Loading for precision

[Crotchrocket]

So I just shot my first reloads at the range and I'm wondering how you guys sneak up on the most accurate loads.

I started with Sierra Match King 69GR bullets which were the most accurate factory ammo I tested in my gun using the federal gold medal match. Then I got a deal on Ramshot Tac and used CCI #41 primers. This is in .223 BTW..

The manual I have says a 69GR bullet with Ramshot Tac in .223 should be between 21.9gr and 24.3gr of powder. So I loaded 22gr to 24gr in .4gr increments. 22, 22.4, 22.8, 23.2, 23.6 and 24gr. I didn't load at 24.3gr because this was my first time and didn't want to blow my face off... This is in a .223 wylde chamber though so I am assuming I could get away with a little more. The 24.0 loads showed 0 signs of over pressure and you could not tell the difference between those and the 22gr loads on the case. The 22gr loads were noticeably lighter recoil though. I loaded 10 of each and did a light crimp using the lee factory crimp die.

My results were that the 22.4gr and 23.6gr showed the tightest groups, but now looking at it those were both the targets in the middle so maybe my aiming had something to do with it.... as it seems odd they are the two targets that happen to be in the middle.. For the lower group I noticed the bullets were all tracking right so I adjusted my scope 1/2 MOA left to get them more on center. I had some 75gr Hornady black and wolf gold 55gr to use as a comparison for my personal shooting ability. Since these were all shot out of the same gun by the same person on the same day in the same conditions we can't say that the groups with the 55gr wolf gold are the shooter or the gun when the hand loads and match ammo grouped much better.

Anyways just wondering how you guys sneak up on the most accurate load. Should I have run a smaller gap between the powder charges to begin with? If 22.4gr is precise should I try 22.5 or 22.6 and 22.3 and 22.2 or does it not really work that way? Would loading hotter be better for maintaining velocity? Should I try working in the 23.6gr range? I didn't have Chrony so not sure what the actual difference in velocity is. The book says out of a 24" barrel there is a 250 FPS difference between min and max loads.

The Matchking bullets are expensive, it costs about as much as buying cheap complete ammo as it does to reload with the SMK bullets so I got some Z-MAX 50gr bullets at half the price and will be working up some loads on those. I have read those are either the V-MAX or A-MAX with a green tip..

 

[akma]

The Hornady headspace and bullet depth gauges are great tools to produce accurate loads. They allow repeatability. I like Varget in my 223.

 

[Crotchrocket]

The Hornady headspace and bullet depth gauges are great tools to produce accurate loads. They allow repeatability. I like Varget in my 223.

This is an AR15 so if I want to use the rounds in magazines I'm locked into a length much shorter than the optimum length. These rounds were all at 2.260 OAL.

I'll try some Varget.

 

[Tallen]

I've only reloaded ammunition since 2011 and haven't done much lately so take my words with a salt shaker. Some of the more experienced reloaders may have better advice but this is my experience:

There is no good formula for reloading. The manuals offer guidelines for safety, not for precision. Getting good results is like computer networking... more black magic than science. The factors I ran into and attempted to compensate for are the following:

Barrel harmonics I: If the barrel is not free-floated, meaning nothing else is touching the barrel except at the receiver end, then repeatability outside of a bench-rest is nigh impossible. Example: my Kel-Tec RDB's barrel is attached to the rest of the rifle at 2 points besides the receiver, and can exhibit vertical stringing due to variance in the way I'm holding it, even sitting at a bench. This is not an issue if the barrel is free-floated. Note that a gas-operated semiautomatic rifle can never be free-floated because of the gas block, but a free-floated handguard can reduce this issue and make shots more repeatable.

Barrel harmonics II: When the powder is ignited, shock waves are sent down the barrel, changing both the outer diameter and the bore diameter minutely. These waves start at the firing chamber, go to the muzzle and back. These waves are ongoing when the bullet exits the muzzle. The bore diameter when the bullet exits the muzzle affects its flight path. The tightest groups happen when the bullet exits when the bore is at its narrowest, but you can still get repeatable results as long as the bore is in the narrowest half of its range. I think this is where most of the impact from differing powder charge size can be seen, because you're changing the acceleration of the bullet without changing the length of the barrel. Harmonic theory suggests there are a number of "sweet spots" at different powder weights, where the bullet is exiting the muzzle when the bore is close to its narrowest point, and I think this is what you were seeing at your 22.4 and ~23.6 charges. You can read more about these kinds of harmonics elsewhere but the key is repeatability in your powder weight which is why a good scale is so critical. A flyer could happen just because of a slightly high or low powder charge.

Bullet jump: When a cartridge is seated in the chamber, there is usually a gap between the bullet and the lands/grooves of the barrel. A longer throat length means a longer jump, and a shorter throat means less or no jump. This also varies depending on the bullet you use and how deep you seat it in the cartridge. How much jump from the cartridge to the lands/grooves is ideal? It varies rifle to rifle with little rhyme or reason. Some rifles group better with a longer jump and others with a shorter or no jump - and from what I've read this can apply even to the same consecutive rifles on a production line. By and large a shorter jump (~0.001") seems to be preferred but you have see what works for your rifle. Example: my RFB has a longer throat than most .308 rifles and I can't actually seat most bullets (Hornady A-maxes for instance) to get a close jump, resulting in poorer than expected grouping - even when I seat them to barely fitting in the magazine. However, those groups close right up if I use Speer 170gn round-nose bullets intended for a 30-30 rifle because the ogive is much shorter, effectively closing the gap to the lands/grooves without increasing the COAL.

Heat: As you shoot more, the barrel gets warmer and its physical characteristics change. Different rounds work better for cold barrels than for hot barrels, so tune your hand loads based on how you expect to use your precision rounds. If you expect to fire lots of them in a short amount of time, fire a bunch of factory ammo before your hand loads and then while testing mix up the order of the cartridges so the heat level is approximately the same for each batch. If you just expect to fire a small amount from a cold bore then tuning your ammo is going to take longer because you'll want to let the barrel cool off while tuning.

Summary: make sure your rifle barrel is supported the exact same way every time when testing, or free-floated if possible. Find those sweet powder spots, then play with the cartridge overall length until you're happy. Lastly, keep your barrel at the temperature you expect to fire your hand loads at when testing them.

 

[mac1911]

Your picture is not there ? Stick to one bullet and one powder for the time being. If the SMKs are to costly use hornady or Nosler
You can find good accuracy nodes using the OCW method.

http://optimalchargeweight.embarqspace.com/#

We all like small little groups but some powder charges do funny things.

One thing I learned to do is forget about adjusting your scope. It adds a factor into it. Get your scope zeroed to withing a inch or so of your aim point and shoot for groups. Once you find a load you like you can zero your scope from there.

 

[akma]

This is an AR15 so if I want to use the rounds in magazines I'm locked into a length much shorter than the optimum length. These rounds were all at 2.260 OAL.

I'll try some Varget.

I hear you. But once you try some you won't go back.

 

[highscore]

This is an AR15 so if I want to use the rounds in magazines I'm locked into a length much shorter than the optimum length. These rounds were all at 2.260 OAL.

I'll try some Varget.

Varget is probably the most widely used powder for the AR223, at least with the highpower group. If your worried about velocity go with Reloader 15 which will get you a bit more speed. I use Varget for most of my service rifle shooting, and suggest 24.0-25.0 grains under the 69 grain Sierra, start in the middle and you'll be fine. Your OAL is spot on so for mag length, don't change it. I've gone down to 2.245 and did't see any change in anything that mattered to me. If your looking for accuracy, don't use any of the cheap primers, I always used Fed Match which have a reputation of slam firing ( never happened to us) but when Federal came out with the match AR primers, I changed to them for new purchases. If accuracy is what your after, try some 77 Sierra's. 23.8 grains of Varget is my favorite load. Everything I'm talking about is for a 20" service rifle with a Wilde chamber and twists from 6.5-7.7

 

[Crotchrocket]

Varget is probably the most widely used powder for the AR223, at least with the highpower group. If your worried about velocity go with Reloader 15 which will get you a bit more speed. I use Varget for most of my service rifle shooting, and suggest 24.0-25.0 grains under the 69 grain Sierra, start in the middle and you'll be fine. Your OAL is spot on so for mag length, don't change it. I've gone down to 2.245 and did't see any change in anything that mattered to me. If your looking for accuracy, don't use any of the cheap primers, I always used Fed Match which have a reputation of slam firing ( never happened to us) but when Federal came out with the match AR primers, I changed to them for new purchases. If accuracy is what your after, try some 77 Sierra's. 23.8 grains of Varget is my favorite load. Everything I'm talking about is for a 20" service rifle with a Wilde chamber and twists from 6.5-7.7

I've got 1:8 18" HBAR with brake.

 

[Mountain]

That twist rate should be good for 69's.

TAC, from what I have read, is good for velocity but not the most accurate powder. I'm a big fan of Varget, but in larger calibers. The only reason for that is because the Varget rod shape powder is a little difficult to throw consistent weights from the powder measure. I have a Harrell benchrest measure, so it's a pretty good one. I have achieved as good or better groups with Benchmark, a much finer powder. The main benefit to Benchmark is that my 'throws' are very consistent at the small .223 charge weights.

I have a Compass Lake barrel in my service rifle. The Compass Lake chamber is quite close to the Wylde chamber. It shoots MUCH better than I do. With the Benchmark powder, BR4 primers, and 77's it's pretty much a no-brainer to hit sub MOA groups at 100 and sub 1/2 MOA with Berger 80's via careful shooting from the bench with a scope.

 

[Warm_Garand]

Yes, good bullets are expensive.

At what distance are you shooting?

If you're not shooting long distance you're probably wasting your money on the SMK's.

Hornady 55's W/C are pretty accurate at 100, and they cost about 7.5 cents per.

The soft point bullets have a reputation for accuracy as well, apparently .75 MOA is fairly common.

You might want to consider going in that direction, if cost is a huge impediment.

INRE: TAC, I seem to recall reading that TAC shoots best at MAX load.

Are you an experienced (and attentive) enough reloader to feel comfortable working consistently at MAX?

 

[mac1911]

That twist rate should be good for 69's.

TAC, from what I have read, is good for velocity but not the most accurate powder. I'm a big fan of Varget, but in larger calibers. The only reason for that is because the Varget rod shape powder is a little difficult to throw consistent weights from the powder measure. I have a Harrell benchrest measure, so it's a pretty good one. I have achieved as good or better groups with Benchmark, a much finer powder. The main benefit to Benchmark is that my 'throws' are very consistent at the small .223 charge weights.

I have a Compass Lake barrel in my service rifle. The Compass Lake chamber is quite close to the Wylde chamber. It shoots MUCH better than I do. With the Benchmark powder, BR4 primers, and 77's it's pretty much a no-brainer to hit sub MOA groups at 100 and sub 1/2 MOA with Berger 80's via careful shooting from the bench with a scope.

This is where the OCW system plays out. It finds a nice node of accuracy and range of powder charge that does not change your POA/POI so you can end up with a charge weight that can vary and still put you on target where you expect to go.

 

[DW357]

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[highscore]

I've got 1:8 18" HBAR with brake.

With the shorter barrel, you could use the Reloder 15 for higher speeds. It's even cleaner than Varget. Your are talking about precision so using quality components is not a bad way to go. Some get "acceptable" accuracy from lighter bullets some of which are pretty inexpensive (62,55) but if your shooting distance, I wouldn't use them. Acceptable to one person loading up a 30 round mag and "hitting" his target isn't the same as shooting small groups at distance.