, about 60fps. The SD's were exactly the same, 18fps .

[Lloyd Smale]

that's an odd finding. Ive allways found cci 350s the hottest pistol primer.

[Boogieman]

I still have a few of that lot on boolits left . I'll load some more with the CCI 350 , I want to see if this was just a fluke.

[44man]

I can interchange CCI primers with Fed. The 300's work like Fed 150's and the larger cases from .475 up work fine with 155's or 350's.
Yes mag primers will up velocity until it is not needed, I never load for speed.
Now the SP or SR primers will not act the same and for calibers like the .357 I use what I have.
To plug a bottle with a boolit in small cases and expect tension or crimp to hold it back enough for good ignition can be a mistake. The wrong primer can push a boolit and the powder pretty far first. A primer can add 2000# of pressure.
When I got my .475 there were not many loads in print. The case is made from 45-70 brass with LR pockets. I was told by powder companies in no uncertain terms to NOT use LR primers, pressure issues.
Hundreds and hundreds of tests for more years then I want to claim has shown what works in each caliber.
Load a boolit with no powder, shoot it and see how far it goes up your barrel.
The .454 was a special case using a SR mag primer. Powder at starting book would not light off, driven into the bore and powder packed behind the boolit with hardly any discoloration. Brass rod is still in my bag. Changed to cut down .460 brass with a LP mag and any load worked. Get fire with less pressure until cases get larger. Even the 45-70 works with a LP primer. So does a 30-30.
With my BPCR I put a newspaper disc in first to keep powder out of the flash hole. Primer had to burn a hole through paper first, works fine, LP primer.
My use of a Fed 155 starts at the .454, .475 and .500's. Smaller brass--NO.

[44man]

The .44 mag is still a small case. Smallest revolver I own. Maybe the gun I worked most. Case tension issues and primers. Nobody here can claim 1-5/16 at 200 yards. Sorry, but I even had 3/4" at 200 meters. 3/4" at 100 off hand. Now at my age I shake. You did not fool with me back then.
Cussing on the line from .44 shooters was common. None would listen. The creed was to help but it was no use. Top shooters would go out of their way but it was bumping against a wall. It is here too. Sad to say it.
The worst thing on forums is to say "PROVE IT." I will not do it anymore. Everyone runs to the complaint forum. A thing I would never, ever do to anyone. Bash me and beat me all you want. Can I help?

[ole 5 hole group]

that's an odd finding. Ive allways found cci 350s the hottest pistol primer.

I agree and that CCI 350 is a hot primer. I don't believe any other U.S.A. manufactured magnum large pistol primer comes close to that CCI 350. I don't venture out much in -35*F weather but I have complete confidence in the CCI 350 lighting off a case full of H110 in that type of weather.

[44man]

Cold affects all powders but if you stick your head out the door at -35° you live were I won't go.
I don't know why cars springs don't shatter.