Empe
Member
Is it necessary to use small pistol magnum primers when reloading for the .357 or can the standard SPP be used instead ?
Primers for the .357 Magnum
- Thread starter Empe
- Start date
Register to hide this ad
While you could use Magnum primers for all powders there are many that do not need them
H110/296 you better be using Magnum primers
Unique, 231, Bullseye and many others work just fine with standard primers
H110/296 you better be using Magnum primers
Unique, 231, Bullseye and many others work just fine with standard primers
LoboGunLeather
US Veteran
Thousands of rounds of .357 loaded over the past 50 years, but I've never purchased or used magnum pistol primers. I understand that some loads benefit from magnum primers, but I haven't had any difficulties at all.
As others stated, depends on powder. Probably only H-110, WW296, and maybe 4227 require or greatly benefit from Magnum primers. I shoot a good bit of 4227 and notice a reduction in umburned/partially burned powder residue with Magnum primers.
rockquarry
Member
- Joined
- Aug 9, 2005
- Messages
- 8,497
- Reaction score
- 10,427
They both work, but I'd use the one that gives best accuracy, this is if you can see any difference.
pantannojack
US Veteran
Since I got my 586 no dash, no M, last year I have been experimenting with the affordable powders available. All 158g hard cast with GC, some not. I have found HS-7 at 10g (Hodgdon's max) seems a bit smoother with cci mag than wsp std. 2400 and IMR 4227 I use mag primer because they are on the slow end. I have been using 4756, both mag p and std and think it may the high end of neutral. I am just using the "FEEL" of it rather than trusting a 50$ rattling Crony which is not consistant any day or time of the week. I don't seek the edge of the envelope, just an entertainment hand losd that SPEAKS. I am not going out to buy a box of H110 or 296 because of the cost and they use alot of powder but if I did I would use mag p; And a loading book stated "high bullet pull" meaning a stiff crimp. Unique and faster likely don't matter. I think Unique is from the late 1800's and after that I prefer a number'd name rather than a katchy emotionally charged moniker.
DWalt
Member
SPPs are fine for any normal .357 load. But SPM and SR primers (which are twins) will also work just as well for any .357 load recipe.
The .357 case is tall for diameter. I use magnum or small rifle primers with all loads light or heavy, with all powders. There are no drawbacks to doing so and some reloading manuals do the same.
The slowest burning rate powders require a magnum primer, those would be H110-W296, perhaps 4227, I've heard that HS6 works better with magnum primers and likely AA#9. The faster burning powders will do just fine with standard primers.
- Joined
- Apr 29, 2012
- Messages
- 4,477
- Reaction score
- 7,609
The .38 case is also tall for its diameter. Do you use magnum primers in that?
I do for +P loads. Magnum or small rifle primers are pretty much the same thing. They are not dangerous explosive blasting caps folks. If there is some drawback to using them splain it to me. Same price, improved consistency, usually more readily available. Unless you subscribe to the theory that REAL men don't need magnum primers to feel like a man.
Last edited:
smithra_66
Member
- Joined
- Jan 6, 2020
- Messages
- 1,307
- Reaction score
- 2,140
Either one works fine. If you're using slower powders, your volume of powder will be larger, so a magnum is generally recommended for those.
I've found, after 30 years of reloading, that magnum and standard primers are pretty much interchangeable. You might get 10-15 fps more with magnums. That's about it.
I have tried standard, magnum and small rifle primers in my 357 handloads. With most powders a magnum or small rifle primer is not "needed". Although with some load combinations of powder, charge and bullet, magnum primers may make a noticeable difference. If I use small rifle or magnum primers for my normal standard primer handloads, I will do another load workup up, never a straight across substitute...
DWalt
Member
Over 40 years ago I set up an extensive series of tests with .38 Special loads in a K-38. It used a variety of bullet weights, bullet types, and powders. The idea was to see if using SPPs and SRPs made any significant difference in MV. It did not. Of course my notes vanished long ago. I think only CCI primers were used, plus Bullseye and Unique powders. There were several other powders tested, but I do not remember what they were.
- Joined
- Apr 29, 2012
- Messages
- 4,477
- Reaction score
- 7,609
I do for +P loads. Magnum or small rifle primers are pretty much the same thing. They are not dangerous explosive blasting caps folks. If there is some drawback to using them splain it to me. Same price, improved consistency, usually more readily available. Unless you subscribe to the theory that REAL men don't need magnum primers to feel like a man
I just asked a question. I made no insinuation that they were "blasting caps". I haven't found the improved consistency in .38 Special that you have. You're sounding a bit defensive with the insults. I don't think my question deserved two "eyerolls".
I'd rather use SRP than SPM in many situations. I've actually determined they are a tad less intense that SPM. That's somewhat brand dependent.
This is an important point. You can try a different type of primer but need to start load development again at the lower end of the ladder.
I've done many comparison tests with various loads over my chronograph. With loads in the .38 spl or light .357 loads velocity gain with SPM or SR primers will be around 5 FPS or maybe 10 fps in mid range .357 loads. Defensive? It's just that by now this often raised question would seem to have been beaten to death. Some handloaders are so fearful I wonder how they can even bring them selves to dare load their own ammo. And as to going back and working up while carefully watching for signs of high pressure? In loads of around 15-17,000 PSI? Don't think so. Speer manual put this issue into perspective with pics of .44Magnum fired primers in loads of up to 60,000 PSI showing that there are no visual indications of pressure signs until pressures are extremely high. Just read your manuals folks beyond just looking at the load data.
Last edited:
