Barrel Heating Conundrum

[motivationteam]

I have searched and can't seem to find any info.
Here is the deal-
I have a Savage BVFS in 22-250. I have have had it for several years. My problem is that I work up loads and invariably it shoots pretty good on the final groups.
So then I think I have a good load. Then when I shoot it again later the groups open up.
This has confused me for a long time. What I have learned is the it only shoots good when the barrel is hot. When the barrel is hot it will shoot 1/2 inch. When the barrel is cool it shoots 2 inches.
Thinking it was a bedding problem I bedded the action, I did it myself so maybe I did not do a good job but it still only shoots good when the barrel is heated. I have tried every combination I can think of when it comes to bullet and powder combinations and seating variations.
So now I am thinking 2 things-
1. Re-bed the action and see if that fixes it.
2. Put a new barrel on it.

Can anyone shed some light on this conundrum?

 

[Medic505]

Is the barrel free floated or does it touch anywhere?

 

[motivationteam]

It is free floated. I did bed the first 1 inch of the barrel.

 

[Mark W]

Sounds like a good prairie dog rifle!!

 

[carlsbad]

bedding under the first 1" of the barrel would be something I would suspect as the culpret, I don't recommend it, but since the problem existed before and after the bedding job, then it probably isn't the problem.

You should check to makes sure you don't have an interference that opens or closes with temperature. Look at all the rail screws and make sure they aren't hitting the bolt. Make sure your action screw isn't into the barrel threads. Make sure you don't have contact between your bolt nose and your barrel tenon that could open up or close with temperature.

Make sure your barrel is tight on the action.

I assume you have a barrel nut, if your nut flange isn't square or has a burr, that could change with temperature.

 

[1911nut]

If you put a Shilen barrel on it and it shot way better then you would know.

I got three Shilen barrels on Savage target actions, they all shot better than I expected and they all put a clean barrel first shot in the group.

 

[JFrank]

I have searched and can't seem to find any info.
Here is the deal-
I have a Savage BVFS in 22-250. I have have had it for several years. My problem is that I work up loads and invariably it shoots pretty good on the final groups.
So then I think I have a good load. Then when I shoot it again later the groups open up.
This has confused me for a long time. What I have learned is the it only shoots good when the barrel is hot. When the barrel is hot it will shoot 1/2 inch. When the barrel is cool it shoots 2 inches.
Thinking it was a bedding problem I bedded the action, I did it myself so maybe I did not do a good job but it still only shoots good when the barrel is heated. I have tried every combination I can think of when it comes to bullet and powder combinations and seating variations.
So now I am thinking 2 things-
1. Re-bed the action and see if that fixes it.
2. Put a new barrel on it.

Can anyone shed some light on this conundrum?

It’s you

 

[Texas10]

Scope parallax could be an issue, what scope are you using?

Savage does use cold forming to straighten out crooked barrels, and these will move as they heat up and stresses change.

One thing that happens when your barrel is getting hot is that you are getting time behind the trigger getting and into your groove, and this alone may explain some of the grouping issues, but 2 inches tightening up to 1/2 inch sounds more like a mechanical issue.

Two things you can check immediately: Run a .005 feeler gage around the rear tang and make sure it's not tight against the stock. Use a dremel tool to sand out wood until it is free floated. When installing the barreled action into the stock, make sure it's straight and not slightly off to one side where it can contact the stock.

If your recoil lug is trapped in your bedding, remove material from the front side of the lug so it's bedded only on the aft side. You may want to remove bedding from under the nut and barrel at this time, also.

If you haven't already done so, you might want to check out this torque tuning article for Savage actions.

https://www.accurateshooter.com/technical-articles/savage-action-screw-torque-tuning/

If nothing seems to help, it's time to think about a new barrel with precision ground nut and lug. If you buy the tools and do it yourself, the knowledge you'll attain is well worth the small investment.

 

[joshb]

It’s you

SPJ May sound like he’s joking but there is a serious point behind it. I don’t shoot my best groups until “I” warm up.
I’m excited and jittery when I hit the range. It’s usually early in the day and I’ve just had 4 to 8 cups of strong coffee. I usually settle into my groove after a couple hours. I learned to compensate by shooting my 2nd string guns in the morning and my better guns after noon. This lets me end the day on a high note and feeling good about my shooting.

 

[Daddymac]

Lucky dog, mine usually go the other way!
If you continue to shoot, will the rifle maintain 1/2" or will it open back up?
I'm going to ask you experts a question, please don't laugh too loudly if it's super dumb, if the barrel is too tight or under size when cold, and has a tight bullet to barrel fit, but a better fit when hot and expanded, could something like this be the problem, or am I just a DA.
Possible dumb question #2, if the answer to the above is yes, would lapping or polishing the barrel be a solution?

 

[Zero333]

Maybe the scope ?

 

[gambleone]

SPJ May sound like he’s joking but there is a serious point behind it. I don’t shoot my best groups until “I” warm up.
I’m excited and jittery when I hit the range. It’s usually early in the day and I’ve just had 4 to 8 cups of strong coffee. I usually settle into my groove after a couple hours. I learned to compensate by shooting my 2nd string guns in the morning and my better guns after noon. This lets me end the day on a high note and feeling good about my shooting.

This what joshb & SPJ says, very true. I find myself doing same thing.
As much as you think it "it can't be me," it very well good be.

 

[rwj]

It’s you

That’s where I always start when having problems!

Just to add some “spice” to the dialogue... accuracy may improve with temperature due to thermal expansion. As temperature increases, so does the object’s volume. Though not commonly realized, the ID of a cylinder initially gets smaller before it gets larger during heating. The effect being more pronounced when heated from the inside. So perhaps the barrel is becoming smaller and gripping/stabilizing the bullet better when it’s hot? Let the flaming begin!

 

[muleman69]

bedding under the first 1" of the barrel would be something I would suspect as the culpret,

How should a person bed in front of lug as a rule?

 

[rwj]

SPJ May sound like he’s joking but there is a serious point behind it. I don’t shoot my best groups until “I” warm up.
I’m excited and jittery when I hit the range. It’s usually early in the day and I’ve just had 4 to 8 cups of strong coffee. I usually settle into my groove after a couple hours. I learned to compensate by shooting my 2nd string guns in the morning and my better guns after noon. This lets me end the day on a high note and feeling good about my shooting.

I absolutely agree that the shooter is a huge factor in the accuracy equation! Interesting that there isn’t much discussion about it in the various forum threads that seem to focus primarily on technical aspects. How could we get such a thread started... hmmmm?

 

[muleman69]

That’s where I always start when having problems!

Just to add some “spice” to the dialogue... accuracy may improve with temperature due to thermal expansion. As temperature increases, so does the object’s volume. Though not commonly realized, the ID of a cylinder initially gets smaller before it gets larger during heating. The effect being more pronounced when heated from the inside. So perhaps the barrel is becoming smaller and gripping/stabilizing the bullet better when it’s hot? Let the flaming begin!

Could very well be something to this, seems like bolt gets stickier after the first shot or two when working up loads that are near max?

 

[muleman69]

I absolutely agree that the shooter is a huge factor in the accuracy equation! Interesting that there isn’t much discussion about it in the various forum threads that seem to focus primarily on technical aspects. How could we get such a thread started... hmmmm?

Sounds like a great thread (human errors at the bench)? Get one started ,I'm all ears

 

[jim_k]

I have searched and can't seem to find any info.
Here is the deal-
I have a Savage BVFS in 22-250. I have have had it for several years. My problem is that I work up loads and invariably it shoots pretty good on the final groups.
So then I think I have a good load. Then when I shoot it again later the groups open up.
This has confused me for a long time. What I have learned is the it only shoots good when the barrel is hot. When the barrel is hot it will shoot 1/2 inch. When the barrel is cool it shoots 2 inches.
Thinking it was a bedding problem I bedded the action, I did it myself so maybe I did not do a good job but it still only shoots good when the barrel is heated. I have tried every combination I can think of when it comes to bullet and powder combinations and seating variations.
So now I am thinking 2 things-
1. Re-bed the action and see if that fixes it.
2. Put a new barrel on it.

Can anyone shed some light on this conundrum?

Barrels often require 5-10 shots before they are "ready". At F-class matches, strings are 20 shots. On the first relay of the day, unlimited sighters are allowed, and many of the best shooters fire 7-8 sighters, seemingly no matter what the scores are (assuming they are all at least in the 10 ring after slight adjustment). Then they fire their 20 shot string just about as fast as they can, something like one shot every 20-30 seconds for the string. OK, you say, these are straight tube barrels, and aren't affected by heat. So I took my 22" Savage hunting rifle and shot 20 shots like it was an F-class match. The group was 1.74" at 100 yards, but 3 of the shots were not in the main part of the group. The big hole in the middle measured 0.96" for 17 of the 20 shots. The 3 were shots 1, 14, and 17, for what that matters. Take whatever you are shooting, and shoot a 20 shot group, without any intentional time to "cool down" between shots. Only then will you know what is going on. I bet the group is 1-1.5" center-to-center. Report back.

 

[JFrank]

How should a person bed in front of lug as a rule?

Personally
I find no need to bed in front of a lug, only the action ( when bedding at all)
Experts may disagree and that’s fine also
J

 

[Bojo]

Maybe a scope issue ?
I shoot a 12fv factory 1:12
36.0 varget , 40 grain barbest pn#22429
cci200 winchester brass.
Very impressive load to say the least in my rifle.