.38 special w/ Magnum Primer

[savit260]

Seems like everyone localy is out of regualr small pistol primers.

I have about 600 Magnum primers on hand.

Tried out a few rounds 3.0 grains of HP-38 with Winchester Magnum s.p. primers and a 158gr hard cast SWC. Found it to be VERY accurate in my Colt.

Does anyone know if there is a reason why I shouldn't use this load?

Is there a signifigant differance using the Magnum Primer?

My assumption is that it would be a hotter primer, and to back the powder off a bit from a standard load.

This seems to be a very pleasant load, and the accuracy was very good.

Any comments/advice would be appreciated.

Thanks.

 

[philbo]

Genral rule whenever you change components is to back off and rework the load exactly as you hae done. Start load is 3.1 grains of HP38, so no danger of overpressure even from the slightly hotter mag primer. If it serves your purpose, load and shoot.

 

[Ben Shepherd]

You can do it just fine in a pinch, just like you're thinking. But if you are anywhere near the top of the charts back the powder charge off a bit.

A chrono would be a wonderful tool to have in this situation.

 

[pmeisel]

the magnum primer is hotter, but with backed-off loads it shouldn't matter at all. Some experimenters report more variation in velocity which could affect accuracy a little, but it shouldn't matter for normal recreational shooting.

 

[Walkalong]

Does anyone know if there is a reason why I shouldn't use this load?

Nope, it should work fine. You are way under max. If it shoots well for you, go for it.

 

[savit260]

Thanks for the advice.

 

[Lariatbob]

No problem on a large case like .38 or .357. Rule of thumb is .1 gr less when using magnum primers. I usually don't even worry about it, never a problem.

I do not use them on smaller cases like 9mm or .380.

 

[Snowboy]

If it can help, I tried both once to see the difference

Note that these have been tested in .357Mag cases

SPM go a little slower than the SP ( I mean I didn't invert the data)


38 Special -.357 158GR LSWC
Federal Small Pistol
4,0GR Win 231 OAL: 1,588"
FPS: 737 SD: 20,4

Federal Small Pistol Magnum
4,0GR Win 231 OAL: 1,588"
FPS: 712 SD: 23,6

 

[Landric]

I found the standard deviation on my loads was univerally lower when I changed from standard to magnum primers leaving all other components the same. I only saw a significant increase in velocity in 9x19 and .32 H&R Mag. In both cases the increase was about 50 fps. The other loads, while more consistent, had about the same velocity average as the standard primer loads.

 

[OrangePwrx9]

I load .38 Spcl, .357 and 9x19 and have standardized on magnum small pistol primers. But, for .38 and 9x19 my loads are never near the top of the chart....always midrange or less. Never had a problem.
Bob

 

[fecmech]

Just to take this topic one step further here is a post I made on the Cast Boolit board regarding small pistol primers vs small rifle primers. As you can see not much difference over the chronograph.

Due to my inability to buy any small pistol primers on a recent trip I bought 3000 CCI Small Rifle primers instead. I still have about a years supply of small pistol primers but I was getting nervous. Today I loaded two of my most accurate loads in the .38 and .357 for my Model 94 winchester to see what if any effect the SR's would have on my loads versus the SP's. The primers were CCI 400 Small rifle and Mag Tech Small pistol and the powders were Unique and WC 820 ( this lot mimics my 296).I fired 10 shots each of the bench using a rest and a peep sight over the chrono screens at 50 yds. Due to some incoming rain I fired fairly quick but as accurate as I could. As I expected the Unique SR load had a higher es and sd than the SP load but the group was slightly better which surprised me. The SR load in WC 820 was super uniform and more accurate than the SP load putting all 10 in 2.25"@ 50 yds. The . 38 load used the H&G #39 RN 158 gr and the WC 820 used Lyman 358429.

5.1 Unique/SR Prime
High--1124
Low--1036
ES----- 88
SD-------25
Avg 1079

5.1 Unique/SP

HI 1091
Low1047
ES----44
SD---- 12
Avg 1066

14.9/wc820/CCI SR
High- 1677
Low 1653
ES-- 24
SD---- 6
Avg 1667

14.9/WC820/SP
High 1682
Low 1633
ES-- 49
SD--- 15
Avg 1662

I loaded some of the CCI SR primed .38's in my K 38 and fired two cyls full DA and had only one misfire which was a nice surprise. My K 38 is my old PPC gun which has a nice 8 lb DA trigger.
All in all I think the small rifle primers will work out just fine till the SP's become available again.
__________________

 

[Ben Shepherd]

Fecmech a question-

I'd bet the crimps on the unique loads were light, and fairly heavy with the wc820?

 

[fecmech]

Nope--I run a light taper crimp on all my .357 handgun loads and bullets don't walk out of the cases in my revolvers. I went through the heavy roll crimp vs the taper crimp quite a while ago, and I'm talking serious roll crimp. IMO it don't matter and I've never seen it over the chrono. Also IMO whats important is bullet pull and that's determined by sizer die, expander plug and the actual brand of case.