What is causing this?? .243 load

[btm_54]

I use a RCBS Charge Master for my powder measure/dispenser. So yes..every charge is measured. Bullets are 107 SMK's...rifle is a .243 with a 1:7.5 twist.

The rifle is a chassis type so no bedding.


Take care,Stan

With the RCBS Charge Master I noticed the machine was a lot more consistent with changing the power supply to a battery, a large one ). Where I live the power supply goes up and down in random patterns all the time and removing the inconsistency in power supply made the Charge Master results more accurate, when I weighed the loads to check) and repeatable.
The quality of the power supply affected the machines performance.

 

[BIGGUNGOBOOM]

Stupid question, but has the rifle been bedded and has the barrel been floated????? I had a similar issue with a 308 police and the barrel got warm and started getting pinched by the stock. so I floated the barrel and bedded the action and have never had the problem again.

 

[Winchester69]

The best groups seem to be with the bullets right in the lands...not sure if I should try seating them deeper in the lands??
Right now I can open the bolt and remove the round without it pulling the bullet out of the case. Would you suggest jamming as my next step?

Bullets seated to the lands will be both in the lands and out of the lands due to variation in ogive shape. To get consistency, some jamming is necessary. Not a lot; just enough to ensure being consistently in the lands.

If you haven't already done so, you might also inspect your barrel's crown. Lightly drag a Q-Tip around the edge of the bore; you're looking for a burr that would catch the cotton.