Running low on SPP? Try this...

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dgang

New member
This is going to cause some blowback. If you are loading .38 spl or +P or .357 to be used in a .357 revolvers, Small Rifle Primers work just fine. Load a few up just check to see if your hammer has enough power to strike the primer and set it off. Brisance of a SRP is about the same as a Magnum SPP, and they are exactly the same size.
Down to 2000 SPP to be used in other cartridges and had an excess of SRP and used them in the revolvers. Very slight increase in fps. which I assume corresponds to slightly higher pressure, and the harder cup proved no problem with the .357s.
Trying 9mm bullets in .38 loads, be interesting to see if there is a loss of accuracy. Trying to use everything in my inventory to prevent spending outrageous money in todays market.
 
U

Unclenick

Staff
dgang said:
Brisance of a SRP is about the same as a Magnum SPP...
Click to expand...

Here's some blowback: Brisance isn't a measure of how much pressurizing gas a primer makes. It's an indirect measure of how rapidly the explosive is consumed and is measured by setting off quantities much larger than a primer to see how much sand the resulting shockwave can shatter. It's been described as a "measure of quickness" of an explosive and, for primers, if it gets too high, it can cause piercing and mushrooming. In some instances, the magnum version of a primer has the same amount of sensitizer as the standard one, but an increase in the percent fuel compounds added to make more pressurizing gas for large capacity cases, but the magnum primer's net brisance is actually reduced by that. In the case of Dinol (Diazo Dinitro Phenol, aka, DDNT) used for some time in lead-free primers (though not in the new Federal Catalyst primer), the brisance is much higher than in lead styphnate (normal) and lead styphnate hydroxide (basic) used in conventional non-corrosive primers. It was for this reason the early LPP Winchester 45 Auto NT cases had a double-wide flash hole. It was to vent the rapidly generated brass before it pierced the primer. In small primers the standard 0.079" flash hole seems to handle them most of the time, but not always.

I recommend reading Allan Jone's article on primers. The differences between brands and the frequency with which the formulations change without being announced means all you can prove to a certainty is what current lots do. If you change to a magnum primer or to any other make of primer, drop your load at least 5% if not 10% and work back up, just to be sure.
 
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ghbucky

New member
I took a look in my big box supply store today and they had a variety of Large rifle, and large pistol, but no small primers of any type.

I'm guessing all the small primers are being consumed by ammo production and none is getting to retail.
 
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dgang

New member
Thanks Unclenich, I learn something new every time you write. I will read Jone's article on primers. I do charge the .357 loads at the start amount ( about-10%), no need to do so with the .38+p as they are being fired through a .357 revolver. Not trying to max out the .357 loads, just need some practice range ammo.
 
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hounddawg

New member
wasn't there a post recently about SPP mags and SRP's being the same primer in a different box? Coulda sworn someone posted that. Anyway when the supply catches up just put a sleeve or or two when doing powder orders paying a hazmat fee just for times like these. Don't have to order 100K or anything stupid but a few extra sleeves a couple of time a year during non election years adds up
 
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hounddawg

New member
here is the thread/post I was thinking of

Unclenick

If you call CCI and ask, as I did, the nice lady on the other end will look up their primers and compare component numbers and priming mix quantities for you. But for this one, she knows the answer off the top of her head. The CCI #400 small rifle primers are identical to the CCI #550 small pistol Magnum primers. They are just in different packaging. She said CCI employees buy the #400s for their rifles and handguns all the time so they can buy a bigger quantity at a time and stock just the one.

If you haven't been using a magnum primer in you gun, back the charge down 5% and work back up to a velocity match to your usual load
Click to expand...

post # 21 of this thread

https://thefiringline.com/forums/showthread.php?t=607981&highlight=cci
 
H

hounddawg

New member
argue that with UncleNick if you want an argument, he posted that 2 months ago. I have plenty of both types could not care less at this point
 
7

74A95

New member
hounddawg said:
it's the same thread, his post 21 is what I cut and pasted
Click to expand...

I'm sorry you can't understand what you're reading.

They are two different threads.



Here's what he posted July 31, 2020 in the thread i linked,

"My information was outdated

I just spoke with CCI, and learned my previous information is out of date. Apparently the designs have changed since I last spoke to CCI about this (still can't recall how long ago, so I don't want to guess and give someone bad date/age information). The current information is that CCI 550 and 400 primers now both use different priming formulations and have different quantities of priming mix in them and also that the current 400 design uses a thicker cup than the current 550 design. So what I said before should be ignored and attempts to use the 400 in place of the 550 will require new load workups. I think CCI is exaggerating to say, as the tech did over the phone to me, that the substitution is playing with dynamite. I have never seen primers cause that much difference, but there may be some funny circumstances where this can cause a problem, so caution is important."
 
A

Average Joe

New member
All my revolvers and lever rifle (.357) use SRP's , been doing this for years now with no ill effects, all you need is a good hard smack on the primer and it will work just fine.
 
J

Jim Watson

New member
In the one 9mm load I tried with different primers, there was NO difference in velocity with 7 out of the 8 primers tried, rifle, pistol, magnum, standard. The one slightly higher was with Remington small pistol.

Before they started making magnum pistol primers, Federal recommended their small rifle for .357 magnum.

I have quit worrying about it. I don't load to maximum and don't have to "work up."

By the way, how do you "work up" a pistol load? How do you know you are enough "up?"
The "pressure signs" that people think they are seeing in a rifle are indications of gross overload in a handgun.

I use a gun and a chronograph for three levels.
1. Just enough to cycle the slide on an automatic.
2. Power factor for IDPA and USPSA.
3. Factory equivalent.
If I can't equal a factory load at a published powder charge, I use something else.
 
A

Average Joe

New member
I don't have a chrono, so I do it the old fashion way, I go by best groups from the various powder charges up to max load from the powder manufactures data.
 
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