.223/77TMK for semi, results

[fedupflyer]

There's only one. Everything else is a 77 SMK. Just sayin'.

I am very well aware of that and that was why I am questioning the velocity.


My Black Hills 77 SMK do run about 30 FPS higher than Mk 262.

[Vegas]

For reference, I have got an average of 2760 out of an 18” WOA barrel with the 77SMK and XBR. That was in 90*F weather at about 3500ft above sea level.

[fedupflyer]

For reference, I have got an average of 2760 out of an 18” WOA barrel with the 77SMK and XBR. That was in 90*F weather at about 3500ft above sea level.

What is your load with XBR and what kind of groupings are you getting?

[Joker]

What other primers did you find you liked for 5.56 in that testing?

Federal AR Match have worked very well for me for several different calibers.

That's not to say a different primer is bad, just have to work up a load for it. I tend to stick with the SR magnums, bench rest or CCI 41s due to the fact I can push the loads a little hotter.

[Vegas]

What is your load with XBR and what kind of groupings are you getting?

22.9gr with a Rem 7 1/2 primer, typically at 2.255. At 100 yards, .7 and .8 MOA groups are common. I’ve had a few that were less than a half minute and more in the .6 range. Out at 400 and 500 yards, it groups around a minute but that’s likely more about me than the load. I’ve found XBR to be way more consistent than Varget for 77gr but have yet to try H322.

[mark5pt56]

Interesting, didn't know they existed.

https://www.federalpremium.com/reloa...-GM205MAR.html

Federal AR Match have worked very well for me for several different calibers.

That's not to say a different primer is bad, just have to work up a load for it. I tend to stick with the SR magnums, bench rest or CCI 41s due to the fact I can push the loads a little hotter.

[Joker]

What other primers did you find you liked for 5.56 in that testing?

Interesting, didn't know they existed.

https://www.federalpremium.com/reloa...-GM205MAR.html

Yep. I use them in several applications. .224 Valkyrie, .223, 6.5 creed (small primer pocket versions). They're a little thicker which allows me to push the load a little harder.

[mark5pt56]

I'm upgrading my rotary phone today-ordered a mandrel die and mandrels for .223 and 6.5. Since I have RCBS standard dies, I started by grinding the Eball down since it can't be moved without loosing decap. I need to get a decaping die and remove it altogether.

[markm]

I'm upgrading my rotary phone today-ordered a mandrel die and mandrels for .223 and 6.5. Since I have RCBS standard dies, I started by grinding the Eball down since it can't be moved without loosing decap. I need to get a decaping die and remove it altogether.

Yes. Decap is a must for any civilized loader. RCBS neck sizer is what I use to open the necks back up. I have a neck collet sizing die for .223, but the volume I do is too rough on it. They'll seize up and quit working correctly.

[Vegas]

I never really looked into mandrel dies and don’t know anything about them. What’s the advantages?