[Mike402]

I've got a A1 that I'm thinking about upgrading to the TBM system. Question - are the mags the same size as the 4 rounder DBMs in terms of cartridge COL allowance? I've looked everywhere and can't find an answer to this.

It would be nice if I could seat bullets a little longer, rather than be limited to 2.8"

 

[trigger643]

I have no personal experience with the DBMs. I am using the TBM. The internal length of the magazine is 2.88". I am loading to a COAL of 2.86"

 

[djv38]

I've been loading to 2.800" OAL with the 4 round DBM's and there's a little room to spare. If I remember, I'll measure one later today for you.

 

[djv38]

Internal length of my DBM's are 2.900"

 

[Mike402]

Ok great thanks. I just ordered the TBM system through Midway with a spare 10 rounder. I've been getting by with two loads - a 2.800 COL 168gr that fits my current 4 round DBM, and a 2.950 COL 178gr long range/accuracy round that I single load.

I am going to run an OCW at 2.85 with the 178s and see where that gets me.

 

[trigger643]

It was a happy accident with my build that the best load I've found is 0.075" off lands. I'd not considered the limitations of COAL by the magazine, but using 105g Bergers it worked out (mine's chambered for .243AI).