A Puzzling occurence

[Flip]

Over the weekend myself, brother and mate got out on the foxes.

Now after a number of shots my brother rem 700 17 Rem on one particular did not feel quite right and sounded a little different to him a miss was recorded. The bolt lift and extraction was only very slightly heavier than normal acording to him.

On opening the bolt he found that the case was stuck in the bolt face, the shoulder of the case was rounded/ blown forward and there was a large long half round dent / gouge in the case wall that extends back from the shoulder about 15 mm.

it took quite a bit to pull the case out of the extractor and bolt face and on doing so the primer fell out and it was observed that the case head had expanded quite a bit.

the rifle was thoroughly checked no problems were found. the subsequent shot were all fine with no problems apart from the bolt now is unreliable with extraction, so it seems the rem type extractor as been damaged.

I reload for this rifle and weigh every charge, I prepped the new rem brass myself all was checked and trimmed to the same length. I junked four cases out of the hundred new as they were rather shitty with large cracks or folds in the neck shoulder area.

It did not appear to be an over load but nothing is impossible I am very careful with my reloading and i know this rifle is very sensitive to charge weights as I have pierced a primer during load development.

The strange thing to me was the rounded shoulder. it appears to me as if this was a head space problem possibly. Is it possible that if the bolt handle is not completely down that it caused this problem as in an out of battery firing as the bolt drops when the trigger is pulled.

I will attempt to post some pics of the case

Flip

[Camel]

Now that's a strange one mate, could it possibly be an under load, no powder, but I don't know if the primer would be enough to push the projectile all the way down the barrel. Scratches head.
The dent could have possibly come from extraction, but its not likely.
One thing, what do you mean by the shoulder being rounded/blown forward ? Was it new brass you were fireforming or forming from something else, I am confused.

[Flip]

Sorry Camel,

What i meant to say was that the shoulder is now rounded out slightly not a straight angle as with a regular case.

could be an under load but it sounded normal to me. was not a squib or primer only.

not fire forming. brass was brand new first loading.

I'm trying to get some picks atm.

Flip

[Flip]

Righto the problem case is on the left. good fired case on right

[trevort]

watching with interest. If the extractor is damaged I guess you are off to the gunsmith and taking that case with you. Something dangerously not right there

[220]

Would it be possible for escaping gas from the enlarged primer pocket to get around the case and collapse the shoulder?

[Flip]

At first I thought possible to much oil in the chamber but the rifle had fired shots previously and then another 3 after that with no trouble.

the dent could have been made from escaping gasses maybe ?

I have measured the case ant it is now shorter that the others by .21 mm now.

Flip

[MISSED]

I was thinking a similar thing 220 but was more along the lines of the case not expanding to seal the chamber.

Was this the problem Uncle Nick had with his 257 WSM wildcat he was playing with.?

Lots of thoughts rolling around my head about this one.

[Flip]

Speaking of uncle Nick, that's how I pierced the primer. I stupidly took the starting load from his manual only and did not cross reference it. any way the Starting load was 22.5 in his book and 22 on the Adi site. .

Any way cheers fellas. Its got to be somthing. will get to the bottom of it.

Flip

[220]

I was thinking a similar thing 220 but was more along the lines of the case not expanding to seal the chamber.

Thought did cross my mind as well, I have seen similar shoulders from exactly what your talking about but never on a case that shows signs of way to much pressure at the case head.

Somehow enough over pressure to expand the case head and primer pocket creating a situation where there is more pressure outside the case than inside it collapsing the shoulder.
Remington still make a big deal of their 3 rings of steel, maybe in this case it is totally sealed not letting escaping cases go anywhere but out the barrel.

[Camel]

Congratulations Flip, you have found something that I haven't heard of in all the 40 odd years of shooting and 30 odd reloading, that is a real puzzler alright, I cant for the life of me think what could do that, the dent doesn't look like it has hit anything, to me it looks like its been sucked in on itself, not a Remington is it, I have heard they suck.

Sorry couldn't resist that one.

Ive had pierced primers before, but I don't think the gas would go forward, if it was caused by excessive pressure I would presume that the shoulder would be blown out nice and sharp. I cant help but come back to a squib load, which powder are you using, could you give us your complete load data.

sorry mate not much help, but at least no one was hurt and if the only thing wrong is your extractor, then you got away pretty lightly.

[Flip]

Yeah cheers camel. Every one was safe and well.No stress every bit helps.

No gasses were observed exiting the gas ports and my brother felt nothing on his face as I did when I popped the primer. I also heard the primer go but this shot sounded normal shot to me as I was sitting next to him.

It did seem to land short a little but not much.


Rem brass: first loading from new and prepping
Primer: Rem 17 1/2
Powder: AR2208 22.1 grn
Projectile: Hornady 25 grn HP.

Cases were ran through a full length die then all trimmed to the same length, primer pockets uniformed and flash holes deburred.

All cases in this batch (50) were loaded at the same time, I used the yellow Lee dipping scoops in to the pan of a Redding balance beam scale set up on its own shelf at eye height to weigh each charge. All cases are ket in a MTM case.

Some time things happen I know. I have a factory 204 Ruger case with very strange looking primer after firing.

Cheers a gain

Flip

[CZ550]

Flip,

Never seen anything like it and I might be barking up the wrong tree here, but could it be possible that the case was already shorter than than the FL resized length from factory? You have said that it is .21mm shorter, perhaps it already was already shorter prior to reloading it. Too much head space, BOOM, shoulder swells to fit extra space, sucks brass from rear of case to fill the space?

As I said probably wrong, but very interested to know what caused this!

Regards,

CZ550

[Flip]

Quite possible CZ550.

I don't think your barking up the wrong tree at all. I checked the over all length of every case but not the shoulder location relative to the neck is it possible that the case was not properly formed and the shoulder was to far back to begin with. Would this explain the apparent head space issue??

There is a slight polished ring around the neck about one third up from the shoulder.

It is certainly strange. I've not been reloading all that long so I figure a lot of you folk have much more experience than I and may be able draw some light on it and I thank you all for your input


Cheers

Flip

[kickinback]

Tell me about the shot fired before this one.