But the question is which metal mag? Accurate mag offers one already set for 308 feed lips. But their follower sucks and wobbles all over because the follower isn’t CIP length. Perhaps a magnum magazine with feed lip adjustments from a place like MDT might be better.
As it stands, the market offerings (including follower/spring/spacer kits) for multi-caliber setups with long actions and CIP chassis/bottom metal is virtually non-existent and there is tons of room for improvement with magazine reliability. That said, I realize the market itself is rather small because half the small group of people interested are probably going with Barrett, AI, or Cadex anyway.
But once I have some spare time I’m planning to draw up a 3D model for a spacer for the 308 CIP accurate mag. It will just require trimming the follower back towards the spring and some test and analysis for the angle/height of a slight ramp built into the spacer.
I’m also going to look into an external front spacer for the Magpul 30-06 mag with a built in very very slight ramp that overlaps with the top of the front of the mag. I’m much less confident about that one, but will likely try it still.
What purpose would the spacer serve? Just a little food for thought:
I made a spacer kit for AW and AICS for a number of years and offered it for sale. The AICS kit was a spring, follower, and spacer and it had enough clever engineering in it that we got 2 utility patents issued on it. There was a cheap knockoff that pervaded the market because it was cheap and they were sold as a 3D printed product for a while before MDT basically copied that one and brought it to market in a turn key setup. We still sold several thousand kits based on the number of springs that I have ordered over the years.
The AW kit was resoundingly simple, it was just a spacer that used the factory flat spring and a trimmed follower to run Dasher and BR cartridges in the body. Anyone with a dremel, razor, or hacksaw could modify it. However, since it required modification of the factory follower and that modification was not reversible virtually nobody bought them even at $10 for the spacer due to not being able to turn the mag back into a standard setup.
On a long action there was no necessity in any of my personal rifles or rifles built for customers to require a spacer to properly feed 308's in a long action. It also works fine for Mausers and Tikkas as well as internal boxes. It was just needed for the super short Dashers and Grendel case bodies.
I think it was Cadex and AI that both offered a setup to change the bolt stop position and swap in a spacer for LA chassis to be able to run SA mags in a LA for swap barrel setups. Maybe Sako did as well, I don't recall for sure now. Perhaps you see a niche product slot that we didn't identify back in 2015 and 2016 when the development and patent work was being done.
