I have a glitch going with a rifle and hoping to get some advice. The rifle is a Rem 7mag, bedded in a McMillan swirly. Speed lock and Rifle Basix trigger set at 2.5 lbs. The history is the rifle is capable of great groups with several loads (at the present I'm working with 162 A max's and 162 ELD x's).

The trouble I'm having is that whether on a bi-pod with a rear bag, front rest and bags or bags alone the crosshair usually moves-generally up and to the right no matter how I position or hold the rifle (this is when dropping the pin on an empty chamber). As a result the groups will open up. Not always but more often than not.

I've checked the culprits I'm aware of like the bolt handle touching the stock, relieved the mag box to make sure there is no contact, the firing pin spring is straight and not dragging.

Any ideas of what may be the cause besides a loose nut behind the trigger?

What about recoil control via NPA?

Happens when dropping the pin on an empty chamber. Don't know what NPA means.

NPA = Natural point of aim.
How you need to be set up so as not to negatively influence the shot.

Missed the part about the empty chamber. NPA affects how you muscle the rifle onto target, as well as how the rifle bounces off your shoulder, and can cause poor follow-through.

What scope and scope mounts?

Make sure you are applying straight-to-the-rear pressure with your trigger finger.

NPA can cause that when dry firing.




Dave

I've had a scope or two where something came loose inside that acted like this. Probably a good idea to at least try a different (known good) scope, to eliminate that possibility.

It could certainly be trigger technique too, as implied above.

I doubt this is a scope or mount issue, this rifle has worn a bunch over time but the scope now is a NXS 5.5-22x50 in NF rings. Last set up was a Leupold 4.5-14x42 with M1's in Talley lw's. I paid a lot of attention to finger position, stock pressure, etc. Doesn't happen with other rigs-even the very light ones. Someone mentioned bolt timing, and I was curious if it could somehow be related to the trigger. I have trouble breaking this trigger but it scales at 2.5 lbs.

The rifle wants to shoot, this is the set up


100yds with ELD X's


200yds with A max's

your comment about having trouble breaking the trigger, and thats not related to weight, IE I had trouble with a 8 oz two stage once....

Would lead me to think you are developing muscle tension while waiting on it to break.

one solution, to shoot IE dry fire faster, don't take as much time and see if anything changes.

NPA can damn sure affect dry firing bounce.

Thank you for the input rost495. That makes sense-the biggest puzzle is for whatever reason it is only happening with this rifle. A learning experience for sure.

Get your firing pin bushed and I'll bet your problem goes away. You say the firing pin is not dragging, how do you know?

I meant to say the spring is not dragging-it's very straight.

Turns out the bolt handle was striking the receiver on the underside (I put some mole skin on it for now and the hop went away)

As for the trigger problem the Rifle Basix trigger was crooked to one side causing me to torque it. I replaced it with a take off from a KS and it's straight and breaks easily. I'm guessing the reason the RB broke at 2.5 on the scale was due to the narrow hook instead of a finger.

I appreciate all the input. Hopefully this one goes back to normal. I'm puzzled about the trigger-I've had nothing but good luck with Rifle Basix's, I thought at first it might have been a bedding issue that canted the trigger but that turned out not to be the case.

Put a fired cartridge that still has a primer seated into the chamber, dry fire the rifle and see what happens. You should be able to balance a quarter on the barrel at the muzzle that won't fall off when the pin falls.