Loading the 77 Sierra TMK

[YZ-80]

Guys,

I'm resurrecting a load I had with Ramshot TAC 5 years ago but the problem is, I ain't got no TAC. It shot well out of my 1:8 20" heavy barrel on 23.4 grains but now all I got to work with is Varget and RL-15. I'm embarrassed to say that I don't know the speed from the old TAC charge. Anyway, I'm dealing with Starline .223 brass. I got a Wylde chamber but I can't load it to 5.56 pressure with .223 brass, can I?

I'll load check charges down low but assuming acceptable accuracy, what is a good speed to target for this bullet if I want to shoot deer at 200-250 yards? I have a magnetospeed now. Can I achieve these velocities with Varget or RL-15? Any

advice is appreciated.

 

[xsn10s]

That's a tough question. Starline states that their 5.56 brass is harder than their .223 Rem brass. But if their .223 rem brass is loaded to 5.56 pressures then use them only in 5.56 rifles. I loaded the 77 SMK to 2750 fps in a 20" AR15. My current TAC load with the 75 ELDM is right around 2700 fps. Even if your load was only going 2625 fps the impact at 250 yards would be around 2100 fps. More than enough to reliably expand.

 

[YZ-80]

That's a tough question. Starline states that their 5.56 brass is harder than their .223 Rem brass. But if their .223 rem brass is loaded to 5.56 pressures then use them only in 5.56 rifles. I loaded the 77 SMK to 2750 fps in a 20" AR15. My current TAC load with the 75 ELDM is right around 2700 fps. Even if your load was only going 2625 fps the impact at 250 yards would be around 2100 fps. More than enough to reliably expand.

Thanks. I think I can do that with the powder I have on hand. Varget works really well with the 60 grain V-Max, where I'm getting about 2,840 out of 24.7 grains. Very accurate and I have plenty of it.

 

[lancetkenyon]

The 77TMKs are awesome.
Varget works great in my 24" AR pushing 69SMKs to 3033fps.

 

[YZ-80]

The 77TMKs are awesome.
Varget works great in my 24" AR pushing 69SMKs to 3033fps.

Wow. That sounds good. What charge weight and are you running it as a 5.56 or .223?

 

[Pdyson]

23g of Varget works great in my 223 Wylde AR. I'm using Starline brass and Fed 205 match AR primers with No pressure signs Benchmark and H4895 are almost as good as Varget.

 

[lancetkenyon]

Wow. That sounds good. What charge weight and are you running it as a 5.56 or .223?

.223 Wylde chamber, using LC brass. But running it about 1gr below max.

 

[Dirtrax]

Varget runs much slower with 77's in my rifles. None of them bolt actions. This is a general statement and be advised that it may not work in your rifle but it seems 24grs of just about anything works well with this grain weight bullet in a wylde chamber. You won't get 3000+ fps though. I run 24.1grs of 8208 in the 2800fps range in an 18" barreled at-15. Tac meets MK-262 specs at 24.5grs. I run slightly lower than that and it eats brass pretty quickly. I have a springco "white?" spring, adjustable gas block, and a light weight bcg. It runs like butter.