I have a Rem 700 PSS in .308 with the standard 26” barrel.  Despite all the work done to it this is most inaccurate rifle that I have seen.  I’m talking about a 3 inch group at 50 yards.  The trigger has been redone, it has about a 4lb pull and barely moves.  The trigger breaks when you think about firing, you can’t even feel the trigger move.  So jerking the trigger really isn’t possible.  The action we bedded.  It has mid height Leupold rings and a Simmons 3x9x50 Deerfield scope on it.  The rings were aligned and slightly sanded to remove any stress on the scope.  The ammo wasn’t the best and I know I could improve slightly with better ammo but I’ve shot  1 ½ inch groups at 100 yards out of a similar rifle using this ammo.  

I took it out over the weekend and the shots when like this.  The first shot was 1inch high and 1 inch to the right.  The second shot was 1 inch to the left and half and inch low.  The third shot was touching the hole of the second shot.  Now I know that the first shot out of a cold barrel will be placed different than follow shots out of a warm barrel, but 2 ½ apart seems like a huge difference.  Shooting about 10 more shots most were between 1/2 an inch to 1 inch and from 1 to 2 inches to the left.  I did have one addition shot that ended up touching the holes made by the second and third shot.

Any ideas on what could be causing such a huge variation in shots?  I did not have a torque wrench when I tightened the action screws.  I also don’t know about the scope and mounts.   It all seems tight but it would seem that would be the only cause for such a huge variation in the group.  I borrowed a friends deer rifle with cheap scope and was able to place most shots with in an inch at 50 yards, so I know it’s not just me be a totally horrible shot.

First, go buy a box of 168gr match ammo. Second, clean the barrel thourghly. Third, get that scope off of there and try a known good leupold, borrow it from a friend if possible,  make sure the action screws are tight, also check your base's mounting screws, do all those things and let us know what kind of groups you are getting.

I'll bet you will get .75" or better.

Check the crown of the barrel. If there's a nick on it that will throw off the accuracy.

Also, go to different ammo. Different weight, different brand altogether.

Have another shooter try the rifle as well. He/she may notice the scope being loose or whatever that you've not noticed.

Good luck.

Check the action screws. They should be torqued to 65 lb if I remember.  Also check the barrel to make sure it is free floating down the stock. You could have a bad (mis-formed) stock.

Your ammo, is it 7.62 nato (mil surplus), head space on Nato is different from .308  What weight bullet?? You should be able to shoot 147 to 175 gr very well.

Did you buy it new??  Barrel could be gutted or it might be a bad barrel.  

Quoted: Check the action screws. They should be torqued to 65 lb if I remember.  Also check the barrel to make sure it is free floating down the stock. You could have a bad (mis-formed) stock. Your ammo, is it 7.62 nato (mil surplus), head space on Nato is different from .308  What weight bullet?? You should be able to shoot 147 to 175 gr very well. Did you buy it new??  Barrel could be gutted or it might be a bad barrel.

The ammo was military surplus Hirtenberger.  But like I said shooting an identical rifle with different scope I got a much better group.

I bought it new.  After the bedding was done I checked to make sure the barrel was free floating and it was.  I also went through the shoot one shot clean method for breaking it in.  I did that the first 10 rounds.  Then it was shoot 3 and clean for the next 100.

The crown looks fine and the barrel looks good.

I have the action screws tight but I didn't have a torque wrench so I could put them at 65lbs.

Could a bad bedding job be part of the problem?

I will try using good .308 ammo the next time I'm out and seeing what that does.  I don't have any funds to replace anything else on it but next I will change out the scope and the mounts.

Scope could be shifting zero, which is a feature that you don't have to pay to get.  You have to pay to eliminate it. {i.e. Get a quality piece of glass}

You could also have loose mounts for the scope, if the gun is high and right one shot and high and left the next with no adjustments I would suspect the scope first.

Is the recoil lug in contact with the notch in stock properly?  Are the screws at 65 in/lbs?

Crown?  Perfect condition?

Clean barrel?

Quoted: It has ......a Simmons 3x9x50 Deerfield scope on it.

Considering your other info on the rifle, this would be my primary suspect, and get some match ammo.

I got a hell of a deal on a Browning ABolt shotgun that wouldn't "shoot worth a damn," according to the owner. That WAS true, until I dumped the cheap Trashco scope that came with it and replaced it with a Leupold. I figured the chinese-made trashco was the culprit, and was proven correct.

Quoted: and a Simmons 3x9x50 Deerfield scope on it.

 This would be first on my list also.

Ammo could easily be causing that much of a deviation.  It could either be a bad batch or your rifle may just not like it.  

I have a Savage 10FP-LE2 and it absolutely would not shoot Winchester 150 grain.  I thought I had something wrong with my scope mount or the rifle.  But someone gave me a few rounds of Federal Match ammo and the groups tightened right up.

The first thing I would do is change ammo - this is the cheapest and easiest solution.  If that doesn't work, then check to rifle or scope.

If you don't want to spend the money for a good inch/lb torque wrench, just go down to Sears and buy the Craftsman one (around $80 for the good ones).  Then take it back after you get your stock bolted in at 65 in/lbs.  The torque of the stock is important.

And, like the others have said, I would really look into some better ammo and scope.  You can sometimes get good deals on used Leupolds on ebay and such.  They have a lifetime guarantee, so no worries about it being used and abused.