Any suggestions ?

Don't load hunting ammo to jam the lands would be worth considering.

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OHHH!!!!!!!!!!!!!!!!!!!! YEA, that lesson learnt in one season.
I loaded a batch and went hunting with it a few times, had a issue, thought it a once off, happened again and only then figured the cause. I am convinced the batch of reloads grew a few though in storage or when out in heat of day. They were touching the lands, perhaps, perhaps not, the words jammed are a over statement, (sorry, descriptive)but they had no jump, they were right there on the lands.
Never loaded like that since that hunt and loosing a kudu.

For your mate to have achieved what he did for the reasons you've speculated I can see no other description of what he would have needed to do than 'jamming the lands'. Pulling a bullet requires significant clamping force which I don't believe you could achieve with a bullet just kissing them. 

Any suggestions ?

Don't load hunting ammo to jam the lands would be worth considering.

*****************************
OHHH!!!!!!!!!!!!!!!!!!!! YEA, that lesson learnt in one season.
I loaded a batch and went hunting with it a few times, had a issue, thought it a once off, happened again and only then figured the cause. I am convinced the batch of reloads grew a few though in storage or when out in heat of day. They were touching the lands, perhaps, perhaps not, the words jammed are a over statement, (sorry, descriptive)but they had no jump, they were right there on the lands.
Never loaded like that since that hunt and loosing a kudu.

For your mate to have achieved what he did for the reasons you've speculated I can see no other description of what he would have needed to do than 'jamming the lands'. Pulling a bullet requires significant clamping force which I don't believe you could achieve with a bullet just kissing them. 

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Interesting !, Ya I would have to agree, whether I like to admit it or not.