I got all my dads guns when he passed away in 2003 and several of them are custom mausers that he built and I dont know for sure the specs. on them and the storys about how and why he built them the way he did. Tonight I decided to load up some rounds for a heavy barreled .243 that I remember being a real tack driver when I was a kid. The other day I picked up some 105 gr. Bergers and am hoping that they shoot well in this gun even though I'm not sure of the twist rate. I like seating my Berger bullets right at the lands and that was my plan for this load, however when I made my dummy round that I use to determine overall cartridge length I never could get the bullet to reach the lands. This perplexes me. Can anyone give me a reason for what would be different from "standard" about my chamber to cause this? Is it throated/freebored oddly for some reason? Like I said I vividly remember shooting the gun as a teen and it was very accurite, so I have a problem beliving that it has a headspace issue or anything else that would make it unsafe to shoot. If there is some possible reason for this, then how should I determine an overall cartridge length? Thanks in advance for any help/advice.