rifle trouble diagnostic help please!

[Runningwater]

I live in the Denver area, and last time I was "home" (NW Nebraska), I dropped off my rifle (Kimber 8400 300WSM) for him to make sure it was on zero (he has a lot more time, space, lead sled, etc). I had just shot it earlier that day and it seemed pretty on, but perhaps needed a couple clicks left - but was from off the top of a fence post shooting, so not precise. He calls me and he can't get it to even hit paper consistently at 100 yards. He's checked the rings and they are tight, and he's cleaned the gun. My thought is something that sudden and catastrophic is most likely the a scope failure? Maybe the mount/base? its a windage ajustable Leupold base - which I was suspicious about, but he says the scope seems very secure to the gun, and if its not even on paper at 100 it seems like you would notice some play. He says on the first shots of groups the first shot may be 6 inches high or 6 inches low - just all over the place? The rifle has a history of being a very good shooter - the same friend has played with it several times before over the years and says its one of the most accurate guns he's ever shot.

So maybe the extra stress from being shot in the lead sled caused a scope failure? Its an old Burris fullfield 3x9. Ideas? Thanks! Dan

 

[rileybassman]

Is your friend a good shot? That's the first place I would start - assuming since you shot it well that he would (no insult intended)... but lightweight rigs are harder to shoot accurate.

First always check the bases - I've had the leupolds creep even when they seem tight.. I won't use them anymore - use one piece, talley etc.

If it has shot good in the past I highly doubt it's the gun... swap bases and test, then scope and test and I bet you will find it.

If it's truly the rifle, check for action torque specs and magazine binding - those two are easy.... then muzzle crown etc...

 

[Runningwater]

No offense taken - he is a good shot, a very good shot who does much more shooting than I, and he is experienced with this particular rifle. That's why I usually have him do my "fine tuning". We'll check/replace the bases first and see where we go from there. I've been getting the wandering eye to put a nicer scope on it for awhile now, perhaps this will be my excuse.

 

[LaHunter]

I would suspect scope / mounting issues. Those Led Sleds can result in more stress on your rifle / scope

 

[Gunnersdad49]

I always look for the simplest answers first.

Is he using one batch of ammo? Is it the same type that you normally use? Handloads or factory? I would rule out the ammo factor.

Next, action screw torque (assuming optics and mounts are torqued already).

 

[Runningwater]

same factory ammo it is usually eats - actually we started with the same 1/2 box from the last time we checked it. We do plan to check the action screw torque. According to Kimber, 65lb front and back, going a little bit at a time front and back. Thanks - will let you know what we find out.

 

[Stid2677]

Have a sheep partner that recently had similar symptoms with his Kimber Montana, the smith discovered the forward action screw was bottoming out into the action and not applying correct torque between the stock and action.

 

[ckleeves]

I would suspect scope / mounting issues. Those Led Sleds can result in more stress on your rifle / scope

X2. I would pull the scope, double check the rings/bases, mount another proven scope and try again.

 

[Runningwater]

As a follow up for anyone that was curious - it was the scope. Put a spare 40 year old Bushnell Sportview (or something like that) on it and she's back to sub MOA. Something internal on the Burris must have broke loose in the lead sled. Its obvious that those put more stress on things (stocks, mounts, optics), but I'm a bit disappointed in the scope. So have a new scope on the way. While I'm at it I'm going to put on some LW Talley ring/mount and drop about a 1/4 lb. Now to continue getting in shape to put in in use the end of September!

 

[LaHunter]

Good to hear you figured it out. Good luck on your upcoming hunt.