groups have gone crazy

[mustfish]

I am shooting a 7mm Sendero. 168gr long range accubonds. Nightforce NXS scope with Nightforce hardware. When sighted in I was shooting 1/2" groups. I later removed my stock and installed a timney trigger. I torqued the stock screws to 60 inch pounds upon putting it all back together. Went to the range and now find that I can't shoot a good group and most are an erratic 1 3/4". I allow the barrel to cool between shoots. Stock is the factory stock with aluminum bedding blocks and floated barrel. What now? Any advice.

 

[bullfrog]

Check your scope mount bases. This has happened to me before when I didn't use thread locking compound (loctite). Check the torque of the scope ring screws also.

 

[mustfish]

Scope base and rings were put on with an inch pound torque wrench and loctited.

 

[ohiohunter]

Back your screws off and stand the gun on its but allowing the lug to make good contact then torque your screws down while the gun is in this position making sure the barrel rides the channel appropriately.

 

[mustfish]

Ok, I will try that. Thanks.

 

[Dosh]

Fish, perhaps you couls try backing the action screw torque off a few # at a time. Some respond to more or less torque quite quickly.

 

[FearNoWind]

... factory stock with aluminum bedding blocks and floated barrel. What now? Any advice.

How much "float" do you have? Sometimes the rifle shoots well with factory torque settings that don't pull the barrel down tight enough to generate conflicts between the barrel channel and the barrel. Then, when it's torqued just a little tighter, the clearance is taken up and the stock interferes with the barrel "free float".
Check your free float to make sure you've got plenty of clearance from barrel lug to front of the stock - more is better than less.

 

[mustfish]

I did what ohiohunter suggested and backed my torque off 5 inch pounds. Will see how that works next range day.

 

[ohiohunter]

I did what ohiohunter suggested and backed my torque off 5 inch pounds. Will see how that works next range day.

Re-assembling your rifle using gravity to seat the lug will help keep contact points consistent. I do this with all my rifles regardless of bedding.

 

[mustfish]

I checked my scope base and rings with inch pound driver and everything is ok. Barrel free float is great and before taking the rifle down for new trigger install I was killing targets past 500 yards. Now I'm shooting eratic 3" groups at 100 yards.

 

[cj518]

Another thing to check that has happened to me is the mag box was binding, it needs to have play when the action is assembled.

 

[Punisher]

the order you tighten the front and rear screws can make a difference. tighten the front first then the rear. the best thing to do is to epoxy bed, re-torque and then check. as cheap as epoxy bedding is, all rifle should come with it.

really, it sounds like it's mostly a torque issue. but epoxy bedding will make it easier in the future.