how did this load go from safe to dangerous?

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I haven’t seen anyone mention possibly a difference in OAL. I don’t know your procedures when loading but it sounds like you are extremely methodical and careful but I will mention this anyway. I came across this article in the May-June 2005 issue of Rifle magazine regarding the dramatic rise of pressure as the oal increases in the 300WSM cartridge. Pressure rose from 59,200 to 62,800 using H-4831sc just by increasing the oal from 2.82” to 3.00” and from 59,500 to 63,500 using RL-22 and the same increase in oal. It is very possible that 4350 powder is doing the same thing if by some chance your oal increased between the two batches of ammo.
I don’t know if there is anyway to post this article here but maybe I could attach it to an email if you think this is a possibility and you want to contact me.
Anyway, just my thoughts.
Lkbenson
[email protected]
 
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dakotasin .........

The primers "alone" show that your load may not be as hot as you think. However, due to the fact that there are lawyers behind every blade of grass in America, I'm not going to say this is a safe load in YOUR particular rifle.

I recommend working up your load again with a different lot of primers (not a different box of primers) .... a different lot. You might also want to try another lot of powder, again not a different can ..... use powder from another lot. Measure and compare the size of the flash holes in your cases. That can blow primers with mild loads.

FWIW your pictures also show that the diameter of your firing pin appears to be too small for your bolt, and the protrusion of your firing pin is very shallow.

- Innovative
 
looking for reasons why a load that has fired dozens, possibly 100's of rounds safely and without incident suddenly went from normal to pierced primer.
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Check the loaded rounds neck diameter. Should not be larger than .344" . Trim length ok? Not seating into the lands?
the cases have 3 full power loads fired
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Case life can be as short as 3 loading when at maximum. Has the web area of the brass expanded? If so, another sign of pressure. Yes, could be thin or brittle primers, not ever primer would be bad. Maybe only 3%
 
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There is always the dostinct possibility that your load is perfectly safe, and the primers are at fault.

If bolt handle lift was normal, that would be my first suspicion.

If it is a bad lot of primers, it wouldn't be the first time for CCI.

I quit using CCI about 30 years ago, because of quality control issues.

Just a thought. Remington 9 1/2 primers meet Milspec. you might try working up that load with Remingtons.
 
The primers "alone" show that your load may not be as hot as you think. However, due to the fact that there are lawyers behind every blade of grass in America, I'm not going to say this is a safe load in YOUR particular rifle.
Click to expand...

I'll use that statement to preface what I'm about to say.

If I knew how to put that notice up that reads " The following loads are above published max, do not use them in your rifle"

When I saw this last night,I did the same research Steve did in my manuals. I was shocked to see how the load data for the 300 WSM has been dummed down or lawyer-ed to death.

I have a Browning 300 WSM in an A-bolt hunter, one of the first to hit the area back in IIRC 2002. There was almost no data available for loading and no brass. Factory shells were also scarce, but I managed 3 boxes to shoot for brass.

Enough history! I have fired loads well above what dakotasin is having problems with, WITH NO PRESSURE SIGNS!. I was using XMR-4350 a lot during my initial experiments. It's load data is slightly higher than IMR-4350, but I went as high as 68.0 behind a 165 Hornady interbond. Chronographed @ 3207 average with an ES of 8.6

The 300 WSM should do 3150 fps with any 165 grain bullet. The fact that none of the data I saw last night had it even breaking 3100 proves there ARE lawyers behind every blade of grass!:cuss:

Dakotasin, your next move should be to size each of those shells that you THOUGHT were excessive in pressure. Then attempt to re-prime them. If the primers seat with normal pressure, then you're not over pressure!

Again, we're trying to read pressure by primer appearance. Those primers don't look like high pressure to me. The edges are still rounded, the backs are not severely flattened. My take is that you have some firing pin issues, the hole in the bolt is larger than the pin.
 
dakotasin,

My thoughts. Your primers do not exhibit typical signs of high pressure. Things to check: with pierced primer, check tip of firing pin; check case length; check fired case neck diameter .vs loaded round neck diameter. Personally, I know you know your way around a reloading bench, so this situation has me stumped.

Don
 
loaded round neck diameter is .336".

i didn't trim these prior to loading, but did check the length on every one and they all measure 2.091 - 2.095 (book calls for 2.100 max).

bullets are not seated into the lands (hunting rifle - i have to be able to function reliably from the magazine and possibly have several load/unload cycles in a day's hunt).

lkb - different oal's aren't a possibility because i make a dummy round, marked w/ the specific rifle and bullet on it, and keep it w/ the die box so i can always return to that seating depth. further, i don't believe differing col's were possible because the first 5 of this lot fired without incident - and the subsequent rounds were seated at the same sitting as the first 5.

innovative & cheygriz - primers are tough. kind of got married to cci during the obama scare because nothing else was available. locally, cci is the only primers available to me right now, and if i drive to the city, cci is the only game in town w/ very sporadic availability of other brands.

snuffy - that is about when i got this rifle. seems to me the first factory loads available were loaded very hot, and i had worked up a 180 grain load to 3150 f/s w/ rl-19 (could be mistaken - don't recall velocity for sure but i remember the load was damnedably hot by today's standards and i never blew a primer).

ussr - i'll get a few measurements here and check back. thanks for the vote of confidence! the pierced primer has shaken mine a little.

appreciate all the help, fellas...

what about headspace possibilities?

cheygriz speaks of poor cci qc... i'm kind of onboard w/ this - anybody else?
 
cheygriz speaks of poor cci qc... i'm kind of onboard w/ this - anybody else?
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You fire less than 20 rounds, get one pierced primer, and it is the primer manufacturer's fault? I will believe this if you fire a lot more rounds and never ever experience a pierced primer. Then we can state, hey, you had a bad primer.

Until then, I am going to believe it is because your load is too hot.
 
what about headspace possibilities?
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Brass would show a thin shiny ring near the case head or in the body. I feel its not headspace related.But,the firing pin strikes do seem off center, at least how i see it.:confused:
cheygriz speaks of poor cci qc... i'm kind of onboard w/ this - anybody else?
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Out of 1000 primers, maybe 3% will fail if that lot # is bad. IMO. I have had bad primers blow out, but on the side of the cup, on the rounded edge. Pressure has nothing to do with this type for the most part.It thins more there on forming. A brittle/thin cup will crack giving a pierced primer. But you also have some flowing back into the firing pin hole. My best guess is something is causing a pressure spike in some rounds and not other.Or bad primers.:scrutiny: No expert here, just my 2cents.:)
 
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Opinion .... I have had over pressure loads in my 270 WSM and I say 270 WSM because I don't own a 300 WSM and can tell you none have ever looked like those! All my OP rounds have had the primer edge radius flattening in the typical fashion pattern. There appear to be no flattening of the Caliber stamping or ejector hole marks. I believe you may have got some thin primer cups somehow, I say thin, but they must only be thin in the center of the primer. If they were thin all over, then we would have seen some flattening of the edges, if it was OP. It appears that you are close to having an over size firing pin hole too. That combination of thin primer face and over sized firing pin hole would give you the exact conditions that your primers show.

As I said, just my opinion.

Jimmy K
 
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dakotasin,

Just an observation, but that primer to the left of your pierced one was definitely about to turn itself inside-out. I've pierced a few primers while working up 80gr loads in my AR-15, and that one there is screaming "BACK OFF"!

Other than that, I have no new suggestions for what could have caused the sudden pressure spikes. Check your firing pin tip now though; it was probably etched during the pierce. If you get another blown primer (or three), you will start piercing on much lower, "safe" loads because of damage to the pin. It is possible your firing pin hole in the bolt is close to max-spec and your firing pin is a bit undersized.

As for primers, I switched to CCIs for .223 loads, because Winchesters weren't holding up to my 77 and 80gr loads, just above starting loads! :rolleyes:
 
243 - yes, the firing pin strikes are certainly off-center - but not much worse than most other factory guns. it may be something that could use attention, but i don't see it as a contributor here?

slamfire... 20 rounds in 1 day. many, many rounds since i concocted the load. i am not blaming cci for anything; just trying to see if it is a possibility.

fired necks measure .344, expansion rings of all cases measure .554 - .555. firing pin protrusion is .048 (probably time for a new pin and/or adjustment). as near as i can tell, the firing pin hole is appropriately sized, but i do not have the tools/skills to measure the hole size accurately.

i did not see any obvious defects on the pin - how obvious is etching on the pin going to be?
 
firing pin protrusion is .048 (probably time for a new pin and/or adjustment).
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Possibly some debris has lodged itself inside the bolt(from the primer that had ruptured), stopping the firingpin's full travel.
That may leave a gap around the FP, for following round/s primer to crater into.
Even make the FP strike off centre.

Or maybe something was already floating around in the bolt and caused the rutured/pierced primer aswell.

Just throwing some ideas at ya.
 
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Induced excessive headspace.....

Remove and clean your bolt face with a bronze bristle brush.

If you'll look closely at the cratered primer/case and the pierced primer, and the case in the loading block immediately to the left of the cratered primer, you'll see a slight "crease" on the primer.

This is caused by a small sliver of case brass that's been sheared off by the extractor/ejector. It's spacing the cases just far enough forward in the chamber that when the round is fired that the primers are backing out and then being forced back into the primer pockets by the back-thrust of the case against the bolt face from the force of being fired.

I see this all the time with full-length sized .30/30's. You'll have a cratered firing pin indention, and a backed out primer. When pressures start getting a little bit higher, the case will be stretched and primers are forced back against the bolt face and reseated in the pocket.

These slivers of brass are what cause the Remington extractor failures.....

At least thats what I see..........

You won't believe how many jammed Remington M742's I've seen through the years with busted extractors. Even saw one that'd had a case head failure due to dirty chamber and bolt head full of brass shavings. Even declined to charge a "night-hunter" with hunting because there's no way the rifle he had would have even fired. I had to soak the action in WD-40 and use a wooden mallet to get the action open on a stuck fired case to "unload" the fired case stuck in the chamber. I had the judge "sentence" the out-of-state hunter to attend a hunter safety course, so he'd learn to how to clean a gun......

No insinuation towards Dakotasin; I know him to be a gun-saavy person. I've had the same "issues" too. BTDT.
 
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i did not see any obvious defects on the pin - how obvious is etching on the pin going to be?
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Small hole in the pin face, like cut with a tiny cutting torch, or its no longer rounded smoothly, a flat spot. But to do this, the pin must punch thru the primer & be in contact with hot gas. What i think happened to you is the part when the pin hit, broke out of the primer and stayed on the pin face area till you opened the action, no gas cutting this way. Not a true pierce primer. Sigh of brittle or thin primer cup.
 
i have to coach a soccer game tonight, and then i'm going to try to get a pic of the bolt head up. i think the creases goose is referring to are actually defects in the bolt face that have been there since the gun was new. but, in the interest of being on the same page, i'm going to see if i can get a good pic and then put it up.

haven't had a chance to size and re-prime the high pressure loads yet, and probably won't tonight, but that is very high on my list of things to do...
 
for closure: took the misbehaving rifle and ammo to the range tonight for some more test-n-tune.

the first cartridge shot a little over 3100 f/s (this was the one i pulled, weighed, and then re-assembled w/o re-sizing the neck - not surprised at the velocity). the next 3 all shot 3150 f/s +/- 5, no pressure weirdness - either primers or sticky bolt. then i ran 12 thru the gun as fast as i could load and shoot. first 11 all shot 3145 - 3160 f/s, the 12th one dropped to 3109 f/s and had sticky extraction and a cratered primer. as you might imagine, the barrel was piping hot by the time this one fired. however, i was unable to duplicate the condition that brought on the original question.

i let the barrel cool, and then slow fired another 15 rounds, 60 seconds between shots, 5 minutes between groups (temp was in the 40's tonight - barrel heating was absolutely not a problem using a slow fire method). 2 out of the 15 spiked velocity up into the 3280 f/s range, and cratered the primer.

so, i took the remainder of what i had and ran them thru a different 300 wsm. the velocity was right at 3110 f/s, no bolt stickiness or other weirdness.

the cases are in the tumbler now - i'll size and prime them later tonight. we'll see how primer pockets feel. regardless of the outcome, i'm going to re-work the load around rl-17 and go from there. it would appear that i am just not getting enough consistency out of imr-4350 to continue its use in this rifle. we'll see what happens as i work thru the rl-17.

btw... primer pockets are all fine.
 
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As I was reading through all this I was wondering about the condition of the firing pin... But since that seems to of been sorted out I am leaning towards either seating depth or case volume.

Weigh the cases that you had issues with and compare them to ones that didn't. If you really want to get picky, fill the cases with water and then weigh the water and compare.

I guess it couldn't hurt to check the diameter of you bullets either, you could of gotten a few that we slightly out of spec...
 
Where did you get the primers? Here is a possibility that happened to me:

I went to bass pro and purchased 200 primers, they were on the shelf in their individual sleeves. When I got home I opened a sleeve to load up some rounds and notice very quickly something was wrong. I had a mix of small and large primers in my sleeve. Some goof ball had opened them up and spilled out some and apparently a worker just filled the boxes with the mixed spilled primers from all makes and models. (I tossed those since BP will not take back powder ammo or primers)

Could it be possible someone opened a sleeve of yours and dropped a few and someone came back later and just picked up the loose primers and put them in sleeves maybe putting some large pistol primers in with your larger rifle primers before you purchased the box?
 
I ask in post 22 >
How far are you seating bullets off the lands? If your only off by .005" with a clean barrel, a dirty barrel can raise pressure.
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You said
bullets are not seated into the lands (hunting rifle - i have to be able to function reliably from the magazine and possibly have several load/unload cycles in a day's hunt).
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Reloading presses can cause a seating depth to vari as much as .005". So i would double check to make sure your loaded rounds do not come in contact with the rifling. Maximum COL 2.860" I would look at bullet seating depth, to close to the lands/rifling to cause this>
2 out of the 15 spiked velocity up into the 3280 f/s range, and cratered the primer.
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Think of Weatherby rifles with the extra free bore, more bullet jump, used to reduce pressure.
 
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There is always the dostinct possibility that your load is perfectly safe, and the primers are at fault.
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That is my thought. I've run into that with Winchester primers. Some were just weak, got flattened or even pierced, while most were fine, and totally random. Shots 1-13 might be fine, #14 flattens, 15-36 no problems, #37 pierced.

Another thought. It seems that all your brass is the same, but what about the flash holes? An oversize flash hole can give false overpressure signs looking at the primer.
 
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