What's the lowest SD you can get with 223?

[ashiha]

I have been trying my best to get my SD down in my 223 ammo, but can't seem to get it consistently below 20. It shows up as a fair amount of vertical dispersion on paper even at 100 yards.

I will reference this thread on Sniper's Hide that goes over the many things I have tried:
http://www.scout.com/military/snipe...-is-a-low-sd-obtainable-with-a-factory-barrel

Except now, it is still going on in my new WOA barrel on the AR. I also added neck turning and bullet sorting by length (base to ogive) to that list.

What have you guys been seeing in terms of benchrest quality 223 ammo?

 

[eric n]

Don't know if it's benchrest quality, but...
Sd of 8
Es in mid to high teens
223 is finicky. I had to turn necks, weigh to .04 g, and play with bushings to get it down.
Before doing that I could get mid 20s es but it actually shot better with a higher es.
The charge master will throw well enough to get it lower unless it's way off.
Haven't shot 69 smks in a while and threw my notes away so I cant comment on your load or speed. Do you know where you start seeing pressure signs?
I would start with cci 450s at minimum and work up, you should be able to get the chrony #s down.

How big are your groups at farther distances?
Low chrony #s are nice and we all shoot for them but all that matters is how close they land together, and 6s aren't bad for a factory barrel.

 

[ashiha]

Don't know if it's benchrest quality, but...
Sd of 8
Es in mid to high teens
223 is finicky. I had to turn necks, weigh to .04 g, and play with bushings to get it down.
Before doing that I could get mid 20s es but it actually shot better with a higher es.
The charge master will throw well enough to get it lower unless it's way off.
Haven't shot 69 smks in a while and threw my notes away so I cant comment on your load or speed. Do you know where you start seeing pressure signs?
I would start with cci 450s at minimum and work up, you should be able to get the chrony #s down.

How big are your groups at farther distances?
Low chrony #s are nice and we all shoot for them but all that matters is how close they land together, and 6s aren't bad for a factory barrel.

Thanks for the reply. I'm glad to hear that you also think that 223 is finicky. I haven't gotten to the pressures that cause signs as I am mostly using IMR 4064. Maybe I should try using an electric toothbrush to fit more powder in.

I say that I added neck turning to the mix, but I am not at all happy with the RCBS hand held neck turner that I bought. I should have listened and bought the 21st Century lathe. I also haven't tried working with the bushing dies. Would you say this is worth doing even if my neck turning isn't perfect?

At this point, I'm mostly just curious to see if I'm alone in struggling with the caliber or not. Like you said, 6s (and now 4s and 5s with the AR) are pretty good already. I just can't help but want more. I guess this is how benchrest shooting was born.

 

[1lnbrdg]

I always wondered if it wasn't varying amounts of recoil from the small .223 cartridge that might skew the ES. If it slides just a little more or less in the rests each time it fires, this would show on the chrono.

 

[eric n]

Try different powder and primer combinations. That, and being in a node,will have the biggest effect on es. Extensive case prep has meaningful, but smaller effects in my opinion.
Also,only change one thing at a time or you will be chasing your tail.

 

[jsthntn247]

I've been playing with loads in a 223 allot here lately. I started using a slower powder (hoping for better barrel and brass life) and the load was slightly compressed and yielded high ES in the 40fps range. It one holed at 100 but vertical showed at longer distance. I switched to a faster powder and ES is low 10-12fps range with SD around 4-5. I turn necks, measure tension, and load with a scale that measures to the kernel. Get your powder in a node then play with seating depth and neck tension and you should be able to easily get it under 20

 

[ashiha]

Sounds like it could be quite a bit of things.

I'll try running some Varget and IMR 4895 through again with full prep. I'll turn off the gas (adjustable gas block). I'll also try to let the rifle free recoil similar to how benchrest rifles are shot, but this may be a little difficult since the trigger pull isn't under 1lb.

However, I just want to be clear that I was getting the same results out of my Remington 700 in 223. So we aren't specifically talking about a gas gun issue.

Again, thanks for the replies. It means a lot to me when people try to help.

 

[Mozella]

Here's some data for you to chew on.
I chronographed 604 five-shot groups with my Howa 1500 .223 shooting mostly SMK 69gr with IMR 8208 XBR and got SDs from 2.22 to 123. Seven percent had SDs below 10. Some of these groups were shot with powder measured with the case activated powder dispenser and some were weighed. Some brass was casually prepared and included plenty of Lake City and Wolf.

With my Savage/Shilen .223 F/TR gun I chronographed 277 five-shot groups with SDs between 2.08 and 80. All charges were carefully weighed using a variety of powder, much of it Vihtavuori N-140, IMR 4198, and IMR 8208 XBR. Bullets were mostly moly coated Berger VLD 80gr or SMK moly coated 90gr. Fourteen percent of the groups had SDs better than 10. All the brass is Lapua carefully prepared

In comparison, my Savage/Shilen 6mm BR Norma shot 195 five-shot groups with SDs between 1.79 and 73, 30% of which had SDs better than 10. Powders were mostly CFE-223, IMR 4895, and IMR 8208 XBR and bullets were mostly Berger 105gr Hybrids, VLD Target, or VLD Hunting. All the brass is Lapua carefully prepared.

You can see that the 6BR gives much better SDs; I guess it's the nature of the beast. It's also easy to see that when I'm careful making .223 competition ammo, the SDs are much better, but still not nearly as good as the 6mm BR ammo. And making more casual ammo for a fun range gun, the SDs aren't as good.

However, and this is important, the SDs don't correlate very well with group size. Here is a plot of several thousand rounds showing both MOA and Group Height vs SD for my Howa 1500 .223 @ 100 yards. The trend line for MOA is nearly flat which means that even horrible SDs produce good MOA numbers and really small SDs can produce very bad MOA performance. Group height shows essentially the same thing.

SD vs Performance

Bottom Line: I strive for good SDs and low ESs. But this graph shows that I worry about it a LOT more than I should.

 

[skiutah02]

Challenge: if someone here can document, and have witnessed by someone with integrity, a 15 shot string, shot in less than 20 minutes using a 80+ grain projectile in a 223 Rem that has an ES in the single digits and 1MOA accuracy at 100 yds, I will send the first to do so $50.

Drew

I'm with others who have responded. I have fastidiously loaded, tested, etc, etc. this and can get SDs in the high single digits (most of the time) but if I can get ES in the mid teens (as outlined) I am elated. In the 20s hard, but doable. In the teens, an OCD test.

 

[eric n]

Challenge: if someone here can document, and have witnessed by someone with integrity, a 15 shot string, shot in less than 20 minutes using a 80+ grain projectile in a 223 Rem that has an ES in the single digits and 1MOA accuracy at 100 yds, I will send the first to do so $50.

Drew

I'm with others who have responded. I have fastidiously loaded, tested, etc, etc. this and can get SDs in the high single digits (most of the time) but if I can get ES in the mid teens (as outlined) I am elated. In the 20s hard, but doable. In the teens, an OCD test.

I've been playing around with the 90 smks till the vlds show up.
The last three 20 shot strings had sd of 8 on each, and 16,24,18 es respectively.
If I can find a babysitter tomorrow, I'll give it a whirl. The documented part will be hard, I don't know anyone here, but $50 bucks isn't going to cut it. We are going to play for blood...I'll need 2 90 vld bullets! (I need to throat a barrel I have waiting) haha
In all seriousness... if I can get out tomorrow I'll post the results.
I'm more worried about the group size, the magnetospeed makes my groups fly open horizontally pretty bad.

 

[skiutah02]

I've been playing around with the 90 smks till the vlds show up.
The last three 20 shot strings had sd of 8 on each, and 16,24,18 es respectively.
If I can find a babysitter tomorrow, I'll give it a whirl. The documented part will be hard, I don't know anyone here, but $50 bucks isn't going to cut it. We are going to play for blood...I'll need 2 90 vld bullets! (I need to throat a barrel I have waiting) haha
In all seriousness... if I can get out tomorrow I'll post the results.
I'm more worried about the group size, the magnetospeed makes my groups fly open horizontally pretty bad.

I'll include five 90vlds with the $50 if you can get'r done AND award you High Master Reloader.

 

[skiutah02]

Before you waste any 90s, he's talking about single digit ES for 15 shots, not SD. If it was merely single digit SD, I would be happily posting the required documentation and eagerly anticipating the impending transfer of $50 from Drew's pocket into mine in this very post. I have only once recorded a velocity string with the 90 VLDs that had an ES under 10 (it was 9 fps, IIRC), and that was for 10-shots, not 15.

Greg is one of the few that I think has a shot at collecting. As he pointed out, ES not SD. I've done only one 10 shot string that satisfied my own challenge and it cost me 10 Lapua brass when the primer pockets blew out.

 

[LHSmith]

The manner in which a rifle is held when fired is totally unrelated to muzzle velocity.POI will certainly change because the bullet is still in the barrel in the early stage of recoil. Dozens of other factors that can cause vertical besides the load. I know about Short range BR and little about AR's but I am pretty sure neck turning is not recommended for AR use- and striving for single digit SD's is counter-intutive in small capacity cases. If one measures the SD's on winning loads of SR BR cartridges, you will find them well into the teens or worse.

 

[eric n]

Whoops, missed the ES part....10 isn't going to happen!
At least my loads are better then my reading comprehension. lol.
Probably would have bit me in the butt and thrown up a 20 sd anyway. Saved me some excuses

 

[skiutah02]

Whoops, missed the ES part....10 isn't going to happen!
At least my loads are better then my reading comprehension. lol.
Probably would have bit me in the butt and thrown up a 20 sd anyway. Saved me some excuses

Unfortunately, the ES part is the critical part. While it would be bold of me to say it cannot be done. After over 3,000 rounds of 80s and 90s I'm confident in my inability to do it. Thus the challenge. I'll be shooting my best 223 load for a 1000yd match on Sat and we'll see how the vertical is with ES about 16 and SD around 6. Same load at Ben Avery held no more than 4.2 inches vertical for 12 shots at 1000 in Oct.

 

[ashiha]

The information posted in this thread is just mind blowing. I generally understood the concept that low SD doesn't necessarily correlate to the accuracy node, but have always felt that mine were still too high to be considered good enough. However, some of what you guys are saying implies that I am probably where I need to be and that it is just an issue with the caliber. This would mean that I should just leave the Magnetospeed at home and simply load for accuracy. I am using a variant of the loading concept posted by Eric Cortina on these forums somewhere.

I am just being floored by the effort you guys are putting forth here. Thank you all so much. This is something that has been bothering me for years now.

skiutah02, you mentioned Ben Avery's. Are you possibly located in Arizona? I live in Gilbert.

 

[skiutah02]

Disclaimer: this is my opinion, but with an abnormal amount of 223R experience with 80gr+ bullets in the past 1.5 years.

Precision and accuracy, on paper, for me, trumps all. The ideal to strive for is 0.25MOA 20+ shot accuracy, low ES, low SD, long barrel life and low cost. The 223 compared to most others inherently has the last two. With good load development, the first is achievable with higher than optimal ES/SD to 600ish yds. Somewhere beyond that, too high an ES/SD (whatever that is in your definition) will not allow high precision and accuracy observed at shorter distances. Have plenty of one-holer 100 yd targets with ES 100fps+. The further you get out the more important ES/SD is. 223R, in my experience, can raise eyebrows in the MidRange game. It has required me to substantiallay up my reloading skill (not a bad thing). But the pursuit of single digit ES has been unobtainable for me in 223R whereas 308, 6BRX and 6.5x47L have been.

I even went so far as to do this. 100 weight and volume sorted fireformed brass, neck-turned, annealed, etc were fired and velocity written on each case. ES for the 100 shots was around 35fps. I then combined all cases that shot in +-5 fps range and reshot them in 15-20 shot groups. Typical ES was about 20 for each group. Resorted again into under 5 fps ES range within each 20 and reshot. ES about 15. As you can see, I'm happy to contribute $50 to see if it's even possible in this cartridge.

Dont get me wrong, I LOVE shooting it and it has served we well of late.

Ashiha, Considering the people and facilities in Phoenix, I'd love to live there, but I'd go broke. I live in North Dakota and came down there for the FCLASS Nationals in Oct 2015.

Drew

 

[eric n]

ashihi
Yes. Always load for accuracy.
As far as the magnetospeed goes, some say it doesn't affect accuracy or poi, it does for me. Matter of fact, I just shot today with it on vs off. Opened up over a half minute like always. I use the chrony to get avg velocity and diagnose problems but can't get any meaningful load data with it on.

If your spreads are bugging you that much, run your #s through jbm and given the distance you shoot at make an honest assessment of your ability and see if 50fps matters. Then you know what you need to work on.
The guys are cool on here... I come from a fishing background where everything is hushhush super secret, very few share info like the guys do on here. Lots of smart cookies on here who go out of there way to help. My thanks as well. Besides, I'm glad to help. Gotta dispel the myth that a .223 drops out of the sky at 200 yds.


Drew,
Good luck. That last 100 yard is tough! I don't get to shoot that far very often but I know how hard it is.
Your posts, along with gstaylorg inspired me to shoot the 90's and start competing but work is getting in the way this year and my builds are collecting dust. I really need to get and do it as my wind calls need lots of improvement.

 

[GrocMax]

Magnetospeed seems to be sensitive to blade distance to bore/bullet, move it closer it appears to get a lot less measurement error and ES/SD tightens up with no other changes.

 

[ashiha]

Magnetospeed seems to be sensitive to blade distance to bore/bullet, move it closer it appears to get a lot less measurement error and ES/SD tightens up with no other changes.

Very interesting!

Another thing to try for sure!