help diagnosing accuracy problem

[jcampbellsmith]

Here's a man who likes 'free recoil' - Stecker Succeeds at SWN with Radical Benchrest-type F-TR Rig Daily Bulletin
The Americans who trained me to shoot with a bipod wouldn't dream of holding the fore end.

Regards JCS

 

[.25-06]

I like the idea of golf balls etc. Any idea what a 150gr ballisitc tip does to a golf ball?

Knocks a surprisingly small chunk out of it.

 

[Muir]

The Americans who trained me to shoot with a bipod wouldn't dream of holding the fore end.

Regards JCS

That isn't always hold true with sporting rifles. I agree with the OP. Sometimes a hand on the foreend is what is needed. My BAR 30-06 requires a hand on the foreend for any kind of accuracy. If you shoot standing (I know, not popular there) you'd better have zeroed with a two handed hold.~Muir

 

[charlieboy-shooter]

Thanks for all the suggestions.

I am holding the forend, just behind the bipod. I do this with the .308 otherwise I get too much 'jump'. I try not to force it down - just hold it steady. I suspect that there may well be quite a lot of variation here.

Stock is a standard classic stock (ie. not Monte Carlo and not stutzen). Cheek is a little low for the high rings, so I do have to cock my head slightly (which is not ideal).

Nothing done to rifle since last 'good' session.

Trigger pull may not be as consistent as it could be - I do have a marked tendency to snatch and flinch, and have been trying to train myself out of it. Any suggestions for the best way to do this are very welcome (plenty of work with a .22Lr probably...).

Hi,

Just a thought and I'm no expert but, if the rings are a bit high and you have to cock head slightly. Could some of the issue be this? if you fire a 3 shot group after lying down and mounting the gun. Then change target and re-mount, head postion slightly different and hence POI shift, but shoot a group again but just different point. I have an Accucover on a couple of scopes. This has 4 triangular marks on the edge of the cover which you line up with the cross hairs. Shows if you are looking through scope true each time. It certainly removes that variable for me.

 

[JMS906]

I'd be grateful for help diagnosing a niggling accuracy problem:

I have a recently acquired .308, with a 6X42 scope in swing off mounts. For the purposes of this, it was being shot off a bipod.

You are going to be hard pressed to shoot small groups at 100 yards with a scope of only 6x. It might be worth you dropping down to 50 or 75 yards.

How many groups did you shoot in your first session? How many rounds in a group? And how many of those groups were under an inch, all of them or just some of them?

Clearly, your later session produced larger groups. There could be many reasons for this. Were you shooting outside - exposed to wind and distractions - or indoors? Were you shooting at the same venue? Were you using exactly the same ammunition? Wearing the same clothing? Was the weather and lighting conditions the same? How often and how well do you clean the barrel?

However, there was a distinct pattern to the shots: the first in each subsequent group of three went almost through the same hole (ie. if I were to only take those shots, there would be a very nice group indeed). The second went about half an inch high and a touch to the left, but with more variability, and the third about an inch and a half high with a lot of variability.

That could be due to the barrel heating, or to you getting tired and inconsistent or developing a flinch.

So my question is this: is such a pattern likely to be the product of something shifting as the barrel heats up with each successive shot in a group? Or can it be explained by my tendency to develop a flinch?

The heatng theory is easily tested. Fire ten rounds in fairly quick succession and observe the results.

The flinch theory is also easily tested. Get a mate to load each cartridge for you, out of your visiosn, and then hand the rifle to you. Some times he hands you a loaded rifle, sometimes and empty rifle. If you are flinching, your mate will fall over laughing and you snatch on an empty chamber.

I am inclined to go with the latter, since I had been shooting clays the day before, and had quite a nice tender bruise on my shoulder. If it is the latter, is such a consistent pattern to a flinch normal?

That is probably relevant. Buy yourself a 'sissy' pad for your shoulder. And fit a soft butt pad on your shotgun!

-JMS

 

[nowler]

Scrub and clean the barrel. It's probably heavily fouled.

 

[Muir]

You are going to be hard pressed to shoot small groups at 100 yards with a scope of only 6x.

-JMS

I can center a 1" circle at 100M with my Zeiss on 6X and shoot 1/2 MOA in the process. Besides, if he moves in to 50M he will start inducing more parallax, I'm wagering.~Muir

 

[6mmAI]

just a thought if you are flinching, is it because of the muzzle jump...? if so have you considered a muzzle break? I had one on my 6.5x55 as I couldn't bare the muzzle flick.

 

[Sika98k]

Hi, You mention swing off mounts, what make? These can cause issues when not set up right, especially apel. Though when set up are great.

Regards - K

I think Karamoja may have hit it on the head here. No personal experience myself but it has happened to a friend using Apel mounts,screw came loose and I believe they do wear.

 

[Mungo]

just a thought if you are flinching, is it because of the muzzle jump...? if so have you considered a muzzle break? I had one on my 6.5x55 as I couldn't bare the muzzle flick.

The muzzle jump isn't really that bad - it's just a bit of a 'bounce' when using a bipod - I think this is quite common with bipods.

My flinch has a much more prosaic explanation - it's a tendency to anticipate the shot and snatch the trigger, and it seems to be largely independent of calibre. Did a bit of shooting with the rimfire over the weekend and worked on ironing it out, and that seems to be helping. It's something I've always had, and it comes and goes every few months. As soon as I notice it creeping back, I set to work at getting rid of it.

 

[Mungo]

You are going to be hard pressed to shoot small groups at 100 yards with a scope of only 6x. It might be worth you dropping down to 50 or 75 yards.

I'm not sure this is the problem. It certainly wasn't the problem at previous sessions, or when I use my other rifles. I don't think I'd try zeroiing at 200 with a 6X42, but certainly don't find it hard at 100.

How many groups did you shoot in your first session? How many rounds in a group? And how many of those groups were under an inch, all of them or just some of them?

6 groups of 3. All groups at or under and inch.

Clearly, your later session produced larger groups. There could be many reasons for this. Were you shooting outside - exposed to wind and distractions - or indoors? Were you shooting at the same venue? Were you using exactly the same ammunition? Wearing the same clothing? Was the weather and lighting conditions the same? How often and how well do you clean the barrel?

Shooting outside. Same venue (exact same shooting position, in fact). Same clothes (unwashed in between too, much to my wife's distress). Came ammo (same LOT number). Same weather, same time of day. Barrel cleaned thoroughly every 20-30 shots.

That could be due to the barrel heating, or to you getting tired and inconsistent or developing a flinch.

Both of the above seem to be the leading contenders (with my money on the flinch).

The heatng theory is easily tested. Fire ten rounds in fairly quick succession and observe the results.

Good idea - thank you. I will try that to satisfy my curiosity.

The flinch theory is also easily tested. Get a mate to load each cartridge for you, out of your visiosn, and then hand the rifle to you. Some times he hands you a loaded rifle, sometimes and empty rifle. If you are flinching, your mate will fall over laughing and you snatch on an empty chamber.

Or just shoot with the rimfire, and watch the first group spray like a shotgun blast!

 

[DCG]

If you're doubting your'e own ability, next time your'e at the range, get someone else of proven ability to shoot the rifle. If it one holes then its you. If it exhibits similar results, then it's the rifle. Simples
dcg