Reducing SD by trying different powders and primers in 223AI

[L.Sherm]

50fps at 800m with 80 ELDM is 0.30 Mils or 24cm

Have you shot this to confirm it or using a ballistics app? If its the latter well you better shoot it you might be surprised or maybe not. Believe the target!!

 

[Dwubyd]

Ballistics app.

 

[Dwubyd]

Another day at the range today.

I did an OCW test for Benchmark 2. 25.4-25.8 grains looks promising. Good SDs and one group was 0.1". 25.8gn gives around 2950 fps.

Generally groups were better with noticeably fewer fliers. This may be due to trimming and squaring off the case necks, neck turning and sizing with a mandrel neck sizer rather than the expander button in the FL die.

PRS match on Saturday, then on to next steps for the testing.

 

[Turpentine]

That is a lot of difference between Lapua brass and other brass. Did the neck turning improve the ES of the Lapua brass?

Also, from the experiences that people are sharing, aiming for single digit SD in a 223 is over ambitious and a bit unrealistic. I will be happy if I can get ES down to 30, then I can start focussing on group sizes.

When using 30/06 Lapua Brass and sizing down to 6.5 my necks thicken to the point that neck turning is imperative. Otherwise there is not enough room for adequate expansion when firing. I neck size using a bushing/bump die and then turn the necks. I cannot tell you whether the neck sizing improved es in this case because it is a step that I have to do regardless. I wish I could give you a more definite answer. In one of my 308s using LC brass I do see improved ES when I outside skim the necks to make them more uniform. I size those cases using an RCBS X DIE which uses a mandrel of sorts. They do still make the X die in a 223 I believe. I have one and like it. It keeps brass from lengthening during sizing.

 

[RabbitSlayer]

223 and 204 several guns powders and primers thousands of rounds experimenting. When I chrono 25 or more, an ES of 70 is about all I can get in factory guns using starline and Fiocchi brass. The starline is better. I think a lot of low es on the internet is small sample size.

I was measuring necks to pick the case to sacrifice for Aztec mode the other day. The starline brass has a lot of variation from one side to the other. I think neck turning would help. Im not going down that rabbit hole. Hoping the second firing makes an improvement.

I think lapua brass would help but its been hard to find in .223.

These are all factory chambers.

In comparison, 6 creed with hornady brass I got 30 fps for 25 shots with no effort. When I measure those necks they are way more consistent from side to side and 10 cases all measured the same. This is a saami reamer, but chambered by the local smith.

I am waiting on a 223ai barrel, but im not expecting es miracles...

 

[DHD]

When you say accurate, what exactly do you mean? Consistently shoots 3 shots into 1" at 100y? That would be good for a factory hunting rifle. Or do you mean 5 shots into 0.3" at 100y or 10 into 3" at 500m?

For the hunting rifle at 100y, ES does not really matter, as you said. However if you are trying to hit a 0.5 mil gong at 800m, it does matter.

50fps at 800m with 80 ELDM is 0.30 Mils or 24cm.

Not sure if your post was directed towards my rambling but I will answer as if it was. I shoot 5 shot groups unless I am looking for something and then I will shoot 10 shot groups regardless if it is an AR or boltgun.

The 223 AR's of mine, with one exception, will shoot into 1" (new Criterion that has 100 rounds through it), 3/4" (Proof), and again 3/4" (Shilen Ratchet). The exception is a Craddock Bartlein but it is a 10" and not an easy thing to target shoot for accuracy.

The above is at 100 but all have been shot to 300, and the Proof and Shilen have been grouped at 600. At 600 I have seen more vertical in the groups that I don't attribute to me or environmental. I suspect highly that the ES is the 800lb gorilla there.

I enjoy shooting them but find the 223 to not be an easy button for low sd's or es. I shot BPCR's for years (occasionally still do) and if the sd's were out of the single digits for a 20 shot string, something was wrong. Not apples to apples but interesting to me.

Pardon the rambling again...

 

[Dwubyd]

DHD, it occurred to me the other day that there is a certain amount of inherent randomness, that will show up at any range with a rifle (you could call it "variation in the DIRECTION of the velocity vector of the projectile as it leaves the barrel). There is also variation in speed (variation in the MAGNITUDE of the velocity vector of the projectile as it leaves the barrel), however that will show up more at longer ranges as vertical spread. These two sources of error add together to give the result we see on the target.

BTW, I got a bore scope the other day. Illuminating and horrifying. My 223AI barrel has many large patches of corrosion along the last 2/3 of the barrel. I have noticed on the forums that people warn not to get too caught up with what you see using a bore scope. Many rifles with bad looking bores shoot fine, and how the rifle shoots is all that matters at the end of the day.

 

[DHD]

The first time I used a borescope 10 + years ago (Hawkeye with the 90° eyepiece $$$) it showed me that my cleaning was spot on....for the last 18" of that barrel. When I was able to understand what I was seeing, I realized what hard carbon looked like and how hard it is to remove. I haven't let a barrel get that way since. As soon as the Teslong scopes came out, I've used one of them instead. It is the only way to know that you can spend more money on a new barrel that you might not need yet.

I have a terminal type of ADHD that makes me spend money on different types of rifles and I have been on an AR15 kick for a few years. I suppose it is mainly because they are Las Vegas prostitutes (no matter how much money you spend on them, they'll always break your heart). A tried and true custom boltgun with a great barrel and stock will never do you wrong, but where is the fun in that? Did you know if you try hard enough, you can spend almost as much money on an AR as a full custom boltgun?

None of this though allows me to get the sd's in a 223 that I can get easily in a BR, Grendel, 6 or 6.5×47, or even 308 case. Well, off to more experimenting.

 

[searcher]

Ballistics app.

The first time I used a borescope 10 + years ago (Hawkeye with the 90° eyepiece $$$) it showed me that my cleaning was spot on....for the last 18" of that barrel. When I was able to understand what I was seeing, I realized what hard carbon looked like and how hard it is to remove. I haven't let a barrel get that way since. As soon as the Teslong scopes came out, I've used one of them instead. It is the only way to know that you can spend more money on a new barrel that you might not need yet.

I have a terminal type of ADHD that makes me spend money on different types of rifles and I have been on an AR15 kick for a few years. I suppose it is mainly because they are Las Vegas prostitutes (no matter how much money you spend on them, they'll always break your heart). A tried and true custom boltgun with a great barrel and stock will never do you wrong, but where is the fun in that? Did you know if you try hard enough, you can spend almost as much money on an AR as a full custom boltgun?

None of this though allows me to get the sd's in a 223 that I can get easily in a BR, Grendel, 6 or 6.5×47, or even 308 case. Well, off to more experimenting.

I have strived for many years to squeeze accuracy out of a .223. Anyway, I found that the smaller a cartridge case mouth is, the higher the benefits realized in accuracy gains (and much lower SD's) by turning the necks. Before that, I found that moly coating my bullets greatly reduced SD's. Doing both can get the SD's down to what you want. I routinely get low single-digits now. Not 2's to 4's as a rule, but no problem getting 5's to 8's. That is pretty good compared to the 12-15+ I normally get without doing these things. I think brass turned on an IDOD would help further my quest - but that is some big dough for maybe a few numbers lower (at best). Now, thanks to the ridiculously portable chronograph, I chrono everything I shoot and still continue to find ways to tweak those little cartridges. It sometimes seems I'm the only one still using moly, as I never hear of anyone talk about the benefits anymore. But in a .223, I can't imagine as easily getting the SD's I get without it.

 

[natdscott]

The first time I used a borescope 10 + years ago (Hawkeye with the 90° eyepiece $$$) it showed me that my cleaning was spot on....for the last 18" of that barrel. When I was able to understand what I was seeing, I realized what hard carbon looked like and how hard it is to remove. I haven't let a barrel get that way since. As soon as the Teslong scopes came out, I've used one of them instead. It is the only way to know that you can spend more money on a new barrel that you might not need yet.

I have a terminal type of ADHD that makes me spend money on different types of rifles and I have been on an AR15 kick for a few years. I suppose it is mainly because they are Las Vegas prostitutes (no matter how much money you spend on them, they'll always break your heart). A tried and true custom boltgun with a great barrel and stock will never do you wrong, but where is the fun in that? Did you know if you try hard enough, you can spend almost as much money on an AR as a full custom boltgun?

None of this though allows me to get the sd's in a 223 that I can get easily in a BR, Grendel, 6 or 6.5×47, or even 308 case. Well, off to more experimenting.

I mean... premium AR's are pretty easy to get to 1/2 Minute.

There are a metric ****load of bolt rifles that won't do that.

But yes, a $2,000 bolt gun will more easily-cut the middles out of targets than will an equally expensive AR, all else equal (and proper).

Best thing you could do for your AR velocity woes is to put the -15 AWAY when you want to radar something.

 

[searcher]

I mean... premium AR's are pretty easy to get to 1/2 Minute.

There are a metric ****load of bolt rifles that won't do that.

But yes, a $2,000 bolt gun will more easily-cut the middles out of targets than will an equally expensive AR, all else equal (and proper).

Best thing you could do for your AR velocity woes is to put the -15 AWAY when you want to radar something.

I think your statement is quite accurate. I think the lighter and shorter the barrel, the worse an A/R will perform against a similar weight and barrel length bolt gun. Things really change when the weight of the A/R is increased and the barrel becomes heavier and longer, regardless of price. Even a budget-priced long, heavy barrel will shake things up a lot for an A/R. Add a great barrel, trigger and properly tuned, the A/R's can hold their own with the "majority" of bolt guns that tend to shoot around 1/3" MOA or more - for which a lot of shooters would be pretty happy, I think. Unless folks are willing to go the extra mile on brass prep, they will likely never get great SD's out of a .223 A/R. as opposed to a bolt gun. Getting A/R's to shoot under .200"-.250" is going to be pretty rare for most owners, whereas a reasonably good bolt gun might do that.

 

[Dwubyd]

I am still working on this project. The next step is a smaller bushing and mandrel to see if that improves SD through more consistent neck tension.

I have also changed to thinking about SD rather than ES, because it is somewhat independent of sample size.

I have bedded the chassis after finding some concerning issues with the chassis/action interface. I also noticed the point of aim appeared to be moving, something that I have noticed with other rifles and that has been rectified by bedding.

Since getting my borescope (which I highly recommend), I have improved my cleaning techniques. I tried ThorroClean, which worked great. I needed two applications and some Bore Tech copper remover rather than the recommended one application, but it has left the barrel very clean. Next step is to get some Bore Tech carbon remover to tackle the remnants of the carbon ring.

 

[Fire Dog]

I am still working on this project. The next step is a smaller bushing and mandrel to see if that improves SD through more consistent neck tension.

I have also changed to thinking about SD rather than ES, because it is somewhat independent of sample size.

I have bedded the chassis after finding some concerning issues with the chassis/action interface. I also noticed the point of aim appeared to be moving, something that I have noticed with other rifles and that has been rectified by bedding.

Since getting my borescope (which I highly recommend), I have improved my cleaning techniques. I tried ThorroClean, which worked great. I needed two applications and some Bore Tech copper remover rather than the recommended one application, but it has left the barrel very clean. Next step is to get some Bore Tech carbon remover to tackle the remnants of the carbon ring.

I might suggest that if you have a pronounced carbon ring to try and leave a patch soaked with Bore Tech C-4 carbon remover just jammed into the neck-bore transition area for at least 4 hours or even up to overnight.
I just put the patch on a jag and as I feel the patch tightening up as it is squeezed down into the bore just leave everything there with the cleaning rod hanging out the back though I suppose you could try to unscrew the jag from the rod and then later attempt to screw the rod back on the jag but for sure you will need a good bore guide to get the alignment right. {Suggest Possum Hollow}
After the long soak push it all the way though the bore and go for a bore brush with more C-4, nylon or brass, and give the bore about 10-15 strokes. Clean patch or two then check with bore scope, should have resolved the issue. I have found the Iosso blue brushes {stiffer/tighter and more durable} to be better than the Bore Tech ones and though they look to have a brass wire core, Bore Tech Cu2 & Eliminator will not eat them.
I wash my bore brushes out with hot water and a few drops of dish detergent and an old tooth brush. You defiantly will want to do that to the Bore Tech ones as their wire cores will rust otherwise.

 

[Fast14riot]

How many places do they pay out for best chrono numbers at your local matches?

 

[jelenko]

To fast14's question, is your quest to improve performance in matches or a personal quest just to get a lower/small SD?

 

[BoydAllen]

Thanks guys.

Sherm, what I meant by "neck tension is sorted" is that when I got the rifle it came with 300 brass that had neck tension of around 6 thou. I bought a larger bushing to reduce the neck tension to 1.5 thou, which should eliminate that as a potential problem.

I hear what you are saying about believe the target. Of course, at the end of day that is what actually matters. However, as you say a 50 ES is a bit high, so my goal is to get that down, and then I will try varying seating depth and amount of powder.

I am shooting Monday, so I will report back after that.

From a lot of experience with the most accurate short range benchrest cartridge, I can tell you that to get the best accuracy different powders require different amounts of neck tension. This is not often discussed on forums, but it is not conjecture, having been tested with suitable equipment.

 

[Dwubyd]

FireDog - I have my removed almost all of the carbon ring, but I do want to try your suggestion with Bore Tech carbon. I have it in the shopping cart...
Fast14 - good question.
Jelenko - my quest is to go past what is required for PRS, so I am going for low SD as a step toward smaller groups.
JFrank - I plan to try different bushings/neck tension. I have another bushing and a couple of mandrels on the way
BoydAllen - are you varying neck tension by varying the mandrel size in the final step of brass prep? I am using a Redding FL bushing die followed by a mandrel.

I had a very interesting conversation with a bloke who knows a bit. His recommendation was to aim for 0.002" of sizing when I size the necks down with a bushing, up with a mandrel and the same for neck tension. The suggestion is that if you have less than 0.002", say 0.001" you may not get consistently past the yield point of the brass. It was also something to do with if you deform a metal to a point, then push it in the opposite direction it will move more easily to begin with. If my explanation seems unclear, it is because I am unclear about how this works!

 

[DHD]

How many places do they pay out for best chrono numbers at your local matches?

It should be a side match. The bullet has to hit the target, 10 shots, with extra points if you have receipts for all of the equipment you bought to get there, and group size as the last and lowest points added.

Not being serious!

 

[Dwubyd]

Update: The bedding did not make an apparent difference.

Paying attention to bushing and mandrel sizes seems to have reduced ES to 25-30 for 5 shot groups. That is actually quite an improvement. I am sizing the necks in two steps: 249 then 245 followed by a 2215 mandrel. I found that if I sized a fired case down to 245, the neck came out flared. Out of a 245 bushing it would be 242 in the narrowest part of the neck (the middle) and 244 at the flared end. Weird. I did some research and this occasionally happens when you size the neck down too far in one step. I am starting at 255, so sizing to 245 is 0.010" and apparently that is too far. I don't know whether the flaring was happening before - I never noticed it.

Next I am trying a hotter load: 26.0 grains 2206H for 2980fps. I will test seating depth and see if I can get some good groups.

At some stage I will give up and get a new barrel. Not sure whether to stay with 223 Ackley or move to 6 Dasher. The move would mean new dies, brass and bolt. At this stage I am leaning towards staying with 223AI even though 6 Dasher is the go to calibre for PRS, and for good reason.

 

[Dwubyd]

The seating depth test worked okay, but it looks like there are more significant factors than seating depth that are affecting accuracy.

I did have some success with reducing SDs. SDs for 4-5 shot groups are mostly in the 10-15 range with some well below 10.

The steps that helped were:
1. Sort out the right bushing sizes, mandrel sizes and sizing process
2. I weight sorted cases, but after testing I have concluded that it is sufficient to eliminate very heavy or very light cases.
3. My testing suggests that having a long case length such that the neck comes too close to where the carbon ring would form increases SD. Slightly shorter cases gave lower SDs. I am not convinced on this one. Just a suspicion.

My other conclusion is that the barrel is done. I am never going to get good accuracy out of it. Off to the gunsmith it goes!