BBK-01 Ultramag action

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10 February 2004, 07:43

Mauser

BBK-01 Ultramag action

How much work does it take to turn this action into a 500 A-Square? Don't want anything fancy, just a plain jane field grade reliable rifle. Saw one on Gunbroker and thinking about getting it for a big bore project. Thanks!

10 February 2004, 15:08

476NE

I got one about 3 months ago for a 500 Jeffery project. Looks like it needs some polishing and some line straightening. Trigger pull is very good and it can be adjusted better. Other than that it looks like it will be an easy go.

10 February 2004, 16:44

500grains

476 NE, please be aware of two potential problems:

1. The bolt shroud is pinned, not screwed on. You may want to get one screwed on for safety reasons.

2. On some of these, the bolt could be opened so far that the bolt would not pull rearward. Double check yours. If it has that problem, the steel can be built up via welding then machined to solve the problem.

11 February 2004, 02:12

Mauser

Thanks for the info guys! Man it sounds like this action has a very lousy bolt assembly setup. The reason I am considering this action mainly because it has a Winchester style 3-position and I also like the Timney trigger. Does anyone have a picture to show the bolt shroud assembly?

Quote:

476 NE, please be aware of two potential problems:

1. The bolt shroud is pinned, not screwed on. You may want to get one screwed on for safety reasons.

2. On some of these, the bolt could be opened so far that the bolt would not pull rearward. Double check yours. If it has that problem, the steel can be built up via welding then machined to solve the problem.

11 February 2004, 07:37

476NE

Thanks 500grains for your erudite input. The action does not appear to suffer from the bolt opening too far. I think it wise, as you suggest, to screw the bolt shroud.

11 February 2004, 11:07

476NE

Here is a pic of the shroud.

11 February 2004, 11:10

Mauser

Thanks for showing the picture of the shroud but could you take the bolt-shroud assembly apart and show us how they are pinned together if possible? Very nice digital picture bu the way!

11 February 2004, 11:19

476NE

Sorry but I probably couldnt get it back together again.

11 February 2004, 12:42

Stryker225

What's the bolt face diameter on these?

11 February 2004, 14:50

476NE

Looks like .605 where machined and a total bolt diameter of .730