Tikka Broken Bolt? Factory Ammo Blowup

[wind gypsy]

Looks like a bad piece of brass.

 

[Hoggetter]

Brass failure,
55,000 + PSI of force pushing bullet out the chamber but with the split case you had blow bye pressure pushing out at the bolt face.
Trash those parts and do a full bolt disassembly for inspection.

 

[SDHNTR]

Do you have calipers? How much expansion is happening at the case web, or just forward? Any other fired cases look odd in the same spot?

 

[DiabeticKripple]

You can see the ejector mark on the CH in Winchester on the brass. It’s faint but it’s there.

 

[Darryle]

Look at the cases in the Styrofoam, I see evidence of bulging, primers are flattened, regardless of how little or how much and there are ejector marks.

The nickel cases would probably contribute to the lack of heavy bolt lift, the nickel acts like a lubricant on the surface of the brass

How many of y'all would put your kids behind the rifle with that evidence?

Do what you want, but the first thing I would have done was contact Winchester and have them handle it or get their input and let them correct their mistake. That ammo in that rifle is a problem.

 

[kpk]

Odd place for a piece of brass to split. I've had them split at the shoulder but never that far down.

 

[JPeters218]

Do you have calipers? How much expansion is happening at the case web, or just forward? Any other fired cases look odd in the same spot?

No calipers. I’ll check the rest closely tho and report back

 

[peaches]

Contact Winchester then proceed accordingly. Tikka won't touch this issue as you modified the rifle and used a can. Good luck, glad you weren't hurt.

 

[Lytro]

You'll need to pick up an extractor kit to rebuild the bolt, but I definitely recommend taking a good look at your firing pin as well. Those spare parts kits can be tough to locate in stock sometimes. An LRI Tikka replacement bolt would be a good sub if you're in a time crunch and don't have another T3X you can borrow a bolt off of in the mean time. Only an extra $200 compared to rebuilding your bolt if you end up needing to replace the firing pin as well.

 

[JPeters218]

So I looked really closely at the pieces of fired brass seen in the photos. On 3/4 there is a line all the way around the case about 1/8” up from the bottom shoulder. On 2/3 with that line I cannot see any bulging at all. On 1 I might see just the ever so slightest bulge, but it’s so little that I’m not even sure. The pictures above are kind of deceiving. It’s not nearly what that one photo makes it look like.

Regardless I filled out the form on Winchester’s website and i’ll wait to hear back

 

[SDHNTR]

So I looked really closely at the pieces of fired brass seen in the photos. On 3/4 there is a line all the way around the case about 1/8” up from the bottom shoulder. On 2/3 with that line I cannot see any bulging at all. On 1 I might see just the ever so slightest bulge, but it’s so little that I’m not even sure. The pictures above are kind of deceiving. It’s not nearly what that one photo makes it look like.

Regardless I filled out the form on Winchester’s website and i’ll wait to hear back

Get you a paper clip and straighten it. Make a small 1/8” dogleg or hook on one end. Stick that bent end down inside the case and then draw up from the base, scratching along the inside of the case wall from the base up. Do you feel the wire catch or grab on any variation to the brass? The case head is joined to the case body about 1/4 -3/8” up from the base. When a case lets go and separates, this is often where it happens. The wire will feel that separation starting to come apart.

 

[TAArrowood]

I would say you have a bad piece of brass.. I have seen a few rounds of factory ammo that had longer than spec lengths.. Upon chambering the round the brass was forced into the throat which "pinched" the bullet and increased chamber pressure substantially and caused a case rupture or separation.. Not saying this with certainty, but it is a possibility...Looks like your bolt and lugs did exactly what they were designed to do.. Primer doesn't show excessive pressure.. You may have gotten a case with a defective split inside the case and invisible to inspection... Glad you didn't have any injury of significant damage to your TIKKA.. All the best..

 

[JPeters218]

Get you a paper clip and straighten it. Make a small 1/8” dogleg or hook on one end. Stick that bent end down inside the case and then draw up from the base, scratching along the inside of the case wall from the base up. Do you feel the wire catch or grab on any variation to the brass? The case head is joined to the case body about 1/4 -3/8” up from the base. When a case lets go and separates, this is often where it happens. The wire will feel that separation starting to come apart.

Just did this. They all felt good

 

[Bodie1331]

I’ve seen a factory Hornady cartridge flow into the ejector of a Remington 700 - weird base failure - they wouldn’t do anything for the shooter except offer a box of free ammo. The bolt required a rebuild.

 

[4th_point]

The 8th Shot total of it, 5th of the string, I got a big puff of gas back In my face. The case was stuck in the chamber, and the bolt looked to be missing some pieces.

Glad that you are OK! And thanks for sharing this experience.

Getting a face full of gas is not something to take lightly. I'm assuming that you had safety glasses on? Did they get peppered with particles?

I'm not a ballistics engineer or ballistician but that failure mode seems like a hoop stress failure and was obviously far enough back that it leaked into the action. Good that the extractor was captured in the action and not a projectile that injured someone!

If the failure was farther forward, it seems that the gasses are less likely to leak rearward.

I'm curious if any of the bullets in the remaining rounds are loose. I wouldn't monkey with them too much, as you will probably be sending them to Winchester as evidence, but can you rotate them relative to the case? Or even worse, can you move them fore and aft by hand?

The reason that I ask about the loose bullets is because I recall some Silvertips having that problem. Some with setback. I don't think that small amounts of setback are as dangerous as with handgun cartridges, but seem to recall some reports of pressure spikes if a rifle bullet drops really far into the case where the expanding gas gets way ahead of the bullet and the case doesn't seal properly. The combustion event is different in that scenario and different than just a large amount of bullet jump. But I am not an expert in that so take that information with a heap of salt.

The powder charge would limit the setback but factory ammo often seems to use faster powders that would allow the bullet to setback a bit.

Again, all just speculation on my part but maybe something to check?

If it were me, I would want to know the bullet diameters with the remaining rounds. Or at least an estimate. But you don't have calipers or micrometer?

 

[4th_point]

If it were me, I would want to know the bullet diameters with the remaining rounds. Or at least an estimate. But you don't have calipers or micrometer?

And maybe the first question would be what are the diameters of the cases near the failure area? Are they undersized and explain that hoop failure?

Or just bad material or structural defect? Or is it the chamber?

It's an interesting failure especially since the case failed near the case head which should have the most wall thickness.

Whatever the cause it's a good reminder that the brass gasket is often taken for granted and is actually a complicated interaction with the chamber! And when things go wrong, hopefully the action can handle it.

 

[JPeters218]

I don’t have calipers. I strictly shoot factory ammo so never had the need for them.

 

[JPeters218]

Little update. Winchester got ahold of me and is sending me a shipping label so they can’t test the ammo. They told me time feel free to take it to a gunsmith and get it looked at if I want, and to look into the pricing of a replacement parts kit. Then once they test the ammo they’ll get ahold of me again and go from there

 

[4th_point]

Little update. Winchester got ahold of me and is sending me a shipping label so they can’t test the ammo. They told me time feel free to take it to a gunsmith and get it looked at if I want, and to look into the pricing of a replacement parts kit. Then once they test the ammo they’ll get ahold of me again and go from there

That's great. Please let us know the outcome.

And did any of the bullets spin or move in the cases?

I'm also curious how your safety glasses fared. Did they get peppered with particles or just gas in your face?

 

[Mountainrancher]

Really hope Winchester makes it right sounds like this is a failure on them.