Winchester SpMP

[The Shoota]

The other day I saw two boxes of a thousand each Winchester Small Pistol Magnum Primers on the shelf.In my excitement to find anything at all I bought them without really taking note of the word Magnum.
I weighted and measured my other two primer types and found all three to be of identical weight and dimensions, so I know they will fit in my 38 or 357 cases.
Would I be better off using a 357 magnum case and loading a real soft magnum load?
Or can I use them in a 38 spl case, loading a normal target load? Powder is APS 450.
I suppose I could also use a 38 spl load in a 357 case, no?
You can tell I am confused ,right ?
Who can help me out?

[brett]

ive been reduced to switching to small pistol magnum primers too. unless your loading max loads i wouldnt worry too much. i read an article about a guy switching to rifle primers without issue. watch for pressure signs obviously and proceed with caution.

[bladeracer]

I doubt there'll be a measurable difference, but try a few and see. I use the Winchester LPM's in my LP cartridges, saves having to buy two types of primers, I do the same with LRM's in all LR cartridges.

[boingk]

I've used small pistol, small pistol magnum and small rifle in 357 Mag and 450 Bushmaster loads before.

Honestly hard pressed to tell the difference apart from the box and colour.

- boingk