problems with heat

[browning525]

I have an addiction to the larger caliber rifles. (My smallest gun in the cabinet is now the 350 rem mag) My problem as of late, is that the first two shots out of the barrel with these cannons, shows all the potential to be a fantastic group, and then the third shot will go two or three inches high. These shots are taken in the recent heat-wave (30degrees plus). By the third shot, the barrel is definitely hot (actually TOO hot ) to the touch.
Has anyone else experienced this problem with the large caliber (or any)rifles. Is this a heat issue, or do you think something in my reloads or rifle?
Incidently, the last two rifles that I am working up loads for are the .358 norma mag, and the 340 wby. Both loads are below maximum listings in the reloading manuals.
Any thouhgts?

 

[H4831]

I have an addiction to the larger caliber rifles. (My smallest gun in the cabinet is now the 350 rem mag) My problem as of late, is that the first two shots out of the barrel with these cannons, shows all the potential to be a fantastic group, and then the third shot will go two or three inches high. These shots are taken in the recent heat-wave (30degrees plus). By the third shot, the barrel is definitely hot (actually TOO hot ) to the touch.
Has anyone else experienced this problem with the large caliber (or any)rifles. Is this a heat issue, or do you think something in my reloads or rifle?
Incidently, the last two rifles that I am working up loads for are the .358 norma mag, and the 340 wby. Both loads are below maximum listings in the reloading manuals.
Any thouhgts?

Very common with any centre fire rifle. A rimfire also, only it takes a lot more shooting to get the barrel warm.
Your rifle needs to be bedded. Free floating of the barrel may help, but proper bedding of the action and a bit of pressure on the forend of the barrel will likely result in the best five, or ten shot groups.

 

[iceman2]

Are the first shots out of a clean barrel? Sometimes POI changes once barrel is fouled. Just something else to check.

 

[browning525]

heat issues

Once the barrel is broken in, I only clean the gun before putting it away at the end of the season.
I have been shooting the larger calibers (350-416) for years with little notice of flyers to this extreme. I also, as a general rule, take 3or 4 guns to the range at a time, so they have time to cool off between groups. The last few times have been the exception to this (only taking one at a time) and that is why I am wondering if I am trying to shoot too many rounds through a hot barrel.
And yes, the action is bedded and the barrel free-floated.

 

[cosmic]

You should try letting the barrel cool down .. it usually takes a shot or two two get things warmed up, then you've got to let some time pass between shots. Use your hand as an indicator - try to keep the barrel temp the same between shots.