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> pierced primers
pierced primers
@ 01:44 am (GMT) |
Wayne WoodardHi again Guys,Have been developing loads for a 223 and have got a couple of pierced primers at 24gr AR2206h, 80gr Amax, ADI brass. Doesn't appear to be any other high pressure signs, primers aren't too flat, cases not tight. Primers start cratering at 23.5gr. Do I just take this as high pressure and back off? They are around 2900fps so getting up their. Temperature has been 37C plus. My other promising load seems to be 22.6gr at 2725fps. Opinions? Cheers, Woody. |
Replies
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@ 01:46 am (GMT) |
Wayne WoodardRe: pierced primersBugger forgot. CCI 400 primers, first time using them. |
@ 07:15 pm (GMT) |
Alvaro Piqueras Alonso-LambertiRe: pierced primersHi Wayne...I have used mostly CCI primers... here is difficult to get your hands in something different (apart from S&B wich I don´t reccomend). CCI primers are tough, so please take it into account. If you just see a "circle" around the striker mark, don´t worry, it used to accur. If you see them flattering at the edges, be carefoul! |
@ 12:53 am (GMT) |
Bryan WebsterRe: pierced primersIs there an actual hole right through the primer? Or just the indentation mark of the firing pin? |
@ 03:43 am (GMT) |
Nathan FosterRe: pierced primersHi Wayne, yes, been through this myself in .223 many years ago. Yes, the cases have reached max pressure (or rather the primer cup). I think the piercing is more common in .223 due to the large size of the bolts and main springs (and also firing pin protrusion) relative to the small primers.There is a great risk of a gas blow back. Some will vent into the mag well and buckle the floor plate while some may blow back into your eyes. So there is quite a risk, even without action failure. Best to back off to the other load. |
@ 04:04 am (GMT) |
Robert KennedyRe: pierced primersI only read about this problem yesterday in the February issue of "Sporting Shooter" and Nick Harvey mentioned the need for "small rifle magnum primers". He said : " it is absolutely necessary to use small rifle magnum hot .17 centrefires and the .223 Remington as standard primers have softer cups which are likely to be perforated by the firing pin."Being pig- ignorant of this I did a search and came up with this on http://precisionrifleblog.com/2012/07/02/most-accurate-rifle-primers-for-precision-reloading/ Remington 7½ – The only primer specifically marketed by Remington as “benchrest” quality. Lyman & Nosler classify this as a standard primer, but Hornady, Handloads.com, and Chuck Hawks classify it as a small rifle magnum primer. Remington says the compound is the same as the 6½, but with a thicker cup. (6 1/2 cup thickness is.020″, 7 1/2 is .025″) Maybe this is worth investigating? |
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@ 04:13 am (GMT) |
Robert KennedyRe: pierced primersSorry, I left out a couple of words somewhere there "...primers in.."Also the precisionrifleblog says: CCI BR-4 – Very similar to CCI’s standard small primer (CCI 400), but with a slightly thicker cup (.025″ instead of .020″) and stamped “Benchrest” to indicate it is “match quality.” I’ve personally used thousands of these, and have found them to be very consistent. Hope this is a help for your problem. |
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@ 02:56 pm (GMT) |
Nathan FosterRe: pierced primersIf a person was really wanting to pursue these loads, it could be worth purchasing a second firing pin, then making one of the firing pins a bit shorter. Factory firing pins are often longer than necessary to ensure ignition. Definitely want to experiment with a spare pin as the strength of the mainspring is always an unknown.The difference of .005" or .1mm in primer cup thickness is not a great deal but it could be worth investigating. My immediate concern is safety / gas blow back etc. |
@ 03:16 pm (GMT) |
jasonRe: pierced primersThat was my exact pet load, except for the primer I used fed 205 and the ambient temp. It doesn't normally make it to 30 degree here you must be in oz.I didn't have any problems. |
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@ 04:54 pm (GMT) |
Nathan FosterRe: pierced primersI asked Dan at Reloaders Supplies if he could today study the differences in off the shelf rifle firing pin protrusion in .223 caliber rifles. While .055" protrusion is the general rule / goal for sporting rifles, Dan found variations from .0275" to .0790".You can see how such variations would effect penetration into the primer cup. Thank you so much Dan for taking the time to relay this info for us. |
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@ 07:35 pm (GMT) |
Wayne WoodardRe: pierced primersThank-you all very much for the replies, appreciate the time and effort taken. I should have enough info and understanding to work with now. Been doing a few little tests myself as well.The safety/ gas blow back was my concern. I wasn't using glasses at the time and learnt a lesson with out injury, load development is now done with eye protection. Yep, in oz. Was trying the higher loads at higher temp for reference. Cheers, Woody |
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