New Build .300 Win Mag Question on cartridge length


Active Member
Nov 17, 2003
Houston, TX
I'm getting ready to build a .300 win mag using a rem 700 action. I want to be able to shoot the high BC VLD type bullets 190-210 grain. How long is the overall cartridge length with these type bullets and do I need to use a bigger magazine box like a Wyatt's to accomodate the longer cartridge length


You should be fine. I shoot the 215 hybrids .013 off the lands with a customized rem 700, and they fit in my magazine. I've read of other people on here too that have been able to put the 210 vld's just off, or just touching, with no clearance issues.

You said you want to shoot the high BC VLD. Why not use the seating depth friendly higher BC hybrid? 215 target hybrid BC is .696 vs 210 VLD .631 If you choose to use the hybrid you might be able to seat the bullet to fit your standard magazine and still shoot accurately with a jump to rifling. I have loaded many hybrids. Longest two jumps are .065" (6mm 105 hybrid target, 6mm-284) and .140" (230 gr hybrid target, 300 WSM)

If it is because you want a hunting bullet no need to worry the 215 target hybrid has been proven to do just fine. Broz has done quite well this year.(see link below)

This thread called 210 VLD vs 215 hybrid should be all you need to know:
So it sounds like I don't need an extended mag box for the 215s, but I might for some of the other longer bullets? Does anyone have actual measurment from base to tip of bullet for the 210s and 215?
It is your choice. Depends on if you want to touch the rifling, if possible, or get need to get the bullet closer to the rifling. I'd say load a dummy round and do some measurements. Maybe work up some loads and see if it will shoot.

Wyatt's mag box does require some minor machining. Have done it with a dremel tool in two SA rem 700s but it was slow going. I'd also say that you could have issues with feeding, might need a different follower or perhaps some ramp work if you seat bullets longer, you never know.

I just suggested you try the factory magazine arrangement with a hybrid and if it doesn't work to your satisfaction get the Wyatt's mag box. I have one on my post 64 model 70 for a 300 RUM when I used to shoot accubonds. It feeds just fine with original follower. Can't say the same for my 6mm-284 in a SA Rem 700, need to do some changing to make it perfect.
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