Hot barrel shot wandering

[J.flanagan]

My first rifle was a savage 10 fcp hs in 308. I had a great time learning to shoot with it. It was accurate and due to the heavy barrel, it seemed to heat up real slowly and stay accurate no matter how many shots I put through it. However, its a bit of a pig when it comes to weight. So, as I started to think about backcountry hunting, I decided to pick up a lighter weight rifle. I bought a Christensen Ridgeline in 6.5 prc and am overall, pretty happy with it. If I'm taking 3 shots at a time, its fantastic. I'm not the worlds greatest shooter but I can get quarter size groups at 100 yards most of the time. However, this past Saturday, I was shooting at 6" steel at 300yds and putting a lot more rounds through in a shorter time frame. After about 6 shots I began to miss wide left or right every other shot.

So, on a light weight barrel, either steel or carbon fiber, how much does a hot barrel affect your accuracy? Are we talking 1/4" at 100 yards or can it be way higher?

Also, I haven't bedded the stock, is that something I should learn to do?

 

[KenLee]

Probably as much you getting tired of being kicked as it was the barrel heating up.

 

[PathFinder]

There have been a lot of threads and debate on this topic, a search should help you take advantage of what has already been presented.
To summarize what the conclusions of those threads are:

• Good barrels don't wander, particularly in one direction or another. Not until they're way hotter than you'll ever get a hunting, bolt action barrel.
• Certain poor quality barrels can wander...yours is on that list. The barrel getting hot shouldn't be causing misses on a 2 MOA target in 6 shots.
• If you want hard data, shoot 10-15 shots on paper at 100 without cooling between.
• Proper free-float and bedding could help, but your Christensen is supposedly free floated and bedded.

If you can shoot on paper to get some hard data that would be very valuable, both for yourself and the forum. There's a lot more debate on this subject than there is actual data.

 

[wind gypsy]

How do you know it was left or right misses and not random in any given direction?

You'll find lots of opinions on the matter of barrel heat's impact on precision. Popular thought on this forum is that if a barrel is properly stress relieved precision should not significantly degrade with heat. How many barrels are properly stress relieved? hell if I know. In my opinion, wrapping a thin steel liner with carbon is another way that stresses could be induced in a barrel.

The other thing is that as a barrel heats up you get more mirage off the barrel and that can impact where you hold for POA. Mirage seems to be a bigger issue with carbon barrels than steel.

I don't think you'll get a conclusive answer based on the information provided. All you can do is test your gun in a manner that gives conclusive results.

 

[SloppyJ]

This is why most people's hunting rifles don't double as their target rifles. I believe that heat has a bigger impact on a hunting rifle than some believe on here. That's just me though. Personally, I don't lose any sleep over it because if I take more than 3 shots at one animal in that short of a time frame, I have bigger issues to worry about.

I test loads in three shot groups. Queue up the people saying: "OH MY GOD, shoot ten or you'll never know what kind of groups you're getting!" When I find a load I test it quite a bit. I'll shoot probably 20 or so rounds before I settle in and call it on a specific load. When it comes down to it, I mainly care about where that first round is going though.

With that said, If this is the path you want to go down, you need to replicate this on paper. In between strings of shots, take your bolt out and let the rifle cool down and test it again. See if it's consistent. Have you checked to see if your barrel is touching anywhere?

 

[Dmoua]

Are you using factory ammo or loading your own ammo? I have 3 rifles with Proof Carbon fiber Sendero light barrels chambered in 300Wsm, 6.5CM, and 6 Dasher. I have no issues with shots wandering when the barrels heat up with my own reloads. If I miss, more than likely I caused it.

If it’s a stable load, it’s likely that you’re getting fatigue after x amount of rounds.

 

[hereinaz]

When diagnosing issues like this, I am always considering whether it is the rifle or the shooter. Sometimes it is both. Even when I am the shooter, I try to control for my own errors and avoid self deception.

If you are controlling for your own possible erroneous inputs, then it could be the barrel. But, I agree that sometimes other issues are blamed on the barrel.

Regardless, I always go back to 100 yards and start over.

 

[ResearchinStuff]

so many potential causes, the barrel heating up is only one of them. need to test as wind gypsy laid out, and then you can start to piece together if it's the barrel, shooter, scope, mounts, bedding, barrel contact, or ammo.

 

[JohnJohnson]

Popular thought on this forum is that if a barrel is properly stress relieved precision should not significantly degrade with heat. How many barrels are properly stress relieved? hell if I know.

Christiansen uses button rifling for their barrels which does induce some stress that has to be relieved. It's a step up from the standard hammer forging that most factory guns get their rifling from and those do get affected by heat much more. Companies like Bartlein/Krieger use single point cut rifling to not induce the stress in the first place if I recall right. There are companies that produce some lights out button rifled barrels but I don't think Christiansen is one of them.