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Discussion Starter · #1 ·
I've been shooting a Savage 116 in 7mm STW for 6 years now.
When I first brought it home it blew the primers of the first 2 shots, primers were stuck to the bolt face.
Sent it back to Savage, came back working but I always thought the primers were a little flat after firing.
I've shot a variety of types of ammo, all factory, main hunting load is Win. Super X, 150 PP.

Took it out yesterday, using the same box I hunted with last year with 6 rounds fired from it.
First 2 shots seemed fine, 3rd had a dark ring around the primer. Next 2 left the primer free in the action.
Ejector button was stuck in the bottom of the hole, this will be the second time I've replaced the spring.

This gun does not see a lot of ammo, I've got a cabinet full of other rifles that don't kick like this one and a couple of others that kick more.
It strictly fits the need for the 2 deer stands I have where I can reach out long ways and boy does it.

Can head space change just from shooting?
Do I have a bad batch of ammo? I've got other brands to try but want the head space issue resolved.

Thanks in advance, deer season for me will be the week of Thanksgiving.
 

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I would suspect hot loaded ammo. Try this check: Pull a bullet and dump the powder, chamber the primed brass and fire the primer. After you eject the round measure how high the primer has raised above the end of the cartridge, the primer will force it's way back against the bolt face from fireing and push the brass all the way into the chamber, you will be able to measure the headspace directly. Larry
 

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I had a similar issue. I found the primer pockets had enlarged. I had some brass that had been shot several times. I use a new primer in my calipers to check the pockets by loking it into the calipers then used the inside measure to check the pockets..
 

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The dark ring around the primer is leaking gas. The loose primers in the action is almost always caused by over pressure loads causing the primer pocket to enlarge releasing the primer as ejection occurs. Over pressure can be caused by several situations. An improper load is one but not often seen in factory ammo. A chamber that is out of spec is a real possibility and what I would check on first. Are there any bright spots on the case heads of fired cases? This can indicate brass flow into the ejector hole. Bottle necked belted cases have a fairly unique problem in that the head space is set from the front of the belt to the bolt face. But the case has a shoulder that will readily head space the round. This fault usually manifests itself in case head separations and these are the usual result of excessive head space. Over pressure is very dangerous but can have several causes. I always hesitate to suggest it but a call to customer service is in order. The 7mmSTW seems to hae chamber problems a lot. I've seen more than one exhibiting high pressure signs with factory ammo. The usual culprit was a short throat.
 

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Discussion Starter · #5 ·
Thanks guys for the replies.

Gunnut, no real shiny spot where the ejector sits on the case head but very dark around the spot from the leaked gasses.
I plan on giving a call to a couple of local smiths to see if they can measure and tweek the chamber.

Larry, I'll have to give that experiment a try just out of curiousity.
 

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My 7MM STW is a 700 Remington with a 26-inch Shilen stainless barrel which was installed and chambered by Shilen. It gives full, maximum load velocity with what should be less than maximum powder charge handloads. I guess it probably has a tight chamber and the throat was cut for a small jump with the specific bullet I use. (Tight chambers and short bullet jump both increase pressure and velocity.) If one did not work up loads for that rifle with the aid of a chronograph he probably would have worked up to what was listed as less than a maximum load and wondered why the primers blew. Anyway, if a chronograph shows too high of a velocity the gun would also have too much pressure. Nothing is free. If so, handloading could solve the excess velocity/pressure problem by using a smaller powder charge. Chronographs are worth having. Another factor could be barrel temperature. Any time I shoot a series of shots where the barrel is warming up and am using my chronograph, the velocity is greater with each shot. For most powders, higher temperatures cause higher pressures and higher velocity. I have been handloading for over 40 years but was surprised during a moose hunt a few years ago. I worked up hot loads for my .338-.378 Weatherby. While doing this I did not let the barrel get hot. That is, I let it cool down between each shot. I always figure there is no good reason to let a good barrel get hot, except maybe for prairie dog shooting. During the moose hunt I shot a moose and my guide could see the bullet hit the lungs. It just stood there like nothing happened and I would have just waited until it dropped. But my guide told me to shoot again, so I did and again hit the lungs. I did not notice any difficulty extracting the first cartridge but the second one was difficult to extract. The moose continued to stand there and my guide told me to shoot again and this time the moose dropped, and I could only get the third cartridge extracted with a great deal of difficulty. Each time I shot, the barrel got warmer, and velocity and pressure would have increased. In addition it was raining all the time and I was hunting with an emty chamber and a loaded magazine. The cartridges were wet, so the water adhearing to them would have taken up any space between the cartridges and chamber, in effect producing a tighter chamber than I had when working up the load. Anyway, I would guess the barrel on your rifle was warmer during the 4th and 5th shoots than during the previous ones.
 

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Have the head space checked. if it is not right have it adjusted Savages are easy to do. If it checks out right then then suspect a cartridge problem. We have seen factory loads that are hot. And we have seen factory cases that where not to spec causing an excessive headspace issue.
 

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Discussion Starter · #8 ·
Thanks again guys.
Having talked to 2 different smiths and a long time reloader, all 3 came to the same conclusion that it is a bad batch of ammo.
None of them could see the head space changing in the 6 years I've owned and shot it, unless some how the barrel nut came loose.
No barrel rotation can be visually detected and both smiths agree that the torque specs are such that the odds of it coming loose are astronomical.
They all suggest to take a shot with another brand of ammo and inspect the case.

Also I always allow the barrel to cool between 2 shot groups.
Gives me time to shoot the other rifles.
 

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Because it is factory ammo and not reloads I will keep most of my comments to myself.

But one thing that we found is that a less than minimum load will develop higher chamber pressures than a load - reloaded near max.

Also, if a round is reloaded and it came from the factory with a slight crimp in the primer area. The new primers will not fit without a crimp being applied.

Some primer crimpers cost as much as a whole reloading outfit.

I would just change brands of ammo and see if it made a difference.
 

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If the belt is 'short' [less than .220] and the chamber shoulder is on the deep side..........you could have a head space problem.

Check the belt length, then measure the length of a fired case, compared to the new ones. [ I use a drill bushing, that the case neck will fit into and the shoulder seats against, and measure the over all length of bushing and case]
 

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Discussion Starter · #11 ·
Update.
Emailed Winchester on Tuesday, got a personal reply Wednesday morning.
Talked to the gal at Winchester, no recall on that ammo but she issued a UPS call tag for all Winchester ammo I have.
UPS picked up my 4 boxes Thursday.
I thought that was a fair and timely response.
And she wanted me to include an invoice for the ruined ejector. I told her that it's ok I'll fix it myself, 5.00 in parts.

Fired some Remington ammo tonight, standard 140 gr. core loks, no high pressure signs at all, not even the flatten primers I always got from the
Winchester load.
Thank goodness the gun's ok, tweek the scope this weekend, look out whitetails here I come.

Thanks for all the info and suggestions.
 

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Discussion Starter · #12 ·
Update.
Winchester hasn't said anything about the ammo but they sent a bunch of gift certificates.
I feel a little bit like they are buying me off but I'll live with it.
They sent $240.00 worth of certificates for 4 boxes of ammo that was worth $130.00.
Not bad customer service, good communications and fast action.
Still curious about the ammo if there was an issue with it.
 
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