Outstanding in my field
Well-Known Member
Booked in on the range on Saturday morning to see If can get to the bottom of this. Will post the results.
Hot barrels and wandering zero?
- Thread starter Outstanding in my field
- Start date
Don't go to the other extreme and demand zero poi shift !
I have had slim barrels and they do move a bit after a few shots, but not so a deer would ever notice. Maybe that's a reflection of the quality of barrel but hey we are shooting factory barrels on a budget rifle.
I have had slim barrels and they do move a bit after a few shots, but not so a deer would ever notice. Maybe that's a reflection of the quality of barrel but hey we are shooting factory barrels on a budget rifle.
Heym SR20
Well-Known Member
I would suggest that several things are happening here.
As steel gets hot it expands. A barrel is a steel tube and if it's not perfectly concentric there will be thicker steel on one side than the other and hence the barrel will warp. Modern barrels made on modern machinery will tend to be much more consistent.
With heat there may well be an impact on bedding / action etc. But much more likely will be the effects of
1) Mirage - especially noticable in still air, in an indoor range etc. Barrel is hot, you get warm air above the barrel which can cause refraction of light as it passes from warm to cold and back again. This can have quite an effect on shot placement. In effect your target is moving about.
2) Fatigue. You say that you are new to centrefire shooting. It takes time to learn how to shoot and manage the recoil of a centrefire rifle. Even a lightweight 243 can cause enough discomfort if several shots are fired in succession. Take it up to a 308 and a newbie, its a level of recoil that very quickly becomes an issue. What then happens is that hold of rifle, body position etc goes to pot and you start flinching as you squeeze the trigger. And because the group opens up, you start to get irritated, so you start getting tense, so start pulling shots and then the whole things goes to rat ****.
If you are testing loads the secret magic ingredient is time and lots of it. Yes appreciate @Edinburgh Rifles comments above, but Ed is a very accomplished marksmen - much better than most of us. I have always taken the view that its first shot that counts, and I want each test shot to be from a cold barrel. When hunting I have only a very few times taken a follow up shot with a warm barrel.
My advice is take two additional bits of kit with. One being a 22rf, the other the ability to make tea. And it works like this.
Take a shot with the centrefire, put kettle on, load 22 rimfire magazine and shoot five or ten rounds. Fire another round at the same target, make the tea, another five or ten rounds with 22rimfire, Fire another round - leave bolt open and walk up to target and marvel at the small size of your group. Amble back to the firing point - drink tea glowing in the satisfaction of your little group. Open the different ammo and repeat the above process.
I can easily spend a couple of hours and only shoot a very few rounds, but learn a lot. Or I could send 20 rounds downrange, get a hot barrel and sore shoulder and learn nothing apart from how much it costs.
As steel gets hot it expands. A barrel is a steel tube and if it's not perfectly concentric there will be thicker steel on one side than the other and hence the barrel will warp. Modern barrels made on modern machinery will tend to be much more consistent.
With heat there may well be an impact on bedding / action etc. But much more likely will be the effects of
1) Mirage - especially noticable in still air, in an indoor range etc. Barrel is hot, you get warm air above the barrel which can cause refraction of light as it passes from warm to cold and back again. This can have quite an effect on shot placement. In effect your target is moving about.
2) Fatigue. You say that you are new to centrefire shooting. It takes time to learn how to shoot and manage the recoil of a centrefire rifle. Even a lightweight 243 can cause enough discomfort if several shots are fired in succession. Take it up to a 308 and a newbie, its a level of recoil that very quickly becomes an issue. What then happens is that hold of rifle, body position etc goes to pot and you start flinching as you squeeze the trigger. And because the group opens up, you start to get irritated, so you start getting tense, so start pulling shots and then the whole things goes to rat ****.
If you are testing loads the secret magic ingredient is time and lots of it. Yes appreciate @Edinburgh Rifles comments above, but Ed is a very accomplished marksmen - much better than most of us. I have always taken the view that its first shot that counts, and I want each test shot to be from a cold barrel. When hunting I have only a very few times taken a follow up shot with a warm barrel.
My advice is take two additional bits of kit with. One being a 22rf, the other the ability to make tea. And it works like this.
Take a shot with the centrefire, put kettle on, load 22 rimfire magazine and shoot five or ten rounds. Fire another round at the same target, make the tea, another five or ten rounds with 22rimfire, Fire another round - leave bolt open and walk up to target and marvel at the small size of your group. Amble back to the firing point - drink tea glowing in the satisfaction of your little group. Open the different ammo and repeat the above process.
I can easily spend a couple of hours and only shoot a very few rounds, but learn a lot. Or I could send 20 rounds downrange, get a hot barrel and sore shoulder and learn nothing apart from how much it costs.
bore scope will tell you nothing.
it may look perfect - in which case what have you proved
it may look like the surface of the moon - in which case you will assume the condition is causing the problem.
Case in point:
Barrel condition
Before cleaning: After cleaning: two careful owners. Discuss:
www.thestalkingdirectory.co.uk
Worst barrel I have ever seen.
By far the most accurate rifle I have ever use at 100m and out to 1200m
Rewulf
Well-Known Member
A strange comment , you dont use a bore scope then , for any reason ?
But then you say...
So it has told you something, has it not ?
If you took in a used rifle , for which the owner told you it had lost accuracy, would you not take a look at the bore and see if there was a shot out throat , or a corroded crown , dangerous pitting or cracks ?
If the bore scope tells you nothing, how will you know it isnt the bore that is worn ?
Will you just assume its something else. pilot error , or cheap scope mounts ?
Like I say, very strange comment from an expert.
A 4" group at 100 yards is not acceptable, even for those of use who judge groupings based not on cloverleafs but simply as "close enough for government work" 
Therefore I would suggest you systematically remove all variables to find the root cause.
Not sure if you are using a moderator, but start by taking the moderator off the rifle and have a look at the business end to see if there is any shiny metal, as evidence of the bullet clipping the mod on it's way through. It is surprising how many times the moderator turns out to be the issue, but fortunately it is also the easiest variable to remove.
If the moderator looks okay, shoot a group without it fitted to the rifle.
Check if the group is okay. If it is, the moderator is likely the root cause, but by all means fit it back on the rifle and fire a three-shot grouping to check,
If it still isn't grouping without the moderator, make sure the mounts are correctly fitted, that every nut and bolt is tight, and shoot another group.
If it still isn't grouping, get someone else to fire a three shot group.
If it still isn't grouping, start looking at the loads themselves - try some different makes of factory ammo in different bullet weights.
If it still isn't grouping, I'd be thinking of taking it back to the shop you bought it from.
Therefore I would suggest you systematically remove all variables to find the root cause.
Not sure if you are using a moderator, but start by taking the moderator off the rifle and have a look at the business end to see if there is any shiny metal, as evidence of the bullet clipping the mod on it's way through. It is surprising how many times the moderator turns out to be the issue, but fortunately it is also the easiest variable to remove.
If the moderator looks okay, shoot a group without it fitted to the rifle.
Check if the group is okay. If it is, the moderator is likely the root cause, but by all means fit it back on the rifle and fire a three-shot grouping to check,
If it still isn't grouping without the moderator, make sure the mounts are correctly fitted, that every nut and bolt is tight, and shoot another group.
If it still isn't grouping, get someone else to fire a three shot group.
If it still isn't grouping, start looking at the loads themselves - try some different makes of factory ammo in different bullet weights.
If it still isn't grouping, I'd be thinking of taking it back to the shop you bought it from.
long_range_rob
Well-Known Member
Check your action screws, check your bedding, check your free floating is actually floating then sell it and buy a Sako.
We use borescopes all the time.
it will tell me if it is rusty
not if it shoots or doesn't shoot.
There are rifles that are perfectly serviceable and shoot well but we couldn't sell because they look very rough inside.
Only reason I would borescope the OPs bergara was to confirm if he had been sold a rifle as described. (Light use)
Condition and accuracy are not always linked.
It won't confirm that the accuracy issue is solely down to bore condition.
Far too many variables
Lets say it is bore scoped and comes up clean.
Then what?
Do you exclude the barrel as the issue?
Or if its looks like a tarmac road inside
and you conclude it MUST be the bore as the sole cause.
You cant
its a nice to have
only the paper is true
When target shooting I don't have time to be leisurely on the firing point so I shoot all my rifles with long strings and they get so hot that the barrels actually sweat oil out of the wood work. All of them keep POI despite a variety of barrel thicknesses and lengths. Some are free floated, some are pressure bedded into the wood. The usual mechanical explanation for a newish rifle wandering is the bedding is not up to standard (or action screws loose) or the forend is touching the barrel.
I had a similar situation? When you are ready to take your FIRST' shot,try and make it the best' shot you've ever taken, and be honest with your self with the out come. Good or bad, do not rush to get the next one away,(warm barrel now) be deliberate, and take the exact same point of aim. If you are happy with the result ,then you are made up, if not then the reason of failure will be simpler to establish. Good luck.
BC.
long_range_rob
Well-Known Member
Ed’s quite right on borescopes. They show you everything but not what it means. Look at the cutting edge of a scalpel through an electron microscope and it’ll look like a cross between a knackered felling saw and the Himalayas, but that doesn’t mean it won’t cut.
I’ve had pitted rifles that shot (clean everything religiously now) I’ve even had a bulged .308 decades ago that still shot 1/2 MOA
I’ve had pitted rifles that shot (clean everything religiously now) I’ve even had a bulged .308 decades ago that still shot 1/2 MOA
This
I would concentrate on achieving small 3 or 5 shot groups before doing anything else. I would check every screw on the stock and scope mount. As mentioned someone else who is a proven shot would be a great idea to test whether it is something you are doing or not doing, or whether it's your setup. I did get told a tale that a "experience" shot could get a new rifle to group. A friend of his went to the target with him only to see the guy resting the barrel on the sticks. Problem solved.
I bench mark is 1 moa max. If I am not achieving that then there is something wrong.
One of my old mentors said if he had a rifle and groups opened up to 1/2 moa he would be checking it out and it might be shot out and it would be rebarrelled or sold. I did consider buying his shot out stuff but they were usually too heavy to stalk with
I bench mark is 1 moa max. If I am not achieving that then there is something wrong.
One of my old mentors said if he had a rifle and groups opened up to 1/2 moa he would be checking it out and it might be shot out and it would be rebarrelled or sold. I did consider buying his shot out stuff but they were usually too heavy to stalk with
It should be "
Should read experienced shot could not get a new rifle to group
Rewulf
Well-Known Member
You stated it would tell you nothing?
It will also tell you if it's pitted, cracked, worn or damaged, what you're saying though is this doesn't necessarily mean that's the problem, which could be the case, or not...
We know it shoots, it supposedly doesn't shoot accurately after a few rounds, but that's not why I suggested a borescope.
This is why, and if the barrel is rough, send it back = goods not as described.
No, and no, obviously, but not using or ignoring the tool makes no sense.
It's like a doctor not bothering with an MRI or x Ray, because it might not tell you exactly what's wrong with a patient.
Also, dont let your round sit in a hot chamber for any length of time before shooting, it will raise power temp and cause change to velocity and harmonics.
Shoot a 10-shot group from a bench with aid of a rear bag and post result,
K
K
All SH rifles are 'Barely shot by previous owner' - Barely is relative!
Neither of those comps are really about tiny group accuracy though are they?
Agreed: they are about deer accuracy.
But the “grouping” was about 6” on running targets for both tests, with no signs of vertical stringing (in this case, that should have shown the later rounds consistently striking higher), even when the barrel and moderator got VERY hot.
I would be interested as to what other people have measured in terms of vertical stringing, and after how many rounds?
The OP is talking about a 4” group and random POI - not sure after how many rounds. But if, let’s say, 5-10, I suspect that less than half of that is barrel heating (and the later rounds should be seen to start wandering upwards), and a majority is something else, whether setup or fatigue/technique. It’s those latter issues that need addressing.
But the “grouping” was about 6” on running targets for both tests, with no signs of vertical stringing (in this case, that should have shown the later rounds consistently striking higher), even when the barrel and moderator got VERY hot.
I would be interested as to what other people have measured in terms of vertical stringing, and after how many rounds?
The OP is talking about a 4” group and random POI - not sure after how many rounds. But if, let’s say, 5-10, I suspect that less than half of that is barrel heating (and the later rounds should be seen to start wandering upwards), and a majority is something else, whether setup or fatigue/technique. It’s those latter issues that need addressing.
Similar threads
