Struggling with 5.56

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bross412

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Aug 25, 2020
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#1
I need powder recommendations. I'm shooting 77smks out of an ar15. Barrel is 14.5 criterion core with a huxworks flow 5.56k can. I'm using CCI primers and lake City brass. All brass has been annealed.

I spoke to the guys at Sierra and they mentioned that n140, the powder I'm using, isn't good for a 14.5. what powder are you guys running?

It needs to be temperature stable because I'm shooting year-long outdoor matches and it needs to be obtainable. So h4895 is out lol.

Please help.
 
#3
bross412 said:
I need powder recommendations. I'm shooting 77smks out of an ar15. Barrel is 14.5 criterion core with a huxworks flow 5.56k can. I'm using CCI primers and lake City brass. All brass has been annealed.

I spoke to the guys at Sierra and they mentioned that n140, the powder I'm using, isn't good for a 14.5. what powder are you guys running?

It needs to be temperature stable because I'm shooting year-long outdoor matches and it needs to be obtainable. So h4895 is out lol.

Please help.
Click to expand...
Varget
 
#7
The best try with the 77 gr SMK in 5.56 would be H322 21.4 gr 99 % burnt 99.9 % fill in a 14.5" barrel Nato chamber. 2.260" COAL.

Next Benchmark 21.8 gr 96.8 % burnt 100% fill.
H4895 22.9 gr 95.3 % burnt 103.7 fill
Last Varget 23.4 gr 93.5% burnt 109% fill.

The powder nearest 100% burn has the best potential for lower velocity spreads in the chosen barrel length, giving less vertical at longer ranges.

So you'll have to work up, and I'd start with H322 and work up an accuracy load.
 
#8
bross412 said:
I need powder recommendations. I'm shooting 77smks out of an ar15. Barrel is 14.5 criterion core with a huxworks flow 5.56k can. I'm using CCI primers and lake City brass. All brass has been annealed.

I spoke to the guys at Sierra and they mentioned that n140, the powder I'm using, isn't good for a 14.5. what powder are you guys running?

It needs to be temperature stable because I'm shooting year-long outdoor matches and it needs to be obtainable. So h4895 is out lol.

Please help.
Click to expand...

N140 is good stuff for 77smk try 23-24gr and 2.250" no reason not to use it

TAC is my favorite for price/easy to find/easy to get it in the case since it's ball powder but it's not as accurate as varget
 
#9
45-90 said:
The best try with the 77 gr SMK in 5.56 would be H322 21.4 gr 99 % burnt 99.9 % fill in a 14.5" barrel Nato chamber. 2.260" COAL.

Next Benchmark 21.8 gr 96.8 % burnt 100% fill.
H4895 22.9 gr 95.3 % burnt 103.7 fill
Last Varget 23.4 gr 93.5% burnt 109% fill.

The powder nearest 100% burn has the best potential for lower velocity spreads in the chosen barrel length, giving less vertical at longer ranges.

So you'll have to work up, and I'd start with H322 and work up an accuracy load.
Click to expand...
are any of these compressed loads? I am having a hard time with the n140 getting a consistent CBTO because of the compressed powder. A buddy of mine has benchmark, so i may swing up by his place to try it out.
 
#10
BCP said:
N140 is good stuff for 77smk try 23-24gr and 2.250" no reason not to use it

TAC is my favorite for price/easy to find/easy to get it in the case since it's ball powder but it's not as accurate as varget
Click to expand...
The guy at sierra told me that there was a lot of unburnt powder and that will pile up in my supressor and could cause an issue. I like the n140 but im also having trouble getting a consistent CBTO since its compressed. I have a 9 inch (3 area 419 stacked up) drop tube and have used a vibrating toothbrush, but still get very inconsistent cbto. Do you have issues with this?
 
#12
BobinNC said:
Temp stable and available direct from Hodgdon right now and all can produce similar velocities:

H322
Benchmark
H4895
Varget

Hodgdon Powder

I would think Benchmark might be the best for your application. Yes, the prices suck, but it is what it is....
Click to expand...
I am going to try out some benchmark. I have seen good results on youtube with 22gr. of course ill work up to it.
 
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#13
Varget, N140,RL15 are all going to be about the same. They will be compressed with a 77 or 69 SMK. You could roll or taper crimp.

Not sure what size target you’re shooting but I’m taking my 14.5s to 500+ routinely on full sized IPSC steel. They hold good elevation, wind can be challenging if it’s honkin’ but under 10 mph full value it’s a simple hold.

If it was attainable, I’d say H4895 but apparently someone decided we don’t need that shit anymore. AR Comp might work too but be careful with that shit.
 
#14
bross412 said:
The guy at sierra told me that there was a lot of unburnt powder and that will pile up in my supressor and could cause an issue. I like the n140 but im also having trouble getting a consistent CBTO since its compressed. I have a 9 inch (3 area 419 stacked up) drop tube and have used a vibrating toothbrush, but still get very inconsistent cbto. Do you have issues with this?
Click to expand...

Just make up some ammo and go shoot

If you're suppressors gets really gunked up or you have function issues maybe think about a powder change
 
#16
bross412 said:
are any of these compressed loads? I am having a hard time with the n140 getting a consistent CBTO because of the compressed powder. A buddy of mine has benchmark, so i may swing up by his place to try it out.
Click to expand...
The word "fill" and percentage is the amount of case fill above any over 100 percent are compressed loads.
Benchmark will be 100% fill so no compression, burnt is 96.86%

N 140 is a compressed load the burt percentage is pretty good depending on the pressure and amount of powder in your load 98 to 99% like 23 to 23.4 gr. It would be 108.1 percent fill. Or a compressed load...hence pushing back on bullet.

H322 is good burnt and fill not compressed for 14.5" barrel.
TAC only has 90% burnt in 14.5" barrel, so not recommend

AA 2495 22.6 gr 99.86,% burnt. 104.6 % fill.
Good velocity slightly compressed.
 
#17
45-90 said:
The word "fill" and percentage is the amount of case fill above any over 100 percent are compressed loads.
Benchmark will be 100% fill so no compression, burnt is 96.86%

N 140 is a compressed load the burt percentage is pretty good depending on the pressure and amount of powder in your load 98 to 99% like 23 to 23.4 gr. It would be 108.1 percent fill. Or a compressed load...hence pushing back on bullet.

H322 is good burnt and fill not compressed for 14.5" barrel.
TAC only has 90% burnt in 14.5" barrel, so not recommend

AA 2495 22.6 gr 99.86,% burnt. 104.6 % fill.
Good velocity slightly compressed.
Click to expand...
This is very helpful. I was thinking about trying out tac but now I won't.

I'm trying benchmark tomorrow morning
 
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#18
N135 is a better burn rate than N140 for your application. Vihta has improved the temperature stability of their 100 series powders compared to prior, although they aren't as temperature insensitive as the Hodgdon Extreme line. But they are forgiving to load, accurate, available, and not too expensive.

The other Hodgdon powders are great but availability is probably going to be spotty for any time in the near future. So if you are going that route then plan to stock up in bulk.

Another powder not mentioned here that is very temperature insensitive and clean burning in heavy 223 is 8208 XBR.
 
#25
I tried out benchmark today. A buddy had a lb laying around. All powder was thrown with a auto trickler v3. I started at 19gr and worked my way up to 22.5. Speeds were measured with a Garmin.

The best group / speed combo I could get was at 22gr with an avg speed of 2455 and a std of 11. The group was just about under an inch. Not horrible and will work for my application

22.5 had the speeds of about 2530 which is where I wanted to be, but the groups opened too much.

I think if I go with benchmark I'll go with 22gr.
 
#29
st1650 said:
You’ll want XBR and N133 out of a 14.5in. Varget is a bit too slow. XBR and 77smk/scenar is the easy butter for speed, temp sensitivity and burn rate.
Click to expand...
Can you give me your load data you have used and your speeds?? I won't directly copy it as I understand safety lol
 
#30
bross412 said:
Can you give me your load data you have used and your speeds?? I won't directly copy it as I understand safety lol
Click to expand...
With XBR, some (including myself) have gone all the way to 23.5-23.8 with the right chamber and the right brass and the right temperatures. This is well well well above max book. Even 22.5gr with the 77 is in 60K PSI territory on a hot day. Make sure you're using LC 556 brass and not the commercial LC 223.

N133 you can do 21-21.5 with 22gr being around 61K PSI but I would go no higher than 21-21.5 as the risk of hitting pressure and blowing primers is higher with N133 than with XBR.

XBR should also give you an approx 50FPS faster over N133 for the same pressure but N133 will give you a better/cleaner burn.
 

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#32
st1650 said:
With XBR, some (including myself) have gone all the way to 23.5-23.8 with the right chamber and the right brass and the right temperatures. This is well well well above max book. Even 22.5gr with the 77 is in 60K PSI territory on a hot day. Make sure you're using LC 556 brass and not the commercial LC 223.

N133 you can do 21-21.5 with 22gr being around 61K PSI but I would go no higher than 21-21.5 as the risk of hitting pressure and blowing primers is higher with N133 than with XBR.

XBR should also give you an approx 50FPS faster over N133 for the same pressure but N133 will give you a better/cleaner burn.
Click to expand...
I really appreciate it. I won't go anywhere near book max because I'll be shooting this rifle in the rain / mud / heat. I'd prefer to stay at a safe distance away from blowing up lol
 
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