Rifle problem with groups

[luke5678]

Hello, I am about 1 year into long range shooting. I have a remington sendero in 7mm Mag with a nightforce scope. The first year of owning my sendero it shot .5 inch groups on a clean bore (first dozen shots all together) then as barrel fouled they spread to about a inch at 100 yards.

Now (a year later) all of a sudden my groups are drifting about 1.5 inches left to right. The first shot on clean bore is 1 inch right. Then second is about 1 inch left of target. Then following shots drift about .5 inch right and stay there for about 10 shots. My elevation of shot is always perfect but now my groups drift on the windage.

I could really use some intelligent advice on what has happened. Did the barrel just change? I am not shooting on a hot barrel. Wait for it to cool each time and have exact reloads that have not changed.

I have duplicated this three times now at different settings/shootings so I know it's not me. I just don't know what the problem is or what could have changed.

[Shooter98]

Originally Posted by luke5678

Hello, I am about 1 year into long range shooting. I have a remington sendero in 7mm Mag with a nightforce scope. The first year of owning my sendero it shot .5 inch groups on a clean bore (first dozen shots all together) then as barrel fouled they spread to about a inch at 100 yards.

Now (a year later) all of a sudden my groups are drifting about 1.5 inches left to right. The first shot on clean bore is 1 inch right. Then second is about 1 inch left of target. Then following shots drift about .5 inch right and stay there for about 10 shots. My elevation of shot is always perfect but now my groups drift on the windage.

I could really use some intelligent advice on what has happened. Did the barrel just change? I am not shooting on a hot barrel. Wait for it to cool each time and have exact reloads that have not changed.

I have duplicated this three times now at different settings/shootings so I know it's not me. I just don't know what the problem is or what could have changed.

What works for me in those situations is the KISS method (keep. it. simple. silly.)

I usually start at the optics. Is the rings still tight on the mount, is the mount still tight on the rifle? Then I move to loads. Am I using the same exact load that the scope is zero'd on. Next is the stock and barrel. Is the stock touching the barrel now in any way it wasn't before. Is the barrel still tight and not shifted in anyway. Usually by now I've found my culprit. Only once has it been a scope failure as usually it's something alot more simple like loose base mounts.

[rscott5028]

I agree with Shooter98. Don't overlook the obvious.

- loose bases or anything about the scope that may be loose
- properly torqued stock/action screws
- anything touching the barrel
(my sendero had the fore sling swivel stud rubbing the barrel)
- clean bolt and trigger mechanisms
- changes in ammunition or shooting conditions (have a buddy shoot the rifle)
- does it have a muzzle brake and does the problem persist with/without the brake
- are your bolt lugs gauling

What's your cleaning procedure?
Do you...
- use a bore guide and run your rod only from the breach end
- use a carbon fiber or non-abrasive/plastic coated rod
- bronze brushes (never stainless... especially on stainless barrels)
- powder solvent
- copper solvent
- lubrication

Hope this helps!
Richard

[rscott5028]

The first shot on clean bore is 1 inch right. Then second is about 1 inch left of target. Then following shots drift about .5 inch right and stay there for about 10 shots.

If you disregard the 1st 2 shots from a clean bore, how tight is the group for the next 5?

[roninflag]

what they said. plus horizontal is usually the wind. of course with a the high bc of the 7mm you should have very little.

[bandit10-4]

I agree, Id start with the action screws, remove barreled action, see if anything is touching, and put it back in the stock and tighten screws to specs. Best thing to do would be send it to Shawn Carlock (Defensive Edge) and have him work his magic on it, I bet that would do it... Good luck and Good shootin to ya partner!

[Long Trang]

I agree with what was already stated. Check the action screws and anything touching the action/bedding. Rscott brought up something very interesting and I hope it does not apply. Check your bolt lugs to make sure they haven't gauled.

Another possibility is if you've had any work done on the rifle lately. After having my target rifle for a year, I noticed accuracy diminishing, like yours. After investigating the problem, I discovered I needed a pillar bed job done. Once I had it done, I keep the action screws torqued to a specific value each time I go shoot and I now sport 1/4 moa accuracy.

Good luck.