Help! 7mm Stw

onlybears

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I've been loading for my Sako TRG-S M995 in 7mm STW, 26" 9.5 twist barrel. I've tried 120 and 150 gr. Barnes, 150 gr. sciroccos, and 168 gr. smks; in front of h1000, 7828, 4831, and rl22. I have yet to get under 1" vertical variation. I have tried everything in my sleeves. So before I spend a couple grand to re barrel is there any ideas on what I may be doing wrong? I've loaded coal from recommended minimum to max that fits in the mag but in my experience Barnes liked to be jumped so I can't imagine that to be the problem. And no I have not scoped the barrel. Has around 500 rounds. Any info even criticism is more than welcome.
 

MALLARD

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Re: Help! 7mm Stw

try COAL's that are longer then your mag length , determine where the lands are and work backwards from there. If you a determined to feed from the mag , well , 1 inch isnt that bad is it ?

i assume you can shoot less then an inch fairly consistently with a different gun right ?

what kind of glass are you using ?

how much horizontal spread are you getting ?
 

Clark

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Jul 4, 2003
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Re: Help! 7mm Stw

onlybears,
Accuracy is a product of many variables.
I have zillions of beater center fire rifles and two nice ones. I go through a check list for accuracy, both for the junk I drag to the range, and others I help there.
1) Test rifles in 6 mph or less wind or test at 50 yards.
2) Use a 10X or more expensive scope or a 14X or more cheap scope.
3) Spend two hours and ruin several bronze brushes getting the Copper out. The brush does no good if the bristles measure less than the groove diameter. Brushes can wear out in 10 strokes and become hand me downs to smaller calibers. You may only get 10 shots before you are Copper fouled again, and the first shot is a fouling shot. So have the rifle sighted in when you clean it. Look into the muzzle at a 45 degree angle, and rotate the rifle. You should be able to see the last 1/4" of lands and grooves. The Copper may appear a Gold color or a red color. You must scrub until all Copper is gone.
4) Most rifles get the best group at 50y or 100y with a reduced load with faster powder and light weight Vmax bullets seated long.
5) Don't use an expander ball. If a piece of brass has been resized and used an expander ball in the same step, it is now bent. The best way to get the neck straight again is to fire the brass again. We don't like bent necks because that makes the rear end of the bullet not concentric with the bore.
6) Seat the bullet long. Half way between touching the lands and getting stuck in the lands. If the front end of the bullet is jammed into the lands, at least ONE end of the bullet is concentric with the bore.
7) Practice dry firing on the bench until the cross hairs stay on the bullseye. Adjust bags, benchrest, posture, or whatever it takes.
8) Float the barrel. Use a dollar bill to check that the barrel does not touch the stock from the end of the stock all the way back to within and inch of the receiver. Anything touches the barrel, sand, chisel, drill, or file it out of there.
9) Make sure the scope mounts [or bases as Brownells calls them] are tight to the receiver. Those screws commonly get loose. The ring screws never get loose. But very often bad groups are caused by loose scope mount screws.
10) Make sure the action screws are tight. Hold the rifle with one hand on the rifle wrist and with the other palm, punch the barrel. The barrel and stock vibrating like a tuning fork sound should be a bongggggg. Not a buzzz. Not a bump. The under damped exponential decay of a sinusoid indicates a stiff connection. We need it stiff to make the stock mass count as part of and a consistent part of the recoil reaction before bullet escapement.


Mallard, when you get back from Mcdonald's try a new load in your 25acp: work up to 5.5 gr Power Pistol, 50 gr FMJ, .9" OAL. Expect loose primer pockets at 6.0 gr. That is a quad triple load of powder, and the recoil stings. Compare the penetration into wood vs factory ammo.
 

onlybears

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Re: Help! 7mm Stw

I'm using a Nikon monarch 4x16x42sf w/ mil-dot reticle, leupold rings connect to integrated rail. I've tried cleaning the barrel until there was "zero" fouling, and I've tried shooting it dirtier. It definitely likes to be clean. Ive shot prone off a bi-pod, off-hand, in a vise. And I don't think it's operator error. I get really upset when my .338 wm shoots over .25" and your absolutely right, an inch isn't bad. It's hard to eye-ball bears at 400m when your gun shoots an inch at best though. I've tested coal out to the lands and it still didn't give me much better. I did find a load that got down around a half inch, it was a 168 gr smk in front of 70 gr. of h1000. The only problem is it was going entirely too slow. I never shot it through a chrony but it had an 8 inch bullet drop from 100-200. I just wanted to make sure I wasn't missing anything. I'm pretty set on a 30" 8.5 twist tube cut for the 190
Matrixs to fix my accuracy issue though.
 

Busterstw

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Re: Help! 7mm Stw

I love the stw and have a Sako 75 that I have set the barrel back to shoot 168 Berger vlds done some trigger work and had it re crowned. It shoots two bullets well Barnes 160tsx flat base and the bergers. Both will consistently shoot less than 1/2 moa and as good as .2-.3s driven by RL25