Mongorestore fails for large(ish) collection in Meteor 1.0.4.1 / MongoDB 2.6

I’m having a problem mongorestoreing data to a local dev server in Meteor 1.0.4.1. The collection in question is large, but by no means vast: 274MB bson, 35k docs.

Immediately after a meteor reset, in Meteor 1.0.3.2 / MongoDB 2.4 I get:

Fri Mar 20 16:41:47.222 ./updates.bson
Fri Mar 20 16:41:47.222 going into namespace [meteor.updates]
Fri Mar 20 16:41:47.274 warning: Restoring to meteor.updates without dropping. Restored data will be inserted without raising errors; check your server log
Fri Mar 20 16:41:50.087 Progress: 80179407/274368881 29% (bytes)
Fri Mar 20 16:41:53.143 Progress: 163031299/274368881 59% (bytes)
Fri Mar 20 16:41:56.075 Progress: 245155299/274368881 89% (bytes)
34479 objects found
Fri Mar 20 16:41:57.800 Creating index: { key: { _id: 1 }, name: “id”, ns: “meteor.updates” }

But if I meteor reset and upgrade to Meteor 1.0.4.1 / MongoDB 2.6 before doing the same I get:

Fri Mar 20 16:39:11.764 ./updates.bson
Fri Mar 20 16:39:11.764 going into namespace [meteor.updates]
Fri Mar 20 16:39:11.770 warning: Restoring to meteor.updates without dropping. Restored data will be inserted without raising errors; check your server log
Fri Mar 20 16:39:14.128 Progress: 72011103/274368881 26% (bytes)
Fri Mar 20 16:39:17.011 Progress: 148000775/274368881 53% (bytes)
Fri Mar 20 16:39:20.137 Progress: 233232012/274368881 85% (bytes)
Fri Mar 20 16:39:20.242 Socket say send() errno:104 Connection reset by peer 127.0.0.1:3001
assertion: 9001 socket exception [SEND_ERROR] server [127.0.0.1:3001]

Can anybody with more experience of MongoDB than I have advise why this could be? I don’t seem to be anywhere near the limits listed here.

Thanks