Need help with mini 14, 6mmx223, 87 gr. V Max Load.

[shadeecatsunee2]

12/16/07--Sunday

Hello,

Had a 1x24" 6mm, 1:8 bull barrel, put on a mini 14 platform.

Need help choosing a safe starting load for 6x45 [6mm-223]to shoot 87 gr. V Max bullets. Has anyone tried this bullet in 6mm-223 brass? The usable case capacity for 6mm-223 is given as 1.87 cc.

Page 256 of the Lee second edition manual indicates a COL of 2.350 inches for both 85 and 90 gr. jacketed bullet 6mm-223 loads.

But the ruger factory magazines will accept a COL of 2.267 inches. Which is an .083 inch deeper seating depth than in the Lee manual's 85 and 90 grain listed loads on page 256.

Hoping to shoot the 87 gr. V Max bullet in this gun even though
shorter COL changes pressure and free bore.

Thinking to try H335, H322 and H4198 powders to develop.

Question:

Is there a formula for a safe beginning minimum powder charge, for one or more of the powders listed above ... that you would suggest to start out with?

Thank you very much.

 

[JDJones]

I have a 14.5" barreled AR that I use 75gr bullets in and the best powder I have found is W-748, I do have to seat the bullets deeper that I'd like but that the penilty for using the AR platform and in your case the mini14. The round is very good an realy beefs up the performance of these rifles I personaly think this is the direction that the government should have gone when exploring new ideas to replace the 5.56 NATO
You should be able to get the pressures up a little higher in the mini-14 that I can in the AR due to you having the btter gas system.

the biggest thing is that just start at the recomend starting range and work up fom their with your seating depth, you will liely find that you will hit higher pressure faster than the book list

 

[24kshooter]

Check with the folks at Accuracy Int'l. They know as much about mini mods as anyone. http://www.accuracysystemsinc.com/index.php
The main problem I see is the degree to which you have decreased the volume of the case and how high the pressures will increase. Similar to mil spec 5.56 x 45 brass vs commercial 223 REM - standard issue. Several other factors to consider - such as barrel chamber dimensions,, brass mfg., powder burn rate, bullet weight and so forth. Your 1:8 twist is pretty aggressive for a 6 mm bullet and it will be interesting to see how your accuracy works out. 1:10 for heavier or 1:12 for lighter under 90 gr. bullets would be more typical.