Gun powder help 77gr Sierra MatchKing.

[Tech4]

I am using 55gr and want to develop a load for 77gr Sierra MatchKing for my 5.56x45. I will be using it for long range and have a 16" barrel. I was wondering what powder or powders I should try.

 

[brentc]

8208 XBR and Varget are a couple of solid temp stable choices. RL15 if you can deal with a little temp sensitivity.

 

[xsn10s]

I had good results with TAC and H4895.

 

[sable tireur]

Well, the stupid upgrade destroyed my post and the information I was supplying. What a joke to upgrade first thing in the morning while people are checking the forums.

Will this load be magazine fed or single shot? I'm guessing magazine since you're using that short barrel.

Twist rate? Have you checked to be sure the twist is enough to handle this bullet?

Define long range since a magazine length combination will run out of steam (subsonic) before 1,000 yards.

You can entertain using:

VVN-530
IMR-3031 (don't laugh, this is a superb powder for this combination)
AR-Comp
8208

 

[User4302021]

23 grains of anything medium burn rate is a good start

 

[YZ-80]

Another vote for Ramshot TAC here!

 

[Wingnut00]

H-322. Start at 21 grains and work up. 2.250 oal with a 450 magnum primer. 22.3gr is my load with 77's.

 

[johnnyk]

Straight from Hodgdon Reloading Data Center; heavy bullet load: CFE 223, Varget, IMR 4895, IMR 8208 XBR and BL-C(2).

 

[Kansaswoodguy]

8208 you should find a node around book max I shoot the hornady 75's or those 77's to 1000yds out of a 24" AR

 

[Dirtrax]

8208 xbr for 5.56 wylde. 2800 fps w/77's out of an 18" barrel. 1/7 twist and 1/2 moa to 600yds loaded mag length.

 

[TRG65]

As noted before, 23 grs is a good place to start. I'm running 23 grs of Varget with the 77 at mag length for an AR. I'm getting an average of 2540 from an 18" barrel. The velocity isn't anything to write home about and I'm using range brass, so I'm getting a miserable SD, but it will shoot a consistent sub-MOA for me and this was the only load I could get below 1.5 MOA

 

[RT2506]

The biggest problem you will have is to FIND SOME IMR 8208 or Varget. LOL Seems to be sold out EVERYPLACE.

 

[Matt Tatum]

My go to load is 23.0 of IMR 8208 xbr. Works great in all my auto's

 

[DavidleeCole]

I love CFE 223 with my 77 SMK 23.5gr. It shoot well at wag length and makes first round hits out to 440 yards on 10 plate every day no matter. I just have a 1×4 power scope so I have not went out past a quarter with it. Ont the terminal ballistics end I have killed 11 deer with this load taken two or more every year for the past 5. And the kids love it too. I shoot an AR with an 16" 1:7 twist and get 2540 fps.