Cartridge exploded in chamber
- Thread starter Oldly
- Start date
This is correct.
If 25 gr is compressed at 106% then 27gr is about 115% and that's probably not possible. QL guestimate says 27gr with 50gr bullet is 68K psi. So I'd agree it doesn't seem possible that an overcharge of N133 did this.
Sorry, I didn't see that you did say it was a 69gr bullet previously.
Even with a 69gr bullet QL says it would be hard to get enough N133 in that case to get to 70K, and the picture of your brass look to be way past that.
Sorry, I didn't see that you did say it was a 69gr bullet previously.
Even with a 69gr bullet QL says likely not possible to get enough N133 in that case to get much over 70K, and the picture of your brass look to be way past that.
Ya it is a tough one but I'm not sure if benchmark is faster or 335 but those are all my powders besides varget and imr 4895,223 is all I load for.the max viht says for that bullet is 22.9 I also use a toothbrush to vibrate my cases.i seated 2.78 about 30th off the lands.was it 75 instead of 69 I don't think so but you never know.but I've never had a squished primer before because I've never loaded close to max on any load ever.i can say I should of stuck to my first instinct when I told the wife I wasn't feeling up to going to the range,but decided any how to go and reloaded while feeling 30% from 2nd covid vacation.
- Location
- Western Manitoba
Go to the kwk.us site and see pressure numbers for SAAMI and CIP - they use different testing procedures, so not always directly comparable to one another. On that column for piezo numbers - which will be PSI, in 1,000's, they say that SAAMI's limit for 223 Rem is 55 and the CIP's limit is 62. So, 55,000 PSI using SAAMI's testing procedure, and 62,000 PSI using CIP's testing procedure. You will see different numbers in the next columns - again, SAAMI and CIP limits expressed in "Copper Units of Pressure" - "CUP" which are not the same number as "PSI" values, although the load pressure is the same (PSI versus CUP). SAAMI and CIP might set different standards - is what they do - but they also specify how and what they test, which is not the same.
- Location
- Western Manitoba
You might want to note that CIP requires new rifles to be "proof tested" to 125% of their rated load. If you take that thought and apply that to SAAMI 55,000 PSI standard, that would amount to 68,760 PSI as a "proof load", using SAAMI pressure testing procedures. So, if you achieved 70,000 PSI, you are well beyond that level. For reference, that new rifle is to "take" that proof load procedure, without any measurable permanent deformity or alteration.
I have very little, to "no", experience at this, compared to others that have posted here, but the deformities that are shown of that brass casing, is way gone past any "proof load" levels of pressure.
I have very little, to "no", experience at this, compared to others that have posted here, but the deformities that are shown of that brass casing, is way gone past any "proof load" levels of pressure.
- Location
- Western Manitoba
I suspect that knowing a "pressure number" is not very useful for most of us, since we have no way to measure it. I read an article on this by John Barsness. He took a number of his rifles with various factory and hand loads - some that he had been using for years, using his "at home" pressure estimating techniques that many of us use. He discovered at the Western Powders lab, in Myles City, Montana, that his "home techniques" were not dependable. I seem to recall one load, that he had used for years, was over 70,000 PSI, with no excessive primer flattening, hard bolt lift, case head expansion, etc. in his rifle. But he did discover that muzzle velocity was ALWAYS in step with the pressure. His conclusion was that the only way to get more velocity, was to create more pressure - no other way - not a mystical "fast barrel", no secret loading techniques, no cartridge shape. He therefore concluded that using the chronograph was his only dependable way of evaluating the pressures of his hand loads. Apparently, some might disagree with him...
- Location
- Western Manitoba
I do not own Quick Load.
- Location
- Western Manitoba
"pressure" - not sure how discovered, but the length of the "free bore" is and was used to reduce the peak breech pressure. I have a STIGA 30-06, which is built on a Swede receiver - probably an M94, but possibly an M96 - I do not know how to tell the difference. Those rifles have unusually long free-bore compared to commercial 30-06 rifles on other actions. They were proof tested when they were assembled in Denmark, so they were able to use a chambering that might be a bit above the "pressure rating" for the Swede bolt and receiver - due to the length of the 30-06 versus the original 6.5x55, some material was removed behind the lower locking lug recess - making a proof test a very desirable thing, I think. Roy Weatherby did the same with his early "boomers" - a long free bore to reduce that "peak pressure" when fired. I understand a relatively recent cartridge - 338 EDGE +P - was created from similar idea - extending the EDGE freebore dropped the pressure, so allowed more powder to be added. I do not own one - just what I had read.
My understanding might be a bit muddled, but if the breech pressure (PSI) is graphed against time (in milli or micro seconds), it is the "peak" value that will take apart the rifle; it is the volume under that curve (calculus, anyone?) that will result in the bullet velocity.
Up shot is that what "works" in one rifle, might not "work" in another - depending on that free-bore - so someone's "hot load" in his rifle with burned away leade, might be "too hot" in your newer one. Barsness reported in another article of having a rifle with a "custom made" barrel chambered for a Weatherby cartridge - maker did not use the longer Weatherby free-bore - "to be more accurate" - factory Weatherby cartridges would "lock up" that bolt, as a result. So, was burned into my mind a long time ago, that EVERY change in a load - powder, primer, case brand, bullet brand, gets "worked up again" from a Start load level - mostly for my own piece of mind - I no longer enjoy "surprises".
My understanding might be a bit muddled, but if the breech pressure (PSI) is graphed against time (in milli or micro seconds), it is the "peak" value that will take apart the rifle; it is the volume under that curve (calculus, anyone?) that will result in the bullet velocity.
Up shot is that what "works" in one rifle, might not "work" in another - depending on that free-bore - so someone's "hot load" in his rifle with burned away leade, might be "too hot" in your newer one. Barsness reported in another article of having a rifle with a "custom made" barrel chambered for a Weatherby cartridge - maker did not use the longer Weatherby free-bore - "to be more accurate" - factory Weatherby cartridges would "lock up" that bolt, as a result. So, was burned into my mind a long time ago, that EVERY change in a load - powder, primer, case brand, bullet brand, gets "worked up again" from a Start load level - mostly for my own piece of mind - I no longer enjoy "surprises".
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Potashminer thanks I'm not going to try to figure it out anymore,going to get a smith to look at it and go from there.the bolt is fine just needs an extractor spring for the pin,and chamber looks good and the cartridge body was fine except for the base.live and learn.there was awful knofful and evil kneival I was in the middle growing up lol.
