.244 H&H Mag. group shift problem.

[Mack The Knife]

Not sure if the following comes in the gunsmithing or rifle section and I am supposed to be a moderator... Please shift it if you think it's necessary.

A friend called me up last night for a solution to his shooting woes.

He has a .244 H&H Mag. that was made by Holland for his grandfather. So, it's an old rifle but most probably in very good condition, i.e. the barrel hasn't been shot out. I have yet to see it.

He finds that the groups shift approximately 8" to the left or right of zero after about 6 to 8 continuous shots. This is happening with both factory and reloaded ammo.
His reloaded ammo matches the factory ammo's muzzle velocity of 3300 to 3400 ft./sec. and he is using 100 grain bullets over 61 grains of IMR 4350.

I have heard of groups opening up when the barrels get hot but nothing about a shift in zero. Please correct me on this if it is otherwise.

When he noticed this problem, he mounted a scope thinking that it was probably the sights that had developed a fault. However, the problem still persists.

He has checked the scope mounts for shift and assures me there is none.

I also had him check the stock screws and crown and he reported back saying that there was no problem here either.

I have asked him to check if the barrel is free floating and he will get back to me on this.

When talking to him, I asked him if he cleaned the bore before switching rounds. He hadn't. All his bullets are copper jacketed. Would cleaning the bore have an effect and more to the point, how many shots would it take a centre-fire to group from a freshly cleaned bore? I am assuming none to a couple but would like to hear from the centre-fire shooters.

I may be range testing this rifle sometime during the week but until then this is all I have to go on.

If you know of a similar problem and a solution to it, I'd like to know what it is.

Thanks.

Mack The Knife

[Mark]

Without looking at the gun, it sounds like a stock/bedding problem to me.

See if you can slide a thin strip of paper around the barrel or if it binds on one side.

Loosen up the action bolts and put a shim made from a business card under the barrel right next to the action and see if it cures the walking problem. The groups may open up, but at least you have figured out the problem. Having the gun rebedded should solve the problem. If the stock is pressing on one side of the barrel shaving away a tiny bit (of the stock) may solve the problem too but I try not to recommend that before everything else has been checked.

Also, another thing it could be is the shooter, try having someone else shoot the gun just to make sure.

[Mack The Knife]

Thanks for the suggestions, Mark. Have sent the person concerned a link to this thread and I am sure he will keep an eye on it and try whatever is being recommended.

Regards.

Mack The Knife

[eljefe]

Mack The Knife,
Agree with Mark.Most likely a bedding problem.Has by any chance, a screw sheared?That passing a business card trick would clue us in.
best
Axx

[Mack The Knife]

He has checked the barrel for free float and did not have a problem. He is going to try Mark's sggestion next after he oils the inletting.

Will keep you chaps apraised.

Thanks.

Mack The Knife

[eljefe]

If you need help with a new stock, met this 3rd gen stock maker here in Delhi, guy is really talented-a stock for a 30-06 was amazing-schnabel fore end et al! Real Kashmir walnut too.
Best
Axx

[Mack The Knife]

Thanks Asif, will keep it in mind. How neat was the inletting, was the chequering sharp and did you get to try it with the action bolted in? Just curious if he got the LOP, height of comb, etc. right.

Lost faith in Indian gunsmithing skills but it would be reassuring to know that there may still be a few who can do a good job.

Mack The Knife

[Grumpy]

Just as a matter of interest when was the last time the barrel was cleaned ? Won`t affect the wandering zero but will make a difference to general accuracy if there`s a load of copper in the rifling.
Something else to try is to support the rifle under the action - preferably with a sandbag - rather than under the fore-end. If it then shoots true the fore-end is definitely pressing againt the barrel when supported normally. The fact that the zero moves so consistently is interesting......Asifs suggestion of a stripped or loose bedding screw seems most likely. I presume that being an H&H that the action is a Mauser 98 ?

[Mack The Knife]

Just as a matter of interest when was the last time the barrel was cleaned ? Won`t affect the wandering zero but will make a difference to general accuracy if there`s a load of copper in the rifling.

No idea Grumpy. It certainly wasn't cleaned before switching from factory to handloaded ammo.

Something else to try is to support the rifle under the action - preferably with a sandbag - rather than under the fore-end. If it then shoots true the fore-end is definitely pressing againt the barrel when supported normally.

Many thanks for this suggestion. Will pass it on.

The fact that the zero moves so consistently is interesting......

Any explanation for this?

Asifs suggestion of a stripped or loose bedding screw seems most likely.

He did check the stock screws and said they were tight. Would a stripped screw not be loose?

I presume that being an H&H that the action is a Mauser 98?

Probably but unable to confirm this at the moment.

Thanks.

Mack The Knife

[Mark]

Here is something else to help you diagnose this-

Remove the action from the stock (since it is not shooting well I suppose he will have no problem with this)

There is a spray you can buy here made for atheletes foot, that has talcum powder in it. Spray the inletting of the stock, then carefully replace the action and tighten down the screws. Then carefully remove the action and examine the stock for where the contact/rubbing takes place. Also check to make sure the trigger does not rub on the stock. You can also spray the action and repeat the process.

Here's another idea- I remember hearing a long time ago that a loose rear screw will cause vertical stringing, and a loose front screw will cause horizontal stringing. Your friend says the screws are tight. Since it is an old gun could it be possible the stock has compressed to where the front screw is bottoming out? Possibly a small washer or 2 under the screw head would take up the slack and allow you to see if this is the problem. You may be able to squeeze the fore end and see if the screw moves a tiny bit.

[eljefe]

Mark& Grumpy-
seems like we're reaching a common consensus on Tele gunsmithing-Its all in a screw-tongue firmly in cheek!
Yeah, agree about the influence of the front screw and horz stringing etc.Most times, these oldsters are well handled , but due deference must be given to a little overenthusiastic 'tightening'.The shim is another good way of checking out.Logic dictates that there is most likely a problem to do with the barell retention to the stock.After finding the culprit, would it help to pillar bed the rifle?
Mack The Knife,
Checkering was sharp, LOP etc was tailored to the client I believe.Yeah, at one time, going by the 'bedpan mechanic' that we have been exposed to , I would agree with you, but we do find a diamond like this youngster , who does nothing but stock work.He wont give Fajen or Macmillan a run for their money yet, but with a encouragement and exposure, he can.
best
Axx

[Mack The Knife]

Since it is an old gun could it be possible the stock has compressed to where the front screw is bottoming out?

Mark,

This could well be the problem.

Thanks.

Mack The Knife

[.375Double]

Asif,

Is this stock maker called Shamsuddin near Delight cinema house in Delhi ?

If not please let me have his details and whether he can do a 24" checkering accurately.

Thanx.

[kanwar76]

Asif,
Is this stock maker called Shamsuddin near Delight cinema house in Delhi ?
Thanx.

Somebody referred the same guys to me also when I was looking for someone to make stock for my National Air-rifle . Don't know about his stock making abilities but looked pretty genuine to me.
he advise me against it as cost of making stock would exceed the value of the rifle

Over to you Asif

Inder

[mundaire]

I recall getting an IHP National CO2 air-rifle stock modified along with the installation of better (more adjustment options) iron sights installed by the same chap - Shamsuddin. This was some 15-20 years or so back and he did a rather crude job on it

Maybe his skills have improved in the intervening time...

Cheers!
Abhijeet