MAG primer with surplus WC820

[bradh]

Does WC820 require a magnum primer in 357? I am loading 11.5 grains. 158 gr cast boolit.

[frnkeore]

Yes!

Frank

[perotter]

I've never used a magnum primer, except for some testing, in a .357 using the WC820 I have. But I could be convinced that I should be, if given the facts as to why.

[buckndee]

Squib Loads!

[MT Gianni]

158 gr is at the minimum end for 820 IMO. If the bullet is heavy enough say 200 gr it may not be necessary for the mag primer. I think it is all about the length of time the pressure string happens in the bbl for ignition here. I like the powder but it needs pressure to burn completely and you can get it from heavy for caliber or a magnum primer but you may need both.

[TCLouis]

I have some VERY old WC820 (H-110 speed) and no Mag primer is required in 357 Mag, 357 Max, 44Mag,
but my newer batches of WC820 (AA# 9 speed) will not reliably ignite in any pistol cartridge without more powerful primers. I use WSR in the Rossi 92 and if I ever use any in the 44 Mag, I will use some WLP Mag primers I ended up with in a trade.

[Lloyd Smale]

are they needed no. At least not if you run full power loads with heavier bullets. but if you reduce at all or are shooting lighter bullets then it is about mandatory. If you doubt this run some over a chrongraph. Ive seen wild spreads with even slightly reduced loads. Even with the heavies or high pressure loads i get better accuracy with cci350s then any other primer so anymore i dont load 820 or aa9 (same thing) without a 350. If anything its harder to light off then 110/296

[bobthenailer]

I personaly only use mag primers with WW surplus 820 . ive used maybe 30 lbs over the years in 357 & 44mg and 454 casull as well as 22 hornet,30/20 & some in 38 super
ive seen people use std primers with good results in the hot to warm weather but when it drops below 40 or so degrees you most lickley get a squib load with alot unburned powder in the cyl & barrel.

[fecmech]

I have the 110/296 speed 820 and with 170 gr bullets in the 15 gr range (.357) it works ok with reg primers but much more uniform (single digit sd's) with small rifle or sp mag primers.

[mdi]

I have some WC820 that is labeled "10% faster than H110", "Reduce H110 loads by 10%". I started with CCI standard primers but "seemed" to get erratic ignition (I don't have a chrony so it's just my "feel" and results on the target that I'm going by). I switched to CCI LP Magnum primers and all is well...