Loose stock question regarding accuracy

D

dead bird

Inactive
How much does a loose stock affect accuracy, and what is considered a loose stock.
Very frustrating day at the range. Groups were all over the place on a rifle that usually shoots moa or better. I shot several groups at 100 yards and the groups were as big as 2". When I got home I checked scope mount, rings and stock mount screws. Scope mount and rings were fine. Stock screws were not loose, but I did get 1+ turn out of each one, without over tightening(is there a torque spec?). Is that considered loose, and if so is enough to affect accuracy?
Rifle in question is Steyr SSG69, 308 cal.
Normally I would write it off as a bad day at the range but after shooting poorly with this rifle, I shot three sub moa groups with my TC Encore in 270. I felt a little better after shooting that rifle well, but I am still frustrated with the Steyr.
All ammo is handloaded. 308 was new lapua brass(fl resize); IMR 3031(39.5gr); Sierra and Speer 168's. OAL 2.890" speer and 2.855" sierra(.005 under chamber length). Brass 2.004"
What are your thoughts?
 
If the screws were 1+ turns loose, then yes that could have an effect on accuracy. The real truth will be if it shoots better the next time you take it to the range now that you have tightened the screws...
 
Yes rotary mag. I like the rifle but I will like it much more when and if it shoots as it should. Going to the range today, but not before I try the torque process in the link from your post. I'll update with results later today. Thanks for the info.
 
I have a Savage in .325 (8mm) WSM that is a pain to keep the stock screws tight. I can tell when they start to loosen because the groups start to open up. I am cntemplating using the blue Loke-Tite on them, but am a bit aprehensive because I like to remove the stock for cleaning.
 
Dead Bird it's interesting you posted this, as last week end I had my 700VLS 223 at the range and it went crazy on me. This rifle will shoot sub 1/2" 10 shot groups and last week end it would not even come close to that. I got home and checked every thing, all were tight except front screw, about a 1/2 turn. Went out on Monday and it was back. I don't think I can count on one hand how many times this has happened over the last 45 plus years but it did.
 
Those were sniper rifles back in the day. The stocks are very susceptible to slight warpage due to temperature differentials which cause screws to loosen. It was made before synthetic stocks were perfected. They are excellent shooters as well.
 
Load Data Records

Different bullet lot number? I found a bad lot of bullets when it happened to me. After checking scope , rebedding it was bullets. Now i keep a log book with lot numbers of bullet, primer, brass, powder. If accuracy changes, i know where to start looking.
 
Another frustrating day. Torqued down stock, shot 14, 3 shot groups. Five grouped sub moa. The others were the same as the other day. Returned from the range and checked stock, scope base and actually changed the scope to see if a different scope will make a difference. Scope in question Springfield Armory 6-12 x 56 gov model. I've heard different opinions on this scope holding zero, that's why I am going to try a different scope.
 
I think you're on the right track. You've done the troubleshooting just as I would have, not much more you can do.

What puzzles me is that 1/3 of your groups shot the way you expected.

Normally, if you've got a wandering zero, it's gonna do it all the time.

This is why I suspect- but don't know how you could test for, or prove/disprove- that it's related to the action and/or barrel harmonics.

Did you take a business card and check the barrel for free-float after re-torquing the action?

If what yournodaisy says is true- stock warpage would not just loosen action screws- it could very possible induce stress points on the action, screwing up the harmonics.

Just like improperly bedding an action can actually induce stress into it, the same thing could happen from a stock that changes dimensionally. Now, this is just from "yours" comment, as I know nothing about the rifle or the composition of the stock.

I can't find any specifics online. What year is your rifle, and what is the stock material?
 
I have not checked barrel clearance with business card, but I will. The rifle was purchased used and it is a difficult rifle to find info on. I believe that it possibly could be 2004 era of Steyrs, based on the limited info I could find. It has a wood stock, and that has been the difficult part. I have not seen or heard of any Steyrs with wood. I have seen numbers that translate to date codes on other rifles, but my rifle has no such numbers. It was sold as a SSG match. If it turns out to be a stock warpage issue, what is the solution to that problem. I am just trying to think ahead, in case scope swap yeilds nothing.
 
Wood stock?

In my mind, this issue becomes a whole lot simpler.

You probably already know this...but wood stocks change dimensionally with variations in temperature and humidity. Just like wood door that "sticks" when it's raining or the humidity's high... This doesn't happen with composite stocks, which is why all high-end precision stocks are of that material (fiberglass, carbon fiber).

The fix is a simple one- bed the action. If there are not pillars currently installed, and you want maximum consistency, install pillars as well.

If you're competent with a Dremel, this is not a difficult project to DIY (I've done all my rifles myself). There is a TON of information online, including vids on youtube and Midway USA on the subject. Here is one to get you started down the information highway:

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1242746

Pillars may be a bit more involved because you have an uncommon rifle, and you might need to make them (or have them made) yourself.

Rather than take up time and bandwidth here, feel free to PM me if you're not familiar with the process and I'll be happy to help get you steered in that direction.
 
That very same thing happened to me a month or so ago. with a laminated 300wm. The rifle would always shoot 1" or less then I took it to the range after deer hunting and it grouped shotgun patterns, tightened the stock and it was fine.
 
Well here's where I am at today. I did the business card to check that there are no pressure points stock-barrel. The card slid without any restrictions, so I guess I can assume that the barrel is "free floating". I then removed the action mounting bolts and seperated stock from barrel. The trigger guard/magwell is one moulded peice of plastic. The action bolts pass through this plastic peice, then through the stock and thread into action. The two ears/tabs on magwell/trigger guard that the bolts pass through before entering the stock(one behind trigger guard and one in front of magwell) are both cracked. It seems to me that this would prevent proper torgue from being applied due to the crack in the plastic. It seems like that is alot to ask of a plastic peice to hold torque values that actually hold the action in place for optimum accuracy. It also seems to me that this is a pretty cheap way of designing a so called quality/accurate rifle.
Although I agree that wood swells and shrinks due to moisture and puts pressure on barrel, , I do not think that is the situation here due to recent lack of humidity due to time of year.
As I see it here are my options. I would like to know if this is an appropriate course of action.
Assuming that the action and barrel are within acceptable tolerances for the accuracy expected, I would consider a bedded fiberglass or composite stock and the addition of pillars.
 
McMillan makes a nice-looking tactical stock for the SSG-69. Not cheap, but you get what you pay for...

http://www.mcmfamily.com/mcmillan-stocks-pricing.php

Initially I thought you could bed it into your existing stock, but I'm not clear on the issue of the busted plastic that seems to be playing the role of pillars...

I'm sure you could contact Styer and get a replacement part for less than the five bills ++ the MCM is gonna set you back.

Pictures would be helpful.
 
The shooting results you describe seem to indicate that the action shifts in the stock during your shooting sessions. This indicates an issue with bedding and action screw tension. A well-bedded action simply does not do this. I am unfamiliar with this arm and do not know what kind of recoil lug it has or if the bottom of the action is round or flat, but it may be that a simple bedding of the lug area would cure the problem. If the lug is at the joining of the barrel and action, then about an inch behind and 2-3 inches in front to support the barrel may cure the problems. If the lug is in a different place, then you will need to bed there and also below the barrel-action junction. Glass bedding need not be scary if you follow directions so that you do not permanently glue your action to the stock. I use Acra-Glas Gel from Brownell's and this would be much cheaper than getting a high-end synthetic stock, which you could always do if the bedding job failed. My torque specifications for action screws is: As tight as I can turn them with a good Forster by hand. You will need to do something about the cracked screw holes in the bottom plastic.
 
I am working on posting pics today.
The recoil lug is at the rear of the action. I am contemplating the bedding job myself, as it would be a good learning experience. Any experience with Devcon?
I need to contact Steyr on Monday and see if there is a solution, or any improvements to the plastic trigger guard/magwell .
Hopefully pics coming soon.
 
Here are some pictures of what I have been trying to explain
 

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Well, that explains it...
No "fixing" that- you need replacement bottom "metal"..

There are certainly composites with the strength of steel (or more), that assembly clearly is not made from such a material.

No choice other than to source a replacement from Steyr, maybe if you're lucky they're made from a different material now.

Honestly, they should be ashamed to have made that assembly out of plastic for cripes sake...throw away rifles are made better in that dept.
 
I assume the barrel is clean and copper free? Fouled barrels is the #1 reason why rifles stop shooting well in my opinion.
 
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