Magnum versus standard LP primer

Started by 10 Round, July 04 2025 02:17:20 PM MDT

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10 Round

I have some old cci, large pistol magnum. Primers, i've been restocking with new these old primers were dated 97. I was running a hundred of these to see if they were still good, they are.
I'm running nine point seven grain's of aa #7, and I ran them with standard fiocchi, primers and the cci magnum, primers, the magnum primers, leave the brass completely black carbon all over the outside, not as accurate, as the fiocchi, and the fiocchi's leave the brass almost completely clean. Are the primers just too hot for that load of powder and 180gn bullet in a g29 short barrel.?

crockett

Quote from: 10 Round on July 04 2025 02:17:20 PM MDTI have some old cci, large pistol magnum. Primers, i've been restocking with new these old primers were dated 97. I was running a hundred of these to see if they were still good, they are.
I'm running nine point seven grain's of aa #7, and I ran them with standard fiocchi, primers and the cci magnum, primers, the magnum primers, leave the brass completely black carbon all over the outside, not as accurate, as the fiocchi, and the fiocchi's leave the brass almost completely clean. Are the primers just too hot for that load of powder and 180gn bullet in a g29 short barrel.?


Those magnum primers are fouled due to contamination from humidity and / or chemical degradation, causing incomplete burning of the powder, resulting in lower chamber pressure, and that prevents the brass from expanding fully in the chamber, so you get to see dirty blow-by, leaving carbon on the outside of the brass behind.

Usually magnum primers cause a pressure spike and more case expansion - not less - so they must be foul.

If stored at constant low temperatures, in low humidity and sealed, they often do last longer.

10 Round

Quote from: crockett on August 10 2025 03:55:40 PM MDT
Quote from: 10 Round on July 04 2025 02:17:20 PM MDTI have some old cci, large pistol magnum. Primers, i've been restocking with new these old primers were dated 97. I was running a hundred of these to see if they were still good, they are.
I'm running nine point seven grain's of aa #7, and I ran them with standard fiocchi, primers and the cci magnum, primers, the magnum primers, leave the brass completely black carbon all over the outside, not as accurate, as the fiocchi, and the fiocchi's leave the brass almost completely clean. Are the primers just too hot for that load of powder and 180gn bullet in a g29 short barrel.?


Those magnum primers are fouled due to contamination from humidity and / or chemical degradation, causing incomplete burning of the powder, resulting in lower chamber pressure, and that prevents the brass from expanding fully in the chamber, so you get to see dirty blow-by, leaving carbon on the outside of the brass behind.

Usually magnum primers cause a pressure spike and more case expansion - not less - so they must be foul.

If stored at constant low temperatures, in low humidity and sealed, they often do last longer.
That is a very good possibility. I will do a test today. I loaded five brand new regular primers, five of the old magnum, primers, same load this time, and I will check for blow by. On the other test, I was loading very low powder levels. So that's a possibility. I will find out today and do some speed testing. Now, one other goody, I just changed powders, i'm trying to get rid of some 700x.

10 Round

Well, I saw no darkening using either primer, so there was no blow by, I really believe I was shooting a super light load be86, it would eject, but it wasn't expanding All the way. No discoloration, on either load, I had about 18 feet per second difference in the two loads 6gn 700x 180 rn sure is a wimpy load but I want to get rid of that one can of 700X.

crockett

Quote from: 10 Round on August 11 2025 12:12:59 PM MDTWell, I saw no darkening using either primer, so there was no blow by, I really believe I was shooting a super light load be86, it would eject, but it wasn't expanding All the way. No discoloration, on either load, I had about 18 feet per second difference in the two loads 6gn 700x 180 rn sure is a wimpy load but I want to get rid of that one can of 700X.

And I thought I'm the only one being stingy with supplies, even when I want to get rid of a certain kind. ;D

RedTeam98

In 10mm always use CCI 350 Mag with AA9

10 Round

Quote from: crockett on August 11 2025 03:14:40 PM MDT
Quote from: 10 Round on August 11 2025 12:12:59 PM MDTWell, I saw no darkening using either primer, so there was no blow by, I really believe I was shooting a super light load be86, it would eject, but it wasn't expanding All the way. No discoloration, on either load, I had about 18 feet per second difference in the two loads 6gn 700x 180 rn sure is a wimpy load but I want to get rid of that one can of 700X.

And I thought I'm the only one being stingy without 7mm supplies, even when I want to get rid of a certain kind. ;D
Not only that but I'm shooting large rifle primers in 10 mm to get rid of them I had a thousand and I don't hunt much anymore and I'm shooting small rifle primers and 9 mm to get rid of them.  I also have four boxes of small and large pistol primers the date back to 97 and 98 those are next to get rid of them

sqlbullet

Going forward small rifle is the only small primer I will buy.  They seem pretty much equivalent to small pistol in pressure/performance, and even my Fusion with a light mainspring sets them off without issue.  I don't see a reason to stock both.

I have plenty of large pistol at the moment.  But if large rifle seat without a wobble I would not hesitate to use them.

crockett

My OCD won't let me do that. I have equal amounts of SPP, LPP, SRP, LRP, the magnum versions, and the benchrest versions. My stash looks like a perfectly restocked Wal Mart at 6 AM sharp.  ;D

10 Round

Quote from: crockett on August 26 2025 06:41:56 AM MDTMy OCD won't let me do that. I have equal amounts of SPP, LPP, SRP, LRP, the magnum versions, and the benchrest versions. My stash looks like a perfectly restocked Wal Mart at 6 AM sharp.  ;D
Yes I would not normally do that either but I have stuff that has just been sitting and it needs to get used I shoot at least 20 rounds a day either 9mm or 10mm  when you have stuff that's at least 25 years old it needs to be gone I've got 10 to 15,000 regular primers new I also have 8 lb of 700x and 8 lb of 800x that dates back to the 90s

The_Shadow

I understand that the small pistol and rifle primers are the same size physically.
However the Large Rifle primers are (0.123"-0.133") are slight longer than the large pistol at (0.115"-0.125")

Here are some primer size charts:





The "10mm" I'm Packin', Has The Bullets Wackin', Smakin' & The Slide is Rackin' & Jackin'!
NRA Life Member
Southeast, LoUiSiAna

10 Round

Yeah I know they seat 1, 000 to 3,000 low instead of 6 to 10 and they shoot fine no misfires I have been checking each case for depth

10 Round

I have 100  7mm Remington magnums loaded I'll save for 400 primers but I just don't need a few thousand sitting around.


RedTeam98

In 10mm Auto with AA9 powder I always use CCI 350 primers and heavy dose of powder for 1250 fps in G20 with 190gr / 200gr bullet