The Tikka bolt shroud serves no purpose other then to cover the bolt cocking piece. Gas would be diverted thru the magazine well in the case of a failure.
That's wishful thinking. If all the gases came through the firing pin hole, they would vent out the holes in the bottom of the bolt into the magazine. However it doesn't all come through the firing pin hole, they will also vent on either side of the locking lugs. On the right side they will come out though the locking lug raceway on that side. On the left side some will vent out the hole on that side of the action, but because the gas from a pierced primer or blown case head is pretty intense, and since it will follow the laws of physics, and not want to make a nice clean 90 degree turn to vent out the hole, some will continue in its original rearward direction of travel back through the left hand side raceway. Because the bolt is completely enclosed on that side by the receiver it can't vent anywhere but at the very end where it meets the plastic bolt shroud. If it is cracked, well guess what, you're getting it in the face. Here are links describing this exact situation:
https://www.snipercentral.com/forums...7092367dcc0351http://www.canadiangunnutz.com/forum...ud#post1523241http://www.canadiangunnutz.com/forum/showthread.php?t=399356There may even be some on this board.
Mauser type actions have a space on the side of the left receiver wall, whether it is the stripper clip cut out, or the small space like on the top left rear of the Ruger 77 receiver wall that will let some gas escape. They all have a nice solid steel flange on the shroud to defelect the gases that do reach the end of the left side raceway away from the shooters face. Another thing to keep in mind is that the shroud on the T-3 fits inside the receiver, making the gap for the gas to escape even smaller. In the event of gases coming down the left side, this means they are further compressed before they can escape (like putting your thumb over the end of a garden hose).
It seems all the Tikka guys are in denial about this, and want to keeping asking the same question until someone says "Yes don't worry that plastic piece that is prone to breaking off, and has actually hit shooters in the eye, it will be fine on your rifle, so don't worry about it."
If you check at the very end of the linked thread, you'll find a company in Australia that manufactures alloy shrouds, that should offer better protection.
Hinterland Shooting Supplies Pty Ltd
Richard Garwood / Fiona Parker
Phone / Fax: (07) 5455 6925
Mobile: 042 787 6817
Email: info
hss.net.au
PO Box 807, Tewantin, Queensland, 4565, Australia.
ABN: 60 115 465 588
And here are the pics they sent me of their shroud:
http://s225.photobucket.com/albums/dd93/Richardoz1971/shroud/
