6X45 versus. 6X47

[georgetwalkerjr]

I"m sending my Cooper M21V in .221 Fireball back to the factory to have it rebarreled. I've already got two .20vTs and am considering having it done in either 6X45 or 6X47. Could anyone give me some feedback on this issue, and perhaps point me towards more information? Many thanks. George

 

[sierra22]

I have a 6x45,6mm-223) and will recommend it over the 6x47 for one reason alone: Brass.

You'll get cheap/good 223 brass everywhere. I use Winchester brass and open them up using a Sinclair neck expander. It cost about $15 and is intended for use with their neck turning tool. No problem using the Redding die-set either, the Sinclair tool just works smoother.

Sierra Reloading manual has good data on the cartridge. I use Vit N130 myself, 70gr NBT in 3215 fps and 85-90'ish gr bullets inn 2700-2730 fps,24" barrel)

 

[chrisj]

Go for the 6x45. Absolutely....for the 1 main reason....Brass. Lots of it, lots of different manufacturers, LAPUA brass!!!
I have 6x45's and 6x45 Ackley. They both shoot sub 1/2 moa and bbl life is definately better than a 223. a 6x47 will give you about 100 fps more, but that is the only benefit as far as I know.

Chris

 

[georgetwalkerjr]

I shipped my Cooper M21 off to Montana this morning, and am going to have it rebarreled to 6X45. Thanks for the feedback.

George

 

[sierra22]

Good choice.
I use 70 and 85-90gr bullets in mine. The midweights doesn't seem to offer the lighter bullets' benefit of higher speed in varmint bullets or the punch of the heavier hunting bullets. Too light bullets is to me wasting the potential of the 6x45 and you might as well use a 223.

I have tried expensive Lapua brass. No gain with the heavy bullets, but the 70 grain gave about 100 fps more. Accuracy same in Winchester/ Lapua cases, about 0,4 MOA with best groups about 0,26 MOA. This in a lightweight hunting rifle.

 

[Jmwat49]

You should check with Cooper but in the 6BR they use a 14 - 1 twist and I would think it will probably be the barrel they use in your change. This twist will mean you will be best off with the lighter bullets. The 6BR Keyholes any thing with weight so be sure to check this out.

 

[Vartarg217]

I checked with them after sending it in, and yes they do use a 1-14 twist barrel. It should be ready by September 1....they've been a lot slower than I expected, and slower than they promised. Not a big deal, I guess....I've already got more guns than I have time to shoot. Would the 70-75gr bullets be best....based on your experience? That's what I was planning on....thanks. George