338-416 Rigby IMP


Well-Known Member
Jun 12, 2001
Palmer, Alaska
I have come to understand there are several 338-416 Rigby IMP cartridges, I am courious as to what their differances are and which one are you using Darryl? Where may I purchase that reamer also? Thanks

Bruce Baer built mine which was the first 338/416 Rigby Imp that he built at that time.
He had the 33 Baer which was the same case dimensions only using a 378 belted Weatherby Case. He simply improved the 378 case to come up with the 33 Baer.
I didn't want a belted case and asked him to have a reamer made on the non-belted 416 Case and use the same overall diminsions.

I think JGS has that reamer.

If you want, I can send you a fired case and you can have your own reamer made off of mine.
Let me know.

Thanks Darryl, I'll email you about the case. Sounds like the sure fire way to go.

The JGS site has a 338/416 Brooks reamer, is this the one you have used?

With the 300gn Sierra what OAL do you use and how far off the lands are they? All the Weatherbys have quite a jump so I wonder if accuracy is being comprimised a bit to keep the PSI from spiking.

I loaded some .416 Wby 400gn Barnes XLC's to .030" off the lands and groups went from under .750" to 1.75". The bullet had to be seated out quite a ways so powder charge may have needed to be adjusted is all.

I never checked though, just figured they might all shoot in the same hole so I tried it once. Same thing with the 400 Swift also. Fun fun fun, $$$ testing is. Brent
does Bruce Baer have a web page.i have a .50 bmg made by mcbros its a light benchrest at 32.4 pounds its only so light.what would be the best for long range and still able to carry not far just carry some,thanks,keith
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