7mm STW problems...........need your input.

[MtnOak]

I purchased a used savage model 114 7mm stw pre accutrigger in pristine condition, gun is beautiful, started off with nosler trophy grade accubond 160gr (red box), and right out of the gate prolly 4th shot blew a primer and noticed the ejector spring had broken and kept the pin stuck out, so put a new spring kit in and start shooting again and had a hard time getting any kind of group, so I changed rings from vortex aluminum rings to steel W.A.R.N.E. rings (scope is a vortex viper 6.5-20x50) and started over, just as it seemed rifle was getting close to zero (+1.6 inches @100yds) I ran out of the older red box noslers and opened a new black box trophy grade accubond 160's (same ammo) first shot was 4 inches higher and couldn't open the bolt, when we did get it open the primer was blown out of the brass, same thing after 3 more shots, even tried another box of same ammo and same thing on the first shot, called Nosler they are swapping out the 160's for 140's thinking it will lower pressure and end the problem. I took the gun to a gunsmith and had head space checked, bolt checked any tolerance that needed checking and gun was fine, he fired 3 different ammo manufactures through the gun and it operated fine, so...Â…Â…...im thinking change brand, started shooting HSM 168gr berger VLD and the first shot right out of the gate was dead center +1.6 @ 100yds (hard to believe) then on the second shot it was 7 inches lower and 2 inches right, third shot was nearly bullseye 1 inch left, fourth shot was 2 inches high and 2 inches right (haven't turned a dial yet) I'm scratching my head at this point, just looking at the riflings they look fine as far as wear goes so now im thinking maybe this gun has been fired quite a bit before I got it and maybe copper fouled, I spent 3 hours tonight using bore cleaner and copper remover cleaning this thing and constantly got a black then green residue on patches for ever before I finally started getting clean patches, assuming the green was tarnished copper residue im starting over with the HSM ammo tomorrow if this doesn't tighten the group on this rifle what else can it be???? I know bedding the stock may help some but this rifle should at least shoot 1 1/2 no more than 2 inch groups at worst at 100yds...Â…Â…Â…..:frusty::noidea: Your thoughts????

[big honkin jeep]

That cartridge has a lot of juice. What kind of bench and rest are you using? Wouldn't take much to want to flinch.
Maybe the scope went south??
I have a couple of rifles that take a while to settle down after cleaning, so I dont know if you helped or hurt your situation by giving it a thorough cleaning.
Just a couple of thoughts.

[MtnOak]

I actually think I started getting a decent group at shots 7, 8 and 9 yesterday but ran out of time and nearly out of ammo, i'll update maybe this weekend when I have more.

Started on a led sled with the Noslers but now im using bags on my bench with the HSM ammo, as far as flinching this rifle has some push to it but not too bad, I've shot worse.

[Robinhood]

For pierced primers check your firing pin profile and protrusion. I would think .035 - 040 would be good enough. The pin should not have a sharp edge on it and should have a good radius. Also check the firing pin hole clearance.

[tobnpr]

7STW is a true hot-rod- maybe around 1000 rounds give or take depending on how hot it's run.
Got a bug up my ass- even though I don't hunt- because I'm a big fan of 7mm and want to push a 162 as fast as it'll go...and just bought a reamer to build myself one (but on a different action).

Since the smith was (I guess) only asked to do a "safety check", he didn't look further- but your issue could indeed be copper fouling to an eroded throat.
Buying a throat-burner with an unknown round count is a gamble without borescoping- and even then no guarantees.


Then there's the recoil...the 7STW is right there with the 7 ultra mag as one of the heaviest recoiling rounds for a typical sporting rifle, more than a .300 Win Mag.
Especially in a lightweight stock, many shooters will be unable to shoot it consistently after having been pounded by it a few times.

If you're experienced with heavy recoiling rifles in lightweight stocks and can shoot them accurately this may be a moot point- but otherwise, it's a valid "variable". If you have (or have access to) a shooting rest/lead sled, it'll tell you whether the issue is at least partly the shooter.

Good luck with it.

[deerhunter99]

I have never had one but my friend hunts with one, his seams to shot pretty good 1 1/2 groups !!!

[MtnOak]

So…..I know it’s been a while since I’ve been on here since starting this thread but I thought I’d update and planning on staying on here .
I sent the model 114 7mm stw to savage, they did some machine work in the chamber and polished it sent the gun back, I then had it glass bedded (not impressed with the bedding job) now I’m waiting on a new scope , after all this work and wait if I can’t get this gun to group she’s finding a new home or barrel…

[Dave Hoback]

I missed this whole thread of yours back from ‘18. But had I seen it, I’d have thought Savage would do work to the chamber. The blown primers & stuck case(bolt handle not coming up), are high pressure warning signs. Stout pressure signs at that. And on factory ammo no less. Sure sounds like it was a tight chamber to me. And that will affect accuracy as well. I’m wagering you will see a difference given the chamber work & bedding. Curious, you said you weren’t impressed with the bedding. If you understand good vs bad bedding via visual inspection, why not do it yourself? Don’t get me wrong; I’m not saying everyone need should be able to do this. Some just aren’t mechanically inclined or don’t have an area to work...some simply have no desire. I ask because typically, most like this don’t really know good from bad bedding. Unless you mean whoever did the work perhaps just left extra bedding epoxy material maybe a bit messy?

[MtnOak]

I missed this whole thread of yours back from ‘18. But had I seen it, I’d have thought Savage would do work to the chamber. The blown primers & stuck case(bolt handle not coming up), are high pressure warning signs. Stout pressure signs at that. And on factory ammo no less. Sure sounds like it was a tight chamber to me. And that will affect accuracy as well. I’m wagering you will see a difference given the chamber work & bedding. Curious, you said you weren’t impressed with the bedding. If you understand good vs bad bedding via visual inspection, why not do it yourself? Don’t get me wrong; I’m not saying everyone need should be able to do this. Some just aren’t mechanically inclined or don’t have an area to work...some simply have no desire. I ask because typically, most like this don’t really know good from bad bedding. Unless you mean whoever did the work perhaps just left extra bedding epoxy material maybe a bit messy?
it’s just messy, more than I like, the stock is very nice and when taken off it’s the first thing you notice, as long as it shoots good that’s all I’m concerned about really, I’m just hoping after all that’s been done to this rifle she starts to put consistent groups down range…..we are gonna see..
I’ve got 2 boxes of accubond 140’s, barrel has a 1/10 twist, I’d rather be shooting something in the 160’s for elk or moose but Nosler thinks the 140’s will group better with that twist rate..

[Dave Hoback]

Yes, messy bedding is unsightly, but doesn’t always tell the tale to its effectiveness. A good way to tell if your bedding is a decent job: does the Barreled Action seem to fit like the stock is a glove? Does the stock “cradle” the Action? And when placed in the stock even without the screws, is it seemingly impossible to slide forward of backward any? Those are hallmarks of good Bedding.

Yeah, 1:9 is IMHO, the most versatile twist. For the typical length of a 160gr BTHP pill, the 1:9 is ideal. Your 1:10 may stabilize them “ok”, but yes, you likely will see better accuracy with the 140, or perhaps 150gr.

[8mm RUM]

I have an 8mm RM, it's the same case at the 7mmSTW, 375 H7H.
I run it HOT 220 gr Sierra 3100 fps, and 200 Barnes at 3200 fps.
It was a used gun when I got it, I have had it for 3 years and I my self have shot over 1000 shells.
There is no sign of a barrel problem. In fact I Just shot this 3 shot group at 100 yards.
https://i.ibb.co/bLp8tHR/200-gr-Barnes-reloads-6-X-bench-100-yards.jpg

​I'm betting you have a scope problem, I did not notice did you bed the action?

[Dave Hoback]

Yes, he was just talking about bedding, how it was messy. And we were just discussing it in the end of his thread.

[MtnOak]

I’m not saying the scope isn’t a small part of the problem but when your losing primers from factory rounds then there’s issues with the chamber of the barrel or action/bolt problems.
yes gun is fully bedded…

[Dave Hoback]

No, you DEFINITELY had something else going on. Popping out primers, case sticking in chamber.. those are OVERPRESSURE problems. And absolutely will affect the accuracy of the subsequent shots fired. That has nothing to do with the scope.

[Robinhood]

Pierced primers is not always a presure issue. Often it is a firing pin hole clearance and/or a firing pin tip profile issue. It does seem like preasure is the issue, but check the firing pin and hole for a place for the cup to flow.

Also primers being popped out requires enough clearance to allow that to happen. Over "sized" brass comes to mind. Check with a go and no go. Rent them if you dont have them.

Are you hand loading? If so what is your recipe?

Recheck headspace.

[Dave Hoback]

Pierced primers is not always a presure issue. Often it is a firing pin hole clearance and/or a firing pin tip profile issue. It does seem like preasure is the issue, but check the firing pin and hole for a place for the cup to flow.

Also primers being popped out requires enough clearance to allow that to happen. Over "sized" brass comes to mind. Check with a go and no go. Rent them if you dont have them.

Are you hand loading? If so what is your recipe?

Recheck headspace.


Oh, absolutely you’re correct Robin. I was aware of that. I’m confused as to the OP’s initial post as to if the the Primers were PIERCED, or BLOWN OUT of the primer pocket. The way I read it, the Primer was BLOWN out of the brass, which I believe is pressure related. A PIERCED Primer is due to something with the firing pin/striker, just as you mentioned.

And there is the sticking case he had. DEFINITELY pressure related IMO. But could have been a one off bit of random weirdness I guess. Hopefully he gets to shoot shoot & lets us know if the work made a difference.

[MtnOak]

Primers were NOT pierced, they were blown out.

[Dave Hoback]

Ok, that’s what I thought. I have a feeling you’re gonna have a different shooter on your handsome next outing. Just a hunch.

[mnbogboy2]

Blown primers and hard lift are perfect examples of high pressure. Blown primers are often a product of loose pockets and repeated loads on loose pockets. Pocket seal is lost with loose pockets. Multiple firings on the loose pockets cut gas trace passages that eventually lead to blown primers.
If i read right this was factory ammo and loose pockets shouldnothave been an issue..the ejector problem is common with blown primers. I had a blown primer jam the ejector and I end up drilling it out. I've also had theextractor blown right out of the slot. Found all the parts at the bench and got everything back in place outside. That little ball is a bigger to find when you end up shaking it out of the Maxwell in the stock. The way I drop lose and launch small parts shouldn't be done away from my workshop. I rely on my ears to tell me which direction they fall. The stroke I had last winterhasaffected both my eyes and ears. As well as the use of my left hand. Pretty difficult to do everything with one hand. (Dave Hijack knows this).

[Dave Hoback]

You know it brother.:(

Hey, I hadn’t realized you had a stroke friend. Praise Father above He kept you here with us.(and more importantly your family)

Pardon the off-topic tangent.