anyone have a good 77gr matchking load for an ar-15?

[fordwrench]

getting ready for pd season soon and i have 1000 77mk laying around. anyone have any good load combos for this bullet. i have a 1 in 8 twist armalite heavy barrel. been using rl 15 with 75 hornady bt. have had excellent luck with this combo but i would like to shoot up the 77s if i could. any opinions are welcome. thanks!

 

[1000yardstare]

Have a .223 F Class rifle, 30 inch 8 twist MacLennon barrel, Wylde chamber. Found RL15 a little too slow to get the velocities I wanted.

Switched to H4895 with the 77 gr Nosler Competitions. Load of 24.5 gr, Win brass, CCI 450s, chronos at 2950 fps. Very good results at 300 yards in F Class practise.

Went up to 25.0 gr H4895 but got slight cratering on the 450s so backed off to 24.5 gr.

 

[msnations]

2 grains of bullet weight won't make any perceptible difference in an AR- just use the same load of R15. Load should probably be around 24.0 grains...

-Mark

 

[HPMike800]

I just worked up a load for my daughters match rifle with H4895 and LC brass.

77SMK mag lengh - 22.5grs - 2725fps
80SMK long (0.045" off) - 23.2grs - 2790fps

 

[fordwrench]

Thanks guys for the info. I have both powders so ill give them both a shot.

 

[6BRLongRange]

23.5 - 24.0 of RL15 or Varget will work also. Start lower and work up to these loads as usual.

 

[cmillard]

aa 2520 is also another great choice for the 77s. i have been trying ramshot tac behind the 77s with so-so results. i believe that tac is a little too fast for the 77s. i am planning on doing more testing with 2520, as i have nice hits out to 891 yards with my long range ar-15 with aa2520, sie 77s and wolf srm primers.

 

[kentuckytroutbum]

aa 2520 is also another great choice for the 77s. i have been trying ramshot tac behind the 77s with so-so results. i believe that tac is a little too fast for the 77s. i am planning on doing more testing with 2520, as i have nice hits out to 891 yards with my long range ar-15 with aa2520, sie 77s and wolf srm primers.

+1 on AA 2520 for my AR in 75 to 80 gr. bullets. You might want to look at the Hornady 75 A-max or HPBT. My rifle shoots both of them equally well, and I can usually find them on-line.

Bill

 

[fordwrench]

Tried both the h4895 and 2520. They both shot cloverleaf size groups around 3/8 inch. The h4895 did it at 23.8 and at 24.2 grs. The aa2520 did it at 24.5 to 24.7 grs. There wasn't a clear winner of those charges or powders. Anyone have an opinion of which powder is better than the other? I didn't get to chrono the yet. Which powder should give the most speed here? Any opinions welcome!

 

[Klong]

I would think that the 2520 load you had would be the faster load and the dirtiest load. Try around 24.7 gr of varget. It is good to at least 600 yards in most AR's.

 

[fordwrench]

Will do. Thank you!

 

[cmillard]

wait a minute. 24.7 grains of varget with a 77 sierra? do you want to blow the rifle up. unless you are single loading the 77s and seating them out far, that is way to much varget for magazine depth. i have tried up to 24.0 varget at 2.255 with the 77s and that was as far as i wanted to take it.

 

[msnations]

wait a minute. 24.7 grains of varget with a 77 sierra? do you want to blow the rifle up

Well, maybe its not seriously dangerous, but it is over the top. Sierra's 24.0 grain max is a pretty good load. I can't see any good reason to exceed it.

-Mark

 

[Klong]

I would think that the 2520 load you had would be the faster load and the dirtiest load. Try around 24.7 gr of varget. It is good to at least 600 yards in most AR's.

Sorry, I should have stated the normal " safe in my rifle, work up slowly" . I have shot this load in six different rifles and seen it shot in lots more. It is a standard load used to shoot at 600 yards by many competitive shooters out of AR's. None have blown up.

 

[fordwrench]

klong thanks for the info. ive been reloading over 20 years and would never try any load without working up to it. besides my rifle may like a charge or two on my way worrking up that suits me. i had some varget for a different rifle and it wont be a problem to give it a try.

 

[Klong]

Let us know what you find!

 

[cmillard]

just got off the range and tested the 77 bergers that i just picked up. loaded up 2 rounds of each powder charge. load 1-Lake City brass, 24.4 aa2520, 77 berger @ 2.255, wolf smr. load 2- Lake City, 24.6 aa2520, 77 berger @ 2.255, wolf srm. load 3-Lake City, 24.8 aa2520, 77 berger @ 2.255, wolf srm. THESE LOADS WERE SAFE IN MY RIFLE, WORK UP! Barrel--18" douglas 7" twist. Load 1--2 shot avg. velocity 2737 fps with nice round primer. Load 2--2 shot avg. velocity 2796 fps with nice round primer. Load 3--2 shot avg. velocity 2824 fps nice round primer, but with very slight ejector mark. i will work with the last two loads as the bullet holes on the target were very close. need to work on my neck tension a little so i can get a little more velocity consistency, so i think i will trim the necks a hair so they are all the same. for those of you that like to chase velocity in the ar-15 with the heavy bullets, i think that aa 2520 is king. also to note, i shot some more of my berger 90 vlds out of the same barrel. 24.5 H-380 (compressed), wolf srm, 2.500. avg velocity for 5 shots ( i usually do 10 shot strings) was 2558 with excellant accuracy at 100 yards. if it wasnt for a flier that was about 1/8" high and to the left of the other 4 shots--probably the high velocity shot (2595 fps)--i would have had a 1/2" group. i am curious to try this load at extended ranges to see if it is still stable.

 

[fordwrench]

I had a chance to chrono my loads of aa2520 yesterday. The 77 smks win brass and cci 400s shot right at 2775. At near the same chrges as cmillard. I had a load window of .2 tenths before the accuracy opened up. I usually work charges off of my harrels culver measure in half click increments on small cases looking for accuracy nodes and watching pressure as I work up. I found that at 40.5 clicks and 41 click I had 3/8 groups. These loads were safe in my gun too. I did work them up until I saw pressure and I don't doubt that you could get more speed than what I had but that's were it wants to shoot. Also did a load work up with 69 smk and aa2520 and saw my best groups at 3050fps with no pressure. I am concerned a little on the powder fouling of this powder. I will be cking varget and h 4895 again for speed and cleaner burn. I bought 4 lbs of 2520 I hope I don't regret it ! I am also wondering about the the 2520 being sensitive to weather changes and or warm chamber vs cold. Has anyone had any issues with 2520 ?

 

[cmillard]

aa 2520 used to be a real popular powder at camp perry. i do not hear too much about aa 2520 anymore and that is unfortunate. yeah, it is dirty, but over the course of my shooting with aa 2520, it hasn't really caused any problems accuracy wise or function wise on my ar-15s. fordwrench, what length barrel are you shooting? by the way, you will not be disappointed with the 4 lbs you bought, you will wish you would have bought a couple 8 pounders. i would like to try the aa2520 behind the 90 vld bergers i have and see how that stands up against the h-380.

 

[Klong]

I have used up around 20 pounds of 2520 a few years back. It shot well enough , but after 88 rounds the bolts in my rifles (AR) were stiff when you pull the bolt and carrier out and work the bolt by hand. I also had a lot of carbon build up in the carrier. As long as you clean regularly it should work fine.

It has some advantages since it meters very consistently and I did not find a big issue with temperature between 80 degrees and 95 degrees, which most of our matches are shot at. It was a little tempermental with the 80 gr bullets, but worked well with 52gr thru 77gr bullets.

I was able to improve 600 yards scores with H4895, Varget, and VV540, so I switched.