@ 08:06 am (GMT)
Thomas Kitchenhi bert
after reading your post i done a little bit of research as i was wondering if the ctr bottom metal could be modify for the trg42 magazine for the magnum tikkas, don't think its possible.
how ever came across these http://www.atlasworxs.com/cart/index.php?act=viewProd&productId=11 its bottom metal that will accept the accuracy internal mags which may be a cheaper option.
one of the forum members used one of there straight replacement ones that accept the standard tikka mags on his rifle. it may be worth a read for you http://www.ballisticstudies.com/Resources/Discussion+Forums/x_forum/17/page/3/search//thread/3925.html
hopefully i haven't confused you more about your build.
Nathan if you read this they also do one to accept the magnum length aic mags not sure on c.o.a.l of magazine yet thou