Mistake - HOT LOAD?

[sithlord6512]

Should a gun that has shot a very hot load be "retired"? Alternatively, has anyone experienced a catastrophic gun failure firing "safe loads" after firind a very hot load?

How hot? I was testing H4350 loads with 165 TSXs in my Rem M700 .300 WSM and one of my loads registered 3380 fps (obviously relaoding mistake made somewhere - 305 fps faster than my projected Quickload max velocity). I had to beat the bolt with the palm of my hand to get the bolt to open, the case head expanded so much that the case did not eject because the case rim was getting caught up on the "extractor" (the protrusion on the sidewall of the boltface) - had to pull the case off. Once I got it off, the primer fell out of the primer pocket. Very clear "ejector" mark observed on case head.

I've test-fired 17 reloads since then - low charge to max loads of my 180 TTSX H4350 recipe of 63.0 grains (safely, off course- rigged a weighted Caldwell rest with fishing oine). No noticeable difference in closing the bolt, openning the bolt, and ejecting spent rounds. Headspace measurements of the spent cases have not exceeded my previously measured headspace measurements - In short, no evidence of "obvious" lug setback (understand that lug setback may still have occured dispite contrary evidence).

I could kick myself - I just got the gun back after having a new H.S. precision stock inletted, bedded and installed by a gunsmith. My loads were prepared about 4 months ago - don't know what went wrong. Too much powder (my suspicion)? Did I forget to wipe the lube off the resized cases? Did I use a 180 TSX instead of a 165 TSX? In any case, a lesson, and a potentially expensive one, well-learned.

 

[Elkman]

Others here will probably have different advice, having to open the bolt pounding with your hand certainly show excessive pressure, but you did not mention case seperation, blown primer, stuck case or any other of the more severe signs of pressure. If I were you I (has been a time or two or more in 50 years) I would take it to a smith and have them go over it closely to check for cracks or stress marks. Having said that when I have had to drive the bolt open with a rubber mallet or piece of wood, I made the inspection and continued shooting the rifle for many years, in fact I still do. :grin: :grin:

 

[Guest]

Hopefully Fotis or Dr. Mike or someone can run a QuickLoad simulation for you and you can get an idea of what pressures you were running to get 3300+. In all likelihood you're alright. Proof loads are about 100-120kpsi, and I suspect you were hitting something like 80-90kpsi with your load. I did the very same thing with and overcharge of IMR7828 in a 7mmRemMag several years ago. Learned a lesson - never get distracted at the load bench. If I get interrupted, I now reset everything on the scale to zero, double check the book, and set up again in order to maintain safe control. And, if I've got a charge thrown prior to the interruption, I use it as a "check charge" once I get the scale re-set. Of course, if you accidentally used a 180gr, that's a different issue entirely.

The fact that you were able to open it by hand (and didn't require a mallet and a board) is good. I'm assuming the ejector isn't stuck in the bolt body and everything actuates appropriately? If not, you have problems. If so, again, this corroborates that you just proofed your gun, and nothing bad happened. Of course, you don't want to proof it more than once...

Hopefully someone with QL can give you some intel on how bad it got in the chamber.

 

[SJB358]

I had a similar incident happen with my 264. Very stiff bolt opening and just plain perplexed me. It was the same charge as the week prior, matter of fact it was 3 out of 6 from the previous week. The only thing that changed was I cleaned the rifle before bedding it and I don't think I thoroughly mopped the chamber out, and since the chamber likely had enough lube in there to not allow the brass to grab, I got hard bolt lift. It was a lesson in making sure the chamber is as dry as possible after cleaning, but again, it still shot fine and I don't believe any lasting damage was done. Mike told me that overloads are cumulative and numerous times will weaken the metal. I measure everything on a RCBC 10-10 and always eyeball my case loads before seating bullets. If I get pulled away from the bench, I will restart my last step. I always recheck my scales zero with check weights also.

Again, it happens, don't beat yourself up about it. Just a good heads up to make sure it doesn't happen again. I hate having to force a bolt open, so it really makes me pay attention to what I have going on. Scotty

 

[DrMike]

Catastrophic failure due to stress is almost always cumulative. This is not to say that destruction of a barrel/action does not happen after one incident, but the more common cause is cumulative setting the stage for one over pressure cartridge. A competent gunsmith can check to ensure there is no damage to the action, no bulging or visible cracks. You can do a few measurements on a case fired in the chamber to ensure that the chamber is not seriously affected. The velocity you report would indicate a pressure that was near the stress limit for brass; you were near 83 to 85 k psi. Consequently, that pressure with H4350 would be generated by as little as four grains overcharge. Modern metals used in manufacture of rifles will tolerate more than 160 k psi. One incident likely did no permanent damage. An inspection by a gunsmith would be for your own peace of mind. When these events have happened for me, I like to work backwards through the process to see if I can determine and eliminate the cause. I'm curious to know what the other cartridges you loaded at the same time did when fired. I wonder if you somehow had a contaminant that got into the cartridge, or even if the bullet was the wrong size. I have had (without naming the company) on several occasions boxes that contained the wrong bullets. Fortunately, in my case, they were smaller than the listed size. However, such mistakes are a two-way street.

 

[Antelope_Sniper]

I had to beat the bolt with the palm of my hand to get the bolt to open, the case head expanded so much that the case did not eject because the case rim was getting caught up on the "extractor" (the protrusion on the sidewall of the boltface) - had to pull the case off. Once I got it off, the primer fell out of the primer pocket. Very clear "ejector" mark observed on case head.

That's not very hot.
When you have to opent the bolt with a 2x4 and a hammer, and beat the case on the shooting bench until it finally dislodges from the bolt face, then you've shot a hot load.

When you have to send your Reminton 700 back to Remington to cut the case out of your chamber with a laser, that's a hot load (a realitive, not me, his scale was off 10 grains)

Guns can handle more then you think. It's when you feed them a steady diet of hot loads that fatigue set in, and you can have a problem.

 

[sithlord6512]

Thanks guys, the reasurances/experiences are reassuring. For more clarification, the case never got stuck in the chamber - with exception of the case not being ejected from the bolt face extraction seemed relatively normal once I was able to get the bolt handle up (note - case "wanted" to eject, but the the rim was caught up on the extractor - I had to gently pry it loose). I don't know if the primer was pierced - I was to distracted to look of it after I freed/pried my case from the extractor (the primer definitly popped out and fell to the ground).

I've since looked at my bolt-face more closely - cleaned the soot off and discovered a small arc/circularly-shaped "scratch" - about 2-3 mm long - the edges of the scratch are sharp/distinct (not etched? - hard to imagine that it was caused by slight melting of thebolt face?). Also, the ejector looks like it got a very small chunk scratched off - its once unblemished circular face now has a small "scar" on it. However, it seems to be functioning fine - it still ejects spent cases exactly as it did before by hot load.

To be honest, I think it will take me a bit of time to get over this psychologically. For the next little while, I imagine I will feel like those "bomb disposal" experts seem to feel in the movies when they need to disarm the bomb before the timer runs out (i.e., nerve-wracked - "which wire do I need to cut - is it the white or the red").

Thanks again for you constructive input/support - reaffirms my judgment that this is the best shooting forum - especially relative newbies like myself.

Antelope_sniper - Just recieved your post. Thanks - that is very reasurring - certainly reduces my anxiety.

 

[SJB358]

Your doing fine buddy. Awareness to your loading is where it is at and even then, some rifles just take more pressure than others and give off different signs. The WSM's and Ackleys seem to be a little tougher to see signs, but cycling the guns and primer pockets will show you a bunch. Don't get too psyched out. If you have good processes, there is nothing to be extremely wary about. Scotty

 

[DrMike]

its once unblemished circular face now has a small "scar" on it.

A mere beauty mark. Consequently, it is always the "green" wire (or was that the "red" wire).

 

[Guest]

Just be glad you're not colorblind.

Mike - what do you think caused the beauty mark? I'm only concerned if it was erosion around the primer pocket - which would make a semi-circular scar, but look etched not scratched. Hmmmmm...seems like brass would be too soft to scratch steel? Any ideas?

 

[DrMike]

It would be impossible to say now. Two thoughts occur to me. One is debris adhering to the base of the cartridge, which if the debris was sufficiently intrusive could conceivably cause a pressure spike. I don't believe this to be the case, but without actually witnessing the "beauty mark," I can't rule it out. Alternatively, if the primer had a steel cup, the rearward force could have caused such a scar. Again, without seeing, it is impossible to speak definitively. Thus, I am only speculating.

 

[Ridge_Runner]

Just be glad you're not colorblind.

Mike - what do you think caused the beauty mark? I'm only concerned if it was erosion around the primer pocket - which would make a semi-circular scar, but look etched not scratched. Hmmmmm...seems like brass would be too soft to scratch steel? Any ideas?

my guess is hot gases escaping around the primer slightly flame cut the bolt face, your rifle will be ok.
RR

 

[Guest]

That's where I was going, RR, with regards to erosion around the primer pocket. Not sure how deep the "cut" is and how much that changes the hardness or durability of the bolt face. Maybe a mountain out of a molehill, though. I'm no metallurgist, and I didn't even stay in a Holiday Inn Express last night.

 

[OldMan]

Years ago I had a buddy with a .264 Mag, I made the mistake of telling him I shot 80 gr of H870 in my 7mm Mag. Well he figured it was the same case necked down. He broke the lug off one side of his Savage 110. That's a hot load!!!

 

[FOTIS]

You handload long enough you will see this at some point. :shock:

If you are that concern have it checked out by a competent smith. :wink:

 

[Desert Fox]

You're rifle is fine. I have the same thing happen with my 308 Winchester. I developed a very good load during winter using BLC-2 and 168 grain Nosler Comp. I believe it was 45 grain if I'm not mistaken. Took the rifle shooting one summer afternoon in August where the temperature was around 105. I had the ammo box setting in the bench for a while. It was in a shade and not exposed to direct sunshine or anything so I figured it will be fine.

The first shot sounds funny but the case extracted okay and only showed a hint of high pressure. The second shot sounds the same but this time smoke was coming out at the rear of the bolt around the shroud area. The bolt froze and won't budge. I had to use the handle of my large screw driver as a hammer to drive the bolt out. The case was so swollen that I can't extricate it from the bolt either. I had to use a plier to pry the case out of the bolt. I never found the primer.

I was so concern about my rifle that I called Hodgdon powder as soon as I got home. Talked to their ballistician and was told that all ball powder are temperature sensitive and that extra care should be taken when developing load where extreme temperature change is expected. I then asked him how much pressure does he think my rifle was exposed to. He told me probably around 75,000 psi and that the rifle is fine.

 

[sithlord6512]

First Attempt at posting a pic. Hope the cliche "a picture is worth a thousand words" holds true. Not the "scar"/blemish on the ejector face and the circular scratch/etch at the "12-1" o'clock position on the bolt face.

http://s1125.photobucket.com/albums/l59 ... tFace2.jpg

 

[SJB358]

I think your good buddy. It is but a mere flesh wound! Scotty

 

[DrMike]

Fire at will, Gridley. You're good to go.

 

[Guest]

No worries, man! You're careful enough to be aware and I have no doubts about your safety.