Replacement for 8208 XBR IN AR-15 ?

[ma smith]

Where exactly are you finding N140 "way" cheaper than Staball? Everywhere I see it's in the $320 - $360 range which is right there with staball.

Powder : Smokeless : N140

In Stock Search and Alerts for Powder : Smokeless

www.shootingbot.com

 

[MK20]

you mean StaBALL? its objectively NOT a top tier powder. I laid out the reasons. You tell me. As a consumer, why would you buy StaBALL over VV N140? which is way cheaper and objectively superior in velocity and accuracy. I prefer W748, which I like a lot, and you can see on my site, I listed W748 as one of the best powders for 223. I shot one of the most ridiculous groups in my life with W748, at 200 yards. .76" at 200 yards? Using Berger 77 OTM. That is ridiculous accuracy for a 8 LB AR15, including scope just using a wooden rest, not even bipod.

Benchmark is my favorite powder for 223 "overall".

It seems that you do not value temperature insensitivity to the degree I do, which is fine. However, I would think that many here value that highly.

Can N140 beat 2820 fps with a 75gr in an 18 inch AR at .223 pressures? Cause that is what Match is giving me.

Match is a ball powder, where 140 isn't, so it should meter better.

I can get Match shipped to me for 324 per 8 lbs. I don't see 140 for noticeably cheaper than that. Per the above post there is a 10 dollar difference between the 2 powders for an 8 lb container.

And Match is temp stable as all get out, I have seen conflicting reports regarding 140 temp stability.

If you like 140, fine, but don't shit so hard on Match which is an excellent powder.

 

[semperfireloading]

Where exactly are you finding N140 "way" cheaper than Staball? Everywhere I see it's in the $320 - $360 range which is right there with staball.

Powder valley had N140 for like $279 and StaBALL for like $333. in stock. 8 lbs jugs. looks like they sold out within a week or so. I looked last week. I think the hardest powder to get on planet earth is probably 8208 XBR. everyone wants that powder.

 

[hellzna]

Powder valley had N140 for like $279 and StaBALL for like $333. in stock. 8 lbs jugs. looks like they sold out within a week or so. I looked last week. I think the hardest powder to get on planet earth is probably 8208 XBR. everyone wants that powder.

I haven’t even seen xbr in stock for a year + now.

 

[semperfireloading]

Ok fellas. First off, I did not mean to imply StaBALL match was a bad powder, the writeup I have on my site places it in the "good" category, and I said that if you value certain things in reloading, then its very good, and among the best you can get. But, accuracy is not going to be top tier with it in comparison to some other various powders. But its still good. I just think its pricey. N140 and N540 are temp stable, this is no conflict. However, they are NOT as temp stable as Varget. No way. but what is? That powder is super good.
MK20, yes Sir, you are correct, I do not value temp stable as much as you and many people on this board. I admit that. I would value it a lot more, if I was shooting 600-1000 yards often in a desert climate. But I live in a "subtropical" climate, and I really only shoot big volume under 300 yards. I am like the majority, but its like knives, everything has its application.

I am happy to make this test for you fellas. I hope it helps you in your buying decisions. Sometimes powder is so hard to find, and you wait a long time, and you get tired of waiting and you want to get something now. So this can help, along with my site, perhaps.

here was the loads: all using WOA Shilen 20" barrel 1:7.5 twist. Labradar. 75 degrees. NEW BRASS, the brass was sorted, and all the brass was very near ~94 grains weight. Primers were all the same kind, small rifle. 2.260 OAL for all using 77 grain Sierra MATCHKINGS.
Varget 23.7 (5 shots) & 24.9 (3 shots) (top of bin of brass, row #1 at top)
Shooters World Precision Rifle 23.7 (5 shots) & 24.9 (3 shots) (row #2 from top)
StaBALL Match 24.0 (5 shots) & 25.2 (3 shots) (row #3 from top on brass pic)
8208 XBR 23.2 (5 shots) & 23.6 (3 shots)
N140 24.7 (5 shots) & 24.1 (3 shots)
N540 25.3 (5 shots) & 24.5 (3 shots)
Alliant RL15 24.1 (5 shots) & 24.9 (3 shots) (row #7, etc)
Benchmark 22.8 (5 shots) & 23.3 (3 shots) (row #8 with primers removed, so I could measure them)
The first load listed with 5 shots, is using the MAXIMUM BOOK Charge from the "Powder" manufacturer. Hodgdon, SW, VV, Alliant, for 77 SMK @ 2.260. ALL THESE GROUPS SHOT AT 50 YARDS. I had to shoot at something...but accuracy not big deal here, its velocity we testing.

Now, this story tells us many things. Many of which some of you already mentioned. The most important thing to know is that the chamber of the gun is huge factor. I have another WOA 20" barrel that is 75-100FPS higher than this Shilen, same loads. I used this Shilen because it gives me nearly exact same FPS as the CLE Barrels I have, and the Bartlien, the Kriegers, and some others. in 20". So its consistently normal.

Here are some interesting takeaways:

1. I have no idea what "true" book max of SW PR is, I am guessing its like 23.9, or near it. 23.7 too low. The book max on SW site is totally wrong and WAY conservative, so I did not use it, and just mirrored the Varget, which SW PR is designed to "be like". So ignore that max.
2. StaBALL match is the lowest "book max" velocity of the group, however, it makes up for it by being stable at well over 1 grain over max, as its pressure curve is linear, not spikey. I would say its similar to AA2520 or SW Match Rifle, for sure, except its more temp stable. So if you value temp stable, this is probably best ball powder option you can buy. If you can't find this, buy AA2520.
3. VV load data is wonky, like so many. No way in heavens is 55k pSI 24.7 N140 using the combination I used. NO WAY. If I was to guess, I would say 24.7 is around 60k psi. This is exactly why I did NOT load the 3 shots with MORE powder, like I did with so many others, because I knew 24.7 is not right, and way over max SAAMI. I believe max SAAMI with N140 to be 24.1, and Berger apparently knows this too, because I just bought many boxes of 77 grain OTM commercial bullets, and they were 24.1 N140, and got the same results.
4. VV N140 24.1 vs Varget 23.7 similar pressure, and the N140 is 90 FPS faster.
5. VV N540. I knew 25.3 is a joke and WAYYY too high, again, I think this is probably like 62k PSI or something higher than even NATO, but not sure, because the brass was re-usable, and it did 2,885 FPS which is outrageous. ZERO popped primers, shot fine. Brass has small burs, and stamped, but not super bad. I use N540 all the time, and I use 24.5 grains, which I believe to be SAAMI Max, of 55k PSI. It was 2812 FPS with an SD of 11. This is actually one of the better loads for an AR15. N540 using 0.8 grains UNDER what the manufacturer says is max, which is what I think is 55k PSI, is OVER 150 FPS more than Varget, and 200 FPS over StaBALL Match, similar pressure.
6. RL15 is a top tier powder for a long time, guys use it for 600 hi-power commonly. Its NOT temp stable. But you can see why its so popular. 2744 FPS using SAAMI max. And brass looks like that is correct.
7. Varget is accurate, its almost hard to find a bad load with it. Its so good. However, at SAAMI max, it is not high energy, and needs to go beyond to achieve MK262 velocity, as I demonstrated here. Case starts to get pretty full and its quite compressed. But still shot good.
8. 8208 XBR. You can see why this powder is so sought after. You only need a SMALL amount over maximum to go into orbit with velocity. Notice how so many powders need "1 entire grain" over book max, to achieve MK262 (2750 FPS). But powders like XBR only need a fraction of that, and they get there easily. And case fill is superior with no big compression. This is why people like it, and its temp stable.
9. Benchmark at 23.3 grains hit the MK262 realm. And this was 3 shots. but still...SD was 1. that made me laugh.

I have tested all these powders, many many times. And for 77 SMK here is my picks, in order of what I would use, if I was going to do a 600 yard tournament

1. N140
2. N540
3. 8208 XBR
4. Varget
5. SW PR
6. StaBALL Match
7. RL15
8. Benchmark (not as accurate in higher FPS as above list, and 77 grain bullets not its strength, although 22 grains ~2600 FPS is a great load)

The guys I talk to who compete all the time, and take this dead serious, basically use N140, Varget, XBR, SW PR, H4895, 2520, 2460, RL15, N540, N135

Hey MK20 LOOK!!! Look at VV's Marketing right on the jugs. They are trying to hypnotize you!! Look what it says on both "temperature stable, Decoppering agent, clean burning". I think they left out "takes out the trash and does the laundry" cuz damn these powders are REAL good.
Have a good evening fellas.

 

[ZA206]

Solid report and great shooting!

 

[MK20]

Ok fellas. First off, I did not mean to imply StaBALL match was a bad powder, the writeup I have on my site places it in the "good" category, and I said that if you value certain things in reloading, then its very good, and among the best you can get. But, accuracy is not going to be top tier with it in comparison to some other various powders. But its still good. I just think its pricey. N140 and N540 are temp stable, this is no conflict. However, they are NOT as temp stable as Varget. No way. but what is? That powder is super good.
MK20, yes Sir, you are correct, I do not value temp stable as much as you and many people on this board. I admit that. I would value it a lot more, if I was shooting 600-1000 yards often in a desert climate. But I live in a "subtropical" climate, and I really only shoot big volume under 300 yards. I am like the majority, but its like knives, everything has its application.

I am happy to make this test for you fellas. I hope it helps you in your buying decisions. Sometimes powder is so hard to find, and you wait a long time, and you get tired of waiting and you want to get something now. So this can help, along with my site, perhaps.

here was the loads: all using WOA Shilen 20" barrel 1:7.5 twist. Labradar. 75 degrees. NEW BRASS, the brass was sorted, and all the brass was very near ~94 grains weight. Primers were all the same kind, small rifle. 2.260 OAL for all using 77 grain Sierra MATCHKINGS.
Varget 23.7 (5 shots) & 24.9 (3 shots) (top of bin of brass, row #1 at top)
Shooters World Precision Rifle 23.7 (5 shots) & 24.9 (3 shots) (row #2 from top)
StaBALL Match 24.0 (5 shots) & 25.2 (3 shots) (row #3 from top on brass pic)
8208 XBR 23.2 (5 shots) & 23.6 (3 shots)
N140 24.7 (5 shots) & 24.1 (3 shots)
N540 25.3 (5 shots) & 24.5 (3 shots)
Alliant RL15 24.1 (5 shots) & 24.9 (3 shots) (row #7, etc)
Benchmark 22.8 (5 shots) & 23.3 (3 shots) (row #8 with primers removed, so I could measure them)
The first load listed with 5 shots, is using the MAXIMUM BOOK Charge from the "Powder" manufacturer. Hodgdon, SW, VV, Alliant, for 77 SMK @ 2.260. ALL THESE GROUPS SHOT AT 50 YARDS. I had to shoot at something...but accuracy not big deal here, its velocity we testing.

Now, this story tells us many things. Many of which some of you already mentioned. The most important thing to know is that the chamber of the gun is huge factor. I have another WOA 20" barrel that is 75-100FPS higher than this Shilen, same loads. I used this Shilen because it gives me nearly exact same FPS as the CLE Barrels I have, and the Bartlien, the Kriegers, and some others. in 20". So its consistently normal.

Here are some interesting takeaways:

1. I have no idea what "true" book max of SW PR is, I am guessing its like 23.9, or near it. 23.7 too low. The book max on SW site is totally wrong and WAY conservative, so I did not use it, and just mirrored the Varget, which SW PR is designed to "be like". So ignore that max.
2. StaBALL match is the lowest "book max" velocity of the group, however, it makes up for it by being stable at well over 1 grain over max, as its pressure curve is linear, not spikey. I would say its similar to AA2520 or SW Match Rifle, for sure, except its more temp stable. So if you value temp stable, this is probably best ball powder option you can buy. If you can't find this, buy AA2520.
3. VV load data is wonky, like so many. No way in heavens is 55k pSI 24.7 N140 using the combination I used. NO WAY. If I was to guess, I would say 24.7 is around 60k psi. This is exactly why I did NOT load the 3 shots with MORE powder, like I did with so many others, because I knew 24.7 is not right, and way over max SAAMI. I believe max SAAMI with N140 to be 24.1, and Berger apparently knows this too, because I just bought many boxes of 77 grain OTM commercial bullets, and they were 24.1 N140, and got the same results.
4. VV N140 24.1 vs Varget 23.7 similar pressure, and the N140 is 90 FPS faster.
5. VV N540. I knew 25.3 is a joke and WAYYY too high, again, I think this is probably like 62k PSI or something higher than even NATO, but not sure, because the brass was re-usable, and it did 2,885 FPS which is outrageous. ZERO popped primers, shot fine. Brass has small burs, and stamped, but not super bad. I use N540 all the time, and I use 24.5 grains, which I believe to be SAAMI Max, of 55k PSI. It was 2812 FPS with an SD of 11. This is actually one of the better loads for an AR15. N540 using 0.8 grains UNDER what the manufacturer says is max, which is what I think is 55k PSI, is OVER 150 FPS more than Varget, and 200 FPS over StaBALL Match, similar pressure.
6. RL15 is a top tier powder for a long time, guys use it for 600 hi-power commonly. Its NOT temp stable. But you can see why its so popular. 2744 FPS using SAAMI max. And brass looks like that is correct.
7. Varget is accurate, its almost hard to find a bad load with it. Its so good. However, at SAAMI max, it is not high energy, and needs to go beyond to achieve MK262 velocity, as I demonstrated here. Case starts to get pretty full and its quite compressed. But still shot good.
8. 8208 XBR. You can see why this powder is so sought after. You only need a SMALL amount over maximum to go into orbit with velocity. Notice how so many powders need "1 entire grain" over book max, to achieve MK262 (2750 FPS). But powders like XBR only need a fraction of that, and they get there easily. And case fill is superior with no big compression. This is why people like it, and its temp stable.
9. Benchmark at 23.3 grains hit the MK262 realm. And this was 3 shots. but still...SD was 1. that made me laugh.

I have tested all these powders, many many times. And for 77 SMK here is my picks, in order of what I would use, if I was going to do a 600 yard tournament

1. N140
2. N540
3. 8208 XBR
4. Varget
5. SW PR
6. StaBALL Match
7. RL15
8. Benchmark (not as accurate in higher FPS as above list, and 77 grain bullets not its strength, although 22 grains ~2600 FPS is a great load)

The guys I talk to who compete all the time, and take this dead serious, basically use N140, Varget, XBR, SW PR, H4895, 2520, 2460, RL15, N540, N135

Hey MK20 LOOK!!! Look at VV's Marketing right on the jugs. They are trying to hypnotize you!! Look what it says on both "temperature stable, Decoppering agent, clean burning". I think they left out "takes out the trash and does the laundry" cuz damn these powders are REAL good.
Have a good evening fellas.

This now makes sense to me why you have the perspective you do.

The temperatures where I live range from -10 to 100 deg F in a year regularly.

I also take my 223 guns out to 1K regularly and shots on coyotes and wolves can EASILY be in the 600M realm.

So you can see why for me temp stability is at a premium. I also load all my 223 on a Dillon, so metering is key.

I understand why you would prefer the absolute best accuracy you can get in your situation. I prefer the most ballistic arc consistency instead.

 

[ma smith]

I would like to note--despite testing almost every top-tier powder for .223--
how few loads in the test have true single digit SDs

 

[bobke]

Just curious, as AR Comp was not included in your test, but you have noted how well it’s done with 55 Bergers in your previous testing on site. It’s cooler burning, pretty temp stable, runs in a similar burn rate to many of these powders-though perhaps on the faster side, and is finally showing up in stock of late. I use it for 223 up through 77gr Sierras, 6.5 Grendel and 308 with lighter bullets very successfully with low SD, good velocity and accuracy.
Good testing and validation of discussion, but would like to have seen AR Comp on a level playing field with this other competition. Good work.

 

[MJF]

I have four pounds of N140 headed my way. Thank you for all of the information!

 

[semperfireloading]

I would like to note--despite testing almost every top-tier powder for .223--
how few loads in the test have true single digit SDs

Thank you. This is because, as you know, when you only test what "book max" is, and not a range of loads, you are not nec. hitting the nodes that make super low SD. So you may load .1 grains different, and get half the SD, or .2 more or less, etc. Which such sparce data here with each powder in load data, it would be pure luck if most were sub 10. In my experience, testing AR15's and every powder I can buy on the face of the planet, I would say an "average" SD I see, is around 12-15 depending on how many shots you take. The lowest SD powders I have ever shot, bar none, are Alliant Powders. RL15.5 and RL16, and Ar Comp. Also with pistol powders in 223 going for subsonic, N330 gave me SD of "1" using cotton in the case to pack it down.

bobke: I respect your request, you can see I listed AR Comp as top tier 223 powder, next to Benchmark. AR Comp is actually NOT commonly used for 77 grain bullets, as its faster burning than Benchmark even. But it can do 2750 FPS as you know. There are many powders I left out that can do 2750, but are not super widely used, N135 and AA2520 would be top 2 missing that are more common.

With AR Comp and 77 SMK, the high end will be 22.6-22.8 or so, and one of those will be good accuracy and high velocity. its a good powder.

 

[Mike_in_FL]

I haven’t even seen xbr in stock for a year + now.

Have you tried using the reloading group in the Discord server? That's how I got some although I agree that it seems like there's one shipment per year and once it's gone, wait another.

 

[ma smith]

In my experience, testing AR15's and every powder I can buy on the face of the planet, I would say an "average" SD I see, is around 12-15 depending on how many shots you take.

This is my experience as well, I think your numbers are accurate. Mk262 class speed with 223 Rem is very difficult to load at low SD. The main comment to make from here is SD is more critical than group size for guys trying to stretch out 223 Rem beyond 5/600 yards.

 

[NHPiper]

StaBall Match Testing - 77gr Reloads, Chasing mk262

In the quest for a Mk262 duplicate load, I am playing around with the new Wincheste, and since 8208 XBR is impossible to source StaBall Match powder. Early reports indicate that it is very temp stable (less than 0.82fps per degree of F), which is unusual for this type of powder structure. The...

www.snipershide.com

 

[hellzna]

Have you tried using the reloading group in the Discord server? That's how I got some although I agree that it seems like there's one shipment per year and once it's gone, wait another.

Thank you.

I have, but cannot remember the last time I ever saw it pop up.

 

[supercorndogs]

I would like to note--despite testing almost every top-tier powder for .223--
how few loads in the test have true single digit SDs

I would like to note, how many case head smears and flat primers I see.

 

[MJF]

How well does N140 meter through a Dillon powder measure? I load my AR ammo on a Dillon 550B. Proper metering is crucial to accurate ammo when using a Dillon. StaBall Match & N140 look like good replacements for 8208. I do need temp stable as the temp in my AO goes from 10* to 90*. Graffs made an error and I have both powders arriving today, so I'll need to choose one since I want it to be one and done.

 

[MK20]

How well does N140 meter through a Dillon powder measure? I load my AR ammo on a Dillon 550B. Proper metering is crucial to accurate ammo when using a Dillon. StaBall Match & N140 look like good replacements for 8208. I do need temp stable as the temp in my AO goes from 10* to 90*. Graffs made an error and I have both powders arriving today, so I'll need to choose one since I want it to be one and done.

This is why I like Match. It is a ball powder and measures perfectly. It will hold within a tenth on the Dillon.

 

[ma smith]

How well does N140 meter through a Dillon powder measure? I load my AR ammo on a Dillon 550B. Proper metering is crucial to accurate ammo when using a Dillon. StaBall Match & N140 look like good replacements for 8208. I do need temp stable as the temp in my AO goes from 10* to 90*. Graffs made an error and I have both powders arriving today, so I'll need to choose one since I want it to be one and done.

Nobody can really answer this for you.

 

[264pr]

Ok fellas. First off, I did not mean to imply StaBALL match was a bad powder, the writeup I have on my site places it in the "good" category, and I said that if you value certain things in reloading, then its very good, and among the best you can get. But, accuracy is not going to be top tier with it in comparison to some other various powders. But its still good. I just think its pricey. N140 and N540 are temp stable, this is no conflict. However, they are NOT as temp stable as Varget. No way. but what is? That powder is super good.
MK20, yes Sir, you are correct, I do not value temp stable as much as you and many people on this board. I admit that. I would value it a lot more, if I was shooting 600-1000 yards often in a desert climate. But I live in a "subtropical" climate, and I really only shoot big volume under 300 yards. I am like the majority, but its like knives, everything has its application.

I am happy to make this test for you fellas. I hope it helps you in your buying decisions. Sometimes powder is so hard to find, and you wait a long time, and you get tired of waiting and you want to get something now. So this can help, along with my site, perhaps.

here was the loads: all using WOA Shilen 20" barrel 1:7.5 twist. Labradar. 75 degrees. NEW BRASS, the brass was sorted, and all the brass was very near ~94 grains weight. Primers were all the same kind, small rifle. 2.260 OAL for all using 77 grain Sierra MATCHKINGS.
Varget 23.7 (5 shots) & 24.9 (3 shots) (top of bin of brass, row #1 at top)
Shooters World Precision Rifle 23.7 (5 shots) & 24.9 (3 shots) (row #2 from top)
StaBALL Match 24.0 (5 shots) & 25.2 (3 shots) (row #3 from top on brass pic)
8208 XBR 23.2 (5 shots) & 23.6 (3 shots)
N140 24.7 (5 shots) & 24.1 (3 shots)
N540 25.3 (5 shots) & 24.5 (3 shots)
Alliant RL15 24.1 (5 shots) & 24.9 (3 shots) (row #7, etc)
Benchmark 22.8 (5 shots) & 23.3 (3 shots) (row #8 with primers removed, so I could measure them)
The first load listed with 5 shots, is using the MAXIMUM BOOK Charge from the "Powder" manufacturer. Hodgdon, SW, VV, Alliant, for 77 SMK @ 2.260. ALL THESE GROUPS SHOT AT 50 YARDS. I had to shoot at something...but accuracy not big deal here, its velocity we testing.

Now, this story tells us many things. Many of which some of you already mentioned. The most important thing to know is that the chamber of the gun is huge factor. I have another WOA 20" barrel that is 75-100FPS higher than this Shilen, same loads. I used this Shilen because it gives me nearly exact same FPS as the CLE Barrels I have, and the Bartlien, the Kriegers, and some others. in 20". So its consistently normal.

Here are some interesting takeaways:

1. I have no idea what "true" book max of SW PR is, I am guessing its like 23.9, or near it. 23.7 too low. The book max on SW site is totally wrong and WAY conservative, so I did not use it, and just mirrored the Varget, which SW PR is designed to "be like". So ignore that max.
2. StaBALL match is the lowest "book max" velocity of the group, however, it makes up for it by being stable at well over 1 grain over max, as its pressure curve is linear, not spikey. I would say its similar to AA2520 or SW Match Rifle, for sure, except its more temp stable. So if you value temp stable, this is probably best ball powder option you can buy. If you can't find this, buy AA2520.
3. VV load data is wonky, like so many. No way in heavens is 55k pSI 24.7 N140 using the combination I used. NO WAY. If I was to guess, I would say 24.7 is around 60k psi. This is exactly why I did NOT load the 3 shots with MORE powder, like I did with so many others, because I knew 24.7 is not right, and way over max SAAMI. I believe max SAAMI with N140 to be 24.1, and Berger apparently knows this too, because I just bought many boxes of 77 grain OTM commercial bullets, and they were 24.1 N140, and got the same results.
4. VV N140 24.1 vs Varget 23.7 similar pressure, and the N140 is 90 FPS faster.
5. VV N540. I knew 25.3 is a joke and WAYYY too high, again, I think this is probably like 62k PSI or something higher than even NATO, but not sure, because the brass was re-usable, and it did 2,885 FPS which is outrageous. ZERO popped primers, shot fine. Brass has small burs, and stamped, but not super bad. I use N540 all the time, and I use 24.5 grains, which I believe to be SAAMI Max, of 55k PSI. It was 2812 FPS with an SD of 11. This is actually one of the better loads for an AR15. N540 using 0.8 grains UNDER what the manufacturer says is max, which is what I think is 55k PSI, is OVER 150 FPS more than Varget, and 200 FPS over StaBALL Match, similar pressure.
6. RL15 is a top tier powder for a long time, guys use it for 600 hi-power commonly. Its NOT temp stable. But you can see why its so popular. 2744 FPS using SAAMI max. And brass looks like that is correct.
7. Varget is accurate, its almost hard to find a bad load with it. Its so good. However, at SAAMI max, it is not high energy, and needs to go beyond to achieve MK262 velocity, as I demonstrated here. Case starts to get pretty full and its quite compressed. But still shot good.
8. 8208 XBR. You can see why this powder is so sought after. You only need a SMALL amount over maximum to go into orbit with velocity. Notice how so many powders need "1 entire grain" over book max, to achieve MK262 (2750 FPS). But powders like XBR only need a fraction of that, and they get there easily. And case fill is superior with no big compression. This is why people like it, and its temp stable.
9. Benchmark at 23.3 grains hit the MK262 realm. And this was 3 shots. but still...SD was 1. that made me laugh.

I have tested all these powders, many many times. And for 77 SMK here is my picks, in order of what I would use, if I was going to do a 600 yard tournament

1. N140
2. N540
3. 8208 XBR
4. Varget
5. SW PR
6. StaBALL Match
7. RL15
8. Benchmark (not as accurate in higher FPS as above list, and 77 grain bullets not its strength, although 22 grains ~2600 FPS is a great load)

The guys I talk to who compete all the time, and take this dead serious, basically use N140, Varget, XBR, SW PR, H4895, 2520, 2460, RL15, N540, N135

Hey MK20 LOOK!!! Look at VV's Marketing right on the jugs. They are trying to hypnotize you!! Look what it says on both "temperature stable, Decoppering agent, clean burning". I think they left out "takes out the trash and does the laundry" cuz damn these powders are REAL good.
Have a good evening fellas.

I've tried a number of different powders including 2520 which wasnt terribad but N540 yielded best results for me.

VV's load data for N540 is pretty high in my experience.

I worked up to 25.1 gr under 77gr SMK and tapped out due to primers flattening beyond my comfort range.....still a hint of rounding on edge.....but almost square.

25gr appears to be a sweet spot for accuracy for my gear and is producing velocities just over 2800 in an 18" barrel

Primers are starting to flatten out but still have clearly visible rounding on the edges and no deformation at firing pin strike

Brass looks good, no ejector swipes or signs of pressure that would concern me.

Hoping to see this weekend if things change as temp increases.....so far been shooting in temps 55 and below.

If things work out this is an accurate load with XBR like velocity and energy on target and good SD's

 

[ma smith]

One other issue to keep in mind what each powder does to your barrel. While any Mk262 load is going to cut back your barrel life a bit, N540 yields like half the typical .223 barrel life. This guy has a barrel-life calculator, its worth playing around with if this metric is of interst to you.

Barrel Life Calculator

pierrevanderwalt.com

25gr n540 is ±2800 rounds
23.5gr XBR is ±3500
24gr N140 is ±4400 rounds
22.5 of AR-comp is ±4800

 

[357Max]

One other issue to keep in mind what each powder does to your barrel. Keep in mind, any Mk262 load is going to cut back your barrel life a bit, but N540 is like half the typical .223 barrel life. This guy has a barrel-life calculator, its worth playing around with if this metric is of interst to you.

Barrel Life Calculator

pierrevanderwalt.com

25gr n540 is ±2800 rounds
23.5gr XBR is ±3500
24gr N140 is ±4400 rounds
22.5 of AR-comp is ±4800

Interesting hadn’t seen that before.

25.3gr AA2520 is 4017
That is the MK262 load I settled on.

 

[Yondering]

What is interesting, is AA2520, for a ball powder, is not that temp sensitive at all.

2520 can be VERY temp sensitive. Like all powders, temp sensitivity varies with the load and a bunch of other factors, so don't believe just a single number on some random chart. The temp sensitivity isn't even necessarily linear, which can be seen if you actually test in different temperatures with the rifle and ammo stabilized at temp (not the stupid & flawed "ammo in a cooler" kind of test).

Working up a good load with 2520 in the spring or fall can easily have you blowing primer pockets in the heat of the summer. That won't happen with 8208 or Benchmark (which IS actually a pretty decent 75/77gr 5.56 accuracy powder).

 

[ClamHammerXpress]

Read an article in Shooting Times the other day that addressed this very topic and as it turns out, AA LT–32 is the direct descendant of 8208 XBR…by way of T-32 if anyones eld enough to be familiar with that gem of yesteryear