The Firearms Forum banner

21 - 36 of 36 Posts

·
Registered
Joined
·
3 Posts
An 11 year old thread. There are quite a few NEW ones, asking the same things,that could have been resurrected.
I knew someone would chime in on that but you'd be surprised that this is one of the first threads that comes up on Google in regards to the matter.
 

·
Registered
Joined
·
166 Posts
From what I've read from various sources cci spm and sr primers are the same primer just sold in differant packaging.

I use any sr primers for 357mag but only for bulkier powders that specify magnum primers. Never for faster powders just 296 or LG as they specify magnum primers for those. I typically only fire those powders in a carbine though but have in revolvers a few times with no issues. I dont use light hammer or firing pin springs in my firearms.

Work up loads from low end of scale and work your way up looking for correct pressure and the antisipated fps for that pressure as always with any loading regardless.

When primers are easier to find pop a few empty primered cases off in a handgun outside in low light. No two makes will have the same flame and some sp brands may produce more than some spm or sr brands. Some are yellow or reddish and some blue. Some makes are harder to dent than others some softer.

I'm in agreement with everyone on the lr and lp primers not being interchanged though - any primer must be seated correctly or not used. Deeper seating may no be an issue but you dont want any protrusion esspecially with thinner cups.

As always, I only suggest others do what is stated in the manuals.
 

·
Premium Member
Joined
·
10,148 Posts
There was a video (seemed well done) posted recently that made sense to me. The end result that there wasn’t a measurable difference in power between SP, SPM and SR primers. The difference was in the cup hardness to account for higher chamber pressures. Going from SP to say SR could result in light primer strikes which would be nothing more than a nuisance. Now I’d be very cautious going the other direction ie running SP primers in a rifle.
 

·
Registered
Joined
·
166 Posts
I use SP in sub loads all the time,only lighting off 4-8grs.
If we ever see primers come back, I may load some 38spl cases with no powder, wooded dowel bullets, and crono different types of primers to see if there is any pressure difference between sp, spm, and sr. Some way to measure the heat would be handy though along with the pressure. Years ago I had a astm calorimeter but it is long gone now.

Probably could just crono same loaded ammo with just differant primers and crono the results - any significant differance should show up in the data.
 

·
Premium Member
Joined
·
10,148 Posts
Probably could just crono same loaded ammo with just differant primers and crono the results - any significant differance should show up in the data.
That’s what the guy did in the video I mentioned. With everything else the same he loaded all three primers and there wasn’t a noticeable difference in velocity.
 

·
Premium Member
Joined
·
1,493 Posts
It's hard for me to go against what the suggested info says in the reloading manuals . I have heard and seen lots of experiments on use of primers which sounded pretty solid but think will stick with the manual says . Right now I got enough primers but if or when the time comes I run out of a certain size will probably just do with out . Guess that is when I dig that primer making kit out I bought awhile back . Hey Willie anymore practice done your way ?????
 

·
Registered
Joined
·
328 Posts
I have wondered, if the companies only label the primers differently to get us to buy more?

I need SPP primers.
Pick-up 1000
Hmm, I need to load some .357M, too. I best get 1000 SPM.
I wonder where I am on SR, store stock is low, I will go ahead and get 1000. I mean, it's not like I won't use them.

vs

I need primers
Pick up 1000 Large and 1000 Small.
Done.
 

·
Premium Member
Joined
·
10,148 Posts
I used to rep a factory that manufactured electrical receptacles (like in your walls) amongst other things. They had four different grades ranging from residential all the way to hospital grade and guess what? Other than the packaging and the green dot on the hospital grade they were all made of the exact same components, no difference in quality. It was all due to the cost of manufacturing and it was just cheaper to make the most expensive grade only as opposed to the cost of inventorying different components and the time spent setting up the machines. I would guess primers are probably in the same boat.
 

·
Super Moderator
Joined
·
40,859 Posts
I used to rep a factory that manufactured electrical receptacles (like in your walls) amongst other things. They had four different grades ranging from residential all the way to hospital grade and guess what? Other than the packaging and the green dot on the hospital grade they were all made of the exact same components, no difference in quality. It was all due to the cost of manufacturing and it was just cheaper to make the most expensive grade only as opposed to the cost of inventorying different components and the time spent setting up the machines. I would guess primers are probably in the same boat.
Your post reminds me of when I was a young man, working part time as a service station (back when they actually provided service). Remember the 1156 and 1157 light bulbs for cars? We would sell (and install) either bulb in your car. If you drove, lets say, a chevy impala, the bulb cost was something like $.50, if you drove a caddy, the bulb was something like $1.00, and if you drove a BMW or other high dollar car the bulb was something like $1.50. Same bulb but different price according to your car.
 

·
Registered
Joined
·
328 Posts
Back in '78, I worked with a woman that drove a Cadillac. Her starter went out and dealer told $450 to replace it.
I told her I would it in for a case of beer.
She started calling parts stores, to get a starter. It was $90. I told her to tell them starter for a 1976 454. She says they are asking what vehicle?
I say, " '76 GMC pick-up "

$38 and 20 minutes later, job is complete.

She traded the Caddy, month later.
 

·
GUNZILLA
Joined
·
6,813 Posts
According to Sierra Manual switching the primers around can randomly lead to serious pressure problems.
 
21 - 36 of 36 Posts
Top