shot pattern problem

I just bought a swfa ss 10X42 riflescope and I am having trouble with my shot pattern a 3 shot group at 100 yards is about 6 inches from one shot to another.  I have talley rings and base on a winchester model 70 300 win mag any suggestions on how to tighten my grouping and how can you tell if the scope is malfunctioning eventhough I just put it on yesterday 

Did you shoot the gun prior to mounting the SS?  What groups did it print before?
If it is a brand new gun, did you break in the barrel?
Have you tried multiple kinds of ammo, different bullets at different velocities?
Are you certain the scope mounts are secure and torqued properly.
What is your trigger break?
Do you "flinch" in anticipation of the gun going off?

A 300WM can be a kicker, it might just be that you tense or flinch, or it could be something else.  Answering the questions above will be a start towards helping.

I had a similar problem with a Leupold 4x, but was totally remedied after reading John Barsness' article on scope mounting in the Dec 2008 American Rifleman. My problem was proper screw tightening torque on the rings. Too tight or too loose can each cause odd behavioral problems with the scope.

I have had the gun for about 2 years and I got it used.  The prior groups were less than an inch.  I have only used the 150 grain hornady sst but that is what I have always shot.  I think that I have the mounts secure I made sure they were tight before shooting.  I sight my guns in with a lead sled so it is kind of hard to be off that far and I know I dont flinch because I havent had any trouble in the past with that gun

This will be a process of elimination so a few questions will have to be answered.

my mounts shouldnt be bent already they are as new as the scope

If they are alloy mounts the very first shot with a 300Win can bend them. The next shot again and so on, hence the shift in impact. They only need to bent 2 thou of an inch.

I have the talley light weight scope mounts I dont know what they are made of it dosent say

I have Talleys on my 45-70 and only shoot very hot loads out of it.  Mine have never given me a problem by bending, they are very well built.  I am certain they have been used on lots harder kickers than a 45-70 or .300.

Did you torque them properly or just tighten them?  They only need 15 to 18 inlbs of torque,  that is not very much.  You can typically do that with a nutdriver and your thumb and forefinger.  That is on both mounting it to your action and the ring caps.

If you have them to tight it can really screw things up and even ruin the scope.  If it is to loose you should see movement in the scope sliding.

Once you eliminate any mount problems, then if it is still there I would put the scope on another proven rifle if possible and try it as well.  That will help you eliminate if it is a scope problem or not.

Edited by 8shots - October/16/2009 at 10:31

Does talley have any mounts made out of steel

A quote from John Barnsness.  http://www.opticstalk.com/forum_posts.asp?TID=15632&KW=Talley&PID=177600#177600

What Roy said--plus the Talley Lightweighst are also very strong. Some people don't accept this, because they are aluminum, but they were originally designed by Melvin Forbes for his New Ultra Light Arms rifles, which can generate quite a bit of recoil.   The LW's do not use bases. Instead the bottom half of the mount includes the bottom half of the ring, and screws directly onto the action. This bottom half is a solid block of high-grade aluminum, so ain't going anywhere.   When my wife got a .270 NULA in 1991, I mounted a 2-7x Bausch & Lomb in the mounts and it never changed point of impact over the next decade, until the scope itself went belly-up. This was on a .270 that weighed 6 pounds with scope. I have also used the NULA/Talley mounts extensively on various magnums from .300 Winchester up (and one of those was a NULA weighing 6-3/4 pounds with scope) and the only problems have been with scopes, not the mounts that held them.   Many people who shoot big-bore magnums (mostly for African hunting) like the Talley steel rings, because these come in a detachable model that allows the use of iron sights if desired. It is a probably the most popular detachable mount for the purpose, partly because unlike some other detachable mounts, the Talleys are machined rather than cast.

Based on Johns input and my personal experience with the Talleys I would say your talleys are just fine.

I have never used them, but their bases are of steel. The fixed rings also seems stronger then the lightweight:

If it is not the rings, then either the screws are loose, or the scope is faulty.

If it does end up being the rings causing your problems, Warne also make very strong rings and they are steel.  While i personally have only have them on a .357 mag rifle and an AR, they seem very very strong. 
http://swfa.com/Warne-Maxima-Permanent-Attach-1-Rings-C2378.aspx
http://swfa.com/Remington-C2357.aspx

jeez, thought this post was going to be on shotguns.

 I think Talley uses grades of aluminum that are probably stronger than most steels. They aren't your average box store pot metal junk. I doubt they bent under recoil, but I do think there's a strong possibility that they are too tight and may have stressed or even damaged the tube, as others have suggested. Loosen them, look for ring marks on thre tube and re-tighten to torque specs and try again

The Talley mounts are plenty strong.  If the receiver of the rifle isn't true, holes aren't drilled straight, etc, this could cause a misalignment between them that may pinch the scope or prevent the rings from tightening properly.  That (along with other simple mounting errors) is what I'd look for first.

Jon A wrote: The Talley mounts are plenty strong.  If the receiver of the rifle isn't true, holes aren't drilled straight, etc, this could cause a misalignment between them that may pinch the scope or prevent the rings from tightening properly.  That (along with other simple mounting errors) is what I'd look for first.

Its shooting true now Im holding a sub-one inch group again.  I looosened the rings and changed ammo and it is shooting fine now.  Thanks for all of your help I appreciate it.

Dammit, I hate being wrong!!!