6mm Dasher Comparators

[FNG1001]

I'll be running an Impact 737r with Prefit barrels and 6mm Dasher Alpha brass.

Question is: which size SAC comparator to use? Looking at the product page, 3 variations are supported:

1. 6mm x 40° .275” Neck, .060” Neck Shoulder Radius
2. 6mm x 40° 273” Neck, .060” Neck Shoulder Radius
3. Alpha 6mm Dasher (Alpha Legacy Reamed Chamber)

Will be using Forster 6mm Dasher FL sizing die (stem removed) + 0.002 mandrel.

The dimensions of the brass listed are:

I.D. .241" O.D. .2675" Loaded Diameter .269" Dia. Tolerance +/- .0005

 

[TheOfficeT-Rex]

Depends on the reamer, not the brass. You’ll probably be fine with the 275 neck.

 

[Mordamer]

Option 3

 

[FNG1001]

Depends on the reamer, not the brass. You’ll probably be fine with the 275 neck.

Thanks! I forgot to look at the reamer specs used on the prefits.

Im assuming for the ones listed as, would imply i need at least the 0.275" neck diameter:
.274 Neck Dia. and .135 Freebore

Im not sure what specs the Alpha Legacy reamer uses.

 

[Mordamer]

Thanks! I forgot to look at the reamer specs used on the prefits.

Im assuming for the ones listed as, would imply i need at least the 0.275" neck diameter:
.274 Neck Dia. and .135 Freebore

Im not sure what specs the Alpha Legacy reamer uses.

The Alpha comparator would work on brass that came out of a normal Dasher chamber or an Alpha reamed chamber which is why I recommended it.

 

[TylerN]

I have the .273 x 40 and the Alpha comparator and they both work the same for me. And I'd expect the .275 would also do exactly the same.

 

[FNG1001]

I have the .273 x 40 and the Alpha comparator and they both work the same for me. And I'd expect the .275 would also do exactly the same.

it took me a while to find the reamer specs, but i think the 0.275 would grab more of the shoulder, make it more reliable reading than the 0.273.

 

[9/11]

it took me a while to find the reamer specs, but i think the 0.275 would grab more of the shoulder, make it more reliable reading than the 0.273.

Me personally don't believe that it's a good idea to chamber my gun to brass it's easy to shaper the brass to my gun