Is it Me? Has anyone ever seen this?

[armbar]

I recently took possession of a brand new Fierce Titanium Carbon in 300WM. I topped it off with a Leopold VX-6HD 3x18. Nightforce rings and a Piccatinny rail mount. The rings and bases have been Loctited. I shoot sitting from a bench, I use a Caldwell Tack Driver for the front rest and a standard leather covered V rest for the rear. It never grouped consistently as well as it should. Some groups were good, others not. After reading here, I began dry firing it at the range. I noticed that about 9 out of 10 times at the dropping of the firing pin, the point of aim would shift. Usually to the left, but not always. Sometimes it would go up slightly. On occasion it would go right slightly. So today I set out to fix this problem, assuming it was me. I again began dry firing while adjusting my grip, varying how firmly I held the rifle, and working on natural point of aim. I worked on a smoooooth trigger pull, no flinch, and pulling the trigger STRAIGHT back. I played with how firmly my cheek was on the stock. I put my left hand on the top of the scope, on the fore end and didn't let anything touch the barrel. I tried putting the rifle on the rest, without ANYTHING touching it except my trigger finger, and at the drop of the firing pin it still happened about 9 out of 10 times! When it didn't, I couldn't figure out if I had done anything different. I tried dry firing my Blaser after this and didn't get any shift. My friend dry fired mine and he saw the same thing. Has anyone ever seen this? It's driving me crazy! Heres pictures of my targets today at 100 yards. If you look close enough, you can see my notes on the targets.
Any help is greatly appreciated!

 

[dfanonymous]

You checking for parallax shift?

 

[armbar]

Yes. I adjusted for parallax before the first shot. But I don't think that's how parallax manifests itself.

 

[Plinker147]

Yeah that sounds like your parallax isn't set right for the distance your shooting.

 

[sika64]

Have you checked the receiver screws on the stock to make sure they are torqued to specs ? Or the trigger to make sure it is tight ?

 

[dfanonymous]

Yes. I adjusted for parallax before the first shot. But I don't think that's how parallax manifests itself.

Adjusting is one thing. I want to know if you checked to make sure it was gone by moving your headside to side and eliminating reticle swim. That is exactly how parallax manifest itself, if I'm understanding what you are explaining.

 

[Plinker147]

Read the sticky in long range scopes section if you haven't already. it's a good read and will help to eliminate possible paralllax problems for your issue

 

[lancetkenyon]

ULRS...Ultra Lightweight rifle syndrome.

Not enough mass to keep a stiff firing pin spring from slightly moving the entire rifle. Watch the bolt jump when you dry fire it.

Those ultra lights are made to be carried all day and shot across 300-500 yard canyons. Not 1000 yard ones.

 

[memtb]

While "not" as obvious on a rifle as a handgun.... if all else is good, possibly trigger pull weight and trigger overtravel. The greater the trigger pull, the greater the firearm movement "if" you have excessive overtravel!

My layman's exaggerated graphic depiction of the effect of "overtravel" is this. Imagine that you are in a tug of war, and someone cuts the rope....you'll likely stumble backwards onto your butt. Now same scenario, but you have a wall 1" behind you, when the rope is cut. You movement is much less exaggerated or violent!

Again, this is much more noticeable with a scoped handgun, than is with a rifle. But, some rifle movement may be generated just at the moment the sear is broken! memtb

 

[Aoudad shooter1975]

Light rifles are harder to get those one hole type groups...im going to side with LanceKenyon

 

[dfanonymous]

My only confusion is the 9 out of 10 times. While I agree that a light weight rifles heavy firing pin could certainly be the issue, but still siding with my theory of parallax, wouldn't it be a little more consistent then 10 out of 10 times since a spring wouldn't loosen up randomly during dry fire I would imagine. Also I've never opened my groups over an inch because a trigger was heavy on any gun, including double action pistols, but parallax has open my groups anywhere from a half inch to over an inch, since parallax has more effect at shorter distances then longer.

 

[SMK1000plus]

Sounds like you've got your fundamentals of marksmanship where you want them. That leaves mechanical issues...

When dry firing, how much POA shift are you seeing when the firing pin drops? (preferably in terms of MOA or Mils. Just specify which you are using) It is unusual that the shift isn't varying in one general direction.

Is the action bedded? Could your action be shifting in your stock? Have you tried a different scope? Is it possible that your reticle is moving because of the jolt of your firing pin impact? Possibly but, not likely, a lense loose or internal scope tube cracked. Maybe a Picatinny rail mount to rifle loose? I use J.B. Weld Steel epoxy to stress-free bed my Picatinny mounts to my rifles. (PM me if you want details of the procedure I use).

After you've checked all the usual culprits, you may want to try a lightweight firing pin (titanium or fluted) and a lower poundage firing pin spring.

 

[SMK1000plus]

lancetkenyon is absolutely correct about the possibility that you are experiencing Ultra-Lite rifle syndrome but, that can usually be mostly negated by the techniques that you've described as having already tried.

While ultra-lite rifle syndrome is actually a mechanical issue caused by a lower mass rifle and a heavy firing pin/spring, it usually manifest itself in a non-uniform or inconsistent amount of travel/motion in a single general direction, not typically in random directions. Are you sure that the POA shift is random, and that you are not occasionally also muscling the rifle, compounding another issue?

 

[Greyfox]

While this may not be the cause of the OP's dispersed groups, I have observed this type of dispersion with very light /heavy recoil rifles. If I had any success at minimizing the effect, short of rifle modifications, it was achieved by using an exceptionally hard and consistent hold at the grip and forearm in order to reduce and control pre bullet exit, barrel flip.