Some "Advanced" Questions About Hand Loads

[JackEllis]

I've developed hand loads for my .223 and .243 (both Tikka T3 Lites with 20" barrels) that work and produce groups on the order of 1-1 1/4" at 100 yards with acceptable velocity. They're good enough for hunting but I would like to see what I might be able to do in the course of the reloading process with a reasonable amount of effort to close the groups a bit and get more consistent muzzle velocities. Ideas like swapping barrels and stocks, turning cases and weight sorting cases and bullets are off the table for now.

The two things I've noticed are:

A) Relatively small vertical spreads with somewhat larger horizontal spreads. I do my testing with little or no wind and what I remember reading is that barrel whip affects horizontal spreads rather than vertical spreads so I'm puzzled by this source of variation. The rifle is supported in front with a sandbag and in back by a bean back I hold and squeeze with my left (non-shooting hand) to keep the reticle on the bullseye. Triggers are adjusted to be as light as possible and I squeeze very (perhaps too) slowly but I can't rule out bench technique either.

B) Occasional large variations in muzzle velocity. This was particularly apparent with a .223 load using 35 grain Hornady NTX bullets with IMR4198, where the groups were surprisingly consistent size wise but standard deviations were on the order of 2% and extreme spreads on the order of 4%. I measure each charge using a digital scale from Cabelas. It drifts but I check the charges pretty carefully. All cases are Lake City once-fired brass with CCI small rifle primers.

Like I said, I'm willing to tinker with the reloading process but I can still hit what I'm aiming at.

[jericho89]

To get better accuracy you need to do a few things:
Use the same brand and batch brass (weighing them in batches helps)
Size all the brass, trim them to the same length, and full length size them.
Weigh each powder load by hand so that they are the exact same
Weigh each projectile and make sure they are the exact same weight
Make sure that each round is the exact same length

Other things you can do are play with the crimp of the bullet and also you can play with the over all length of the projectile. You would want the projectile to be as close to the rifling as possible.

[desert dog]

A few things:

1) learn to find an accuracy node. Plenty of online tutorials and Youtube videos explaining this better than I am able to. This is probably your main issue. Unless you just get extremely lucky, you gotta put in the work to get the load.

2) Dump the Cabelas digital scale. You will never achieve extreme accuracy with inconsistent equipment. Your consistency will probably double with an inexpensive 505 beam scale.

3) Vertical stringing can also be caused by a hot barrel. That little 6 lb T3 probably need a lot of cool-down time between shots.

4) Before shooting non-lead bullets like your NTX, you MUST completely scrub your barrel and remove ALL traces of copper from previous bullets, then start over re-fouling the barrel with the NTX. I found this to be a VERY important step before working up loads with Barnes and GMX bullets.

5) Your bullet may not like your powder, or, your gun may just not like the NTX. I have prenty of barrels that don't like certain bullets.

[jimmykan]

T3 Lite rifle have sporter contour barrels. Groups will open up as the barrel heats up. If you could limit the rate of fire to 1 shot every 2 minutes, so that the barrel never gets too hot to touch, I think you'll see tighter groups.

Aside from that, here are some things to try:

Consistent ignition: Try different primers, specifically match primers such as CCI BR2/BR4 or primers that are considered milder than average such as Wolf/Tula KVB-556M or Sellier & Bellot.

Consistent brass: Uniform case capacity, uniform primer flash hole, uniform neck tension. If you don't want to sort or turn or anneal your brass, try some Lapua brass. The neck of any brand of brass will begin to harden after the second firing, and you will notice more spring-back after sizing the necks, and harder / inconsistent effort required to seat bullets. Annealing resets the neck's grain structure, makes sizing and seating more consistent, and also seals off the chamber better during combustion.

Bullet seating depth: The Hornady NTX bullet has a secant ogive, and may be more sensitive to seating depth than tangent or hybrid ogive bullets. It does not always mean they prefer to be jammed into the rifling, but there will be a seating depth "sweet spot" where groups will tighten up.

Berger Bullets - Setting Up Your Loads For Optimum Accuracy

Berger Bullets - Getting The Best Precision And Accuracy From VLD Bullets In Your Rifle/

[rsrocket1]

jerocho is very correct.
I've found that my accuracy goes way up when simply using the same brass. I went from 2 MOA down to 1/2 MOA just by exclusively using some of my once fired PMC cases rather than bulk range pickup.

Hand trickling down to the tenth of a grain helps but like desert dog said, if you find an accuracy node there will be a point in your load workups where a group will shrink and stay the same over the span of +/- 0.2g or maybe more.

Read up on Optimal Barrel Time. If you have Quickload, you can get close to an OBT very quickly and work your way to a very consistent group where you can tolerate variances in charge, seating depth due to differences in bullet weight and even case volume due to differences in case brands.

[Whiterabbit]

My suggestion for your #2

Recalculate your SD and ES in your strings, and track ES as a function of SD. What is ES, double SD? Triple? Quadruple? You don't have to answer that in this thread.

See if you can find out what competition shooters are getting for numbers. Are they double, and you are at 4x? That means your ES is dominated by small numbers of huge flyers while most are near the baseline. That implies something in your reloading is out of control. A scale that drops too much every now and again? a couple pieces of over-stressed or over-trimmed brass that need to be culled? Bad QC from your bullet supplier? Flash hole non-uniformity? etc etc etc, you get to be the investigator.

But if your ES is (for example) double SD, and competition ES is double SD, then you are within your controls, and there isn't a problem with individual rounds causing the flyers, but rather something systemic within the population of loads. Wrong OAL, wrong powder choice, wrong primer, etc etc.

That is the strategy I would employ if I were looking to learn something from my ES/SD, as well as tighten things up a little bit in the most efficient way.

[Whiterabbit]

I got a massive reduction in horizontal by switching primers. Don't ask me by what mechanism this works. I have no idea. But I tested ABAB with significant results, so I just use primer B now. That may not work for you at all. But it might.

Group size is also affected by changing OAL, but won't affect velocity much (ie won't impact vertical-due-to-velocity-variation). So you might try to tune your horizontal via OAL.

[Rockdoc173]

Have you tried a quality factory load to see what you'd get?


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[rsrocket1]

I got a massive reduction in horizontal by switching primers. Don't ask me by what mechanism this works. I have no idea. But I tested ABAB with significant results, so I just use primer B now. That may not work for you at all. But it might.

Group size is also affected by changing OAL, but won't affect velocity much (ie won't impact vertical-due-to-velocity-variation). So you might try to tune your horizontal via OAL.

Different primers have different strengths and different burn durations. That doesn't mean a hotter or longer burning primer is better, it just means it may affect the ignition of the powder differently. Ball powders tend to ignite slower (less surface area per weight) but they are intended to perform that way.

Same goes for OAL, a shorter OAL will drive pressures up. Sometimes it makes for a more consistent burn, sometimes it causes powders to behave less consistently.

The only way you can know what works with your combination of powder, primer, bullet, case and gun is to try them all and see what variable controls what by changing one thing at a time and noting the effect.

I also agree that flyers must be accounted for unless you are shooting in a contest that allows throw-outs. You don't get that chance in a one shot hunt.

[glassparman]

As rsrocket1 mentioned, you can now go up and down in 10ths of a grain to find that sweet spot that gives you the tightest group. Where 26.4 might be the best for one, it will most likely change on another rifle exactly the same. Every rifle has its sweet spot, you just gotta find it. Published loads will get you in the ball park, now you gotta dial it in by playing up or down some. You would be surprised how many times I have had to back off the amount of powder to find that spot.

As the others have said as well, consistency with components is very important. I ALWAYS use LC military brass for my 5.56 and even then I check the weight to get them as close to the same as possible. I have set aside many pieces of brass because they were too far out from the batch I had started.

Even things like concentricity. I use a Zip trim and many times I put a piece of brass in and when I pull the cord, the brass has a wobble to it. This tells me that it is slightly out of round because the base is off some. Neck tension, bullet depth and many other things will cause some deviation. I've noticed that sometimes the projectiles I bought seemed to be slightly different. The seating depth it took to get the case mouth dead in the center of the cannelure is sometimes different. This tells me that the quality on the bullets is not perfect either.

Just take the time to look at all factors and go with consistency.

[JackEllis]

Thanks for all of the responses and suggestions. I'm aware of some (I used the same make of brass for my test loads) and will think a bit about some of the others.

I've been choosing loads with smaller vertical spreads and acceptable (1-1 1/4" group sizes) over the absolute smallest group size, especially for the .223, because I suspect I may be moving the rifle slightly from side to side.

I haven't tested factory ammunition but I have several different factory loads including Australian Defense Industries (supposed to be very accurate) for the .223 and when I first got the .243, I tried two different Winchester loads that were a bit better than mine have been. Testing factory loads been on my list of things to do and probably needs to move to the top now.

The .243 load uses Remington 100 grain Remington Core-Lokts. I wasn't able to find a recipe for that specific bullet, let alone that bullet and powder combination, so I started with data from Hodgdon's web site for Speer 100 grain ballistic tips and worked up from their recommended starting load to just below their max recommended load, watching for pressure signs. I 've got that bullet seated roughly 70 thousandths off the lands based on a Hornady headspace gauge and I guess the next step is to try loading them a bit longer.

Someone posted a poll asking which powders people use for .223. I was a bit surprised to find IMR 4198 was not on the list, because my Hornady load book says I need smaller amounts of that powder for a given velocity than just about any of the others. Am I missing something here?

Some of you mentioned barrel heating. I will shoot as many as three in a row before the barrel becomes warm but not too hot to touch. When I tested yesterday, temperatures started out in the 30s and got up to perhaps the high 40s. I try to bring two calibers to test so I can trade off, realizing that I introduce another variable if I shoot one with the barrel cold and two others where the barrel is warm but not hot.

One followup question if the respondent wouldn't mind:

Jericho89:

Make sure that each round is the exact same length

Exact as in to the thousandth, or "exact" to within say 10 thousandths? I've noticed small variations in OAL that have to be due to tiny variations in bullet shape.

[NorCalFocus]

Thanks for all of the responses and suggestions. I'm aware of some (I used the same make of brass for my test loads) and will think a bit about some of the others.

I've been choosing loads with smaller vertical spreads and acceptable (1-1 1/4" group sizes) over the absolute smallest group size, especially for the .223, because I suspect I may be moving the rifle slightly from side to side.

I haven't tested factory ammunition but I have several different factory loads including Australian Defense Industries (supposed to be very accurate) for the .223 and when I first got the .243, I tried two different Winchester loads that were a bit better than mine have been. Testing factory loads been on my list of things to do and probably needs to move to the top now.

The .243 load uses Remington 100 grain Remington Core-Lokts. I wasn't able to find a recipe for that specific bullet, let alone that bullet and powder combination, so I started with data from Hodgdon's web site for Speer 100 grain ballistic tips and worked up from their recommended starting load to just below their max recommended load, watching for pressure signs. I 've got that bullet seated roughly 70 thousandths off the lands based on a Hornady headspace gauge and I guess the next step is to try loading them a bit longer.

Someone posted a poll asking which powders people use for .223. I was a bit surprised to find IMR 4198 was not on the list, because my Hornady load book says I need smaller amounts of that powder for a given velocity than just about any of the others. Am I missing something here?

Some of you mentioned barrel heating. I will shoot as many as three in a row before the barrel becomes warm but not too hot to touch. When I tested yesterday, temperatures started out in the 30s and got up to perhaps the high 40s. I try to bring two calibers to test so I can trade off, realizing that I introduce another variable if I shoot one with the barrel cold and two others where the barrel is warm but not hot.

One followup question if the respondent wouldn't mind:

Jericho89:

Exact as in to the thousandth, or "exact" to within say 10 thousandths? I've noticed small variations in OAL that have to be due to tiny variations in bullet shape.

Get a bullet comparator from Hornady and measure the length from base to o jive. That's a much more consistent way to measure.

[Whiterabbit]

Exact as in to the thousandth, or "exact" to within say 10 thousandths? I've noticed small variations in OAL that have to be due to tiny variations in bullet shape.

No need t otake any of our recommendations at face value.

Of course, you measure!

Load up your next batch, and sort by OAL. Shoot like for like within populations.

No effect downrange? No more measuring OAL differences for future batches.

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Wash rinse repeat for any suggestion any of us make. So measure to the N-th degree and be anal about it. You'll only have to do it once. (unless you get some spectacular results!)

[Whiterabbit]

Some of you mentioned barrel heating. I will shoot as many as three in a row before the barrel becomes warm but not too hot to touch. When I tested yesterday, temperatures started out in the 30s and got up to perhaps the high 40s. I try to bring two calibers to test so I can trade off, realizing that I introduce another variable if I shoot one with the barrel cold and two others where the barrel is warm but not hot.

That's why you shoot random. Even round robin allows for patterns that can muck up your data without you knowing it. Shooting random injects uncertainly evenly (theoretically) in your groups. None will be the best possible, but you pick the best for that day. That way, when you shoot just that load back to back, you see a further improvement in performance.

[J-cat]

Weigh your cases and sort them into 1gr lots. This will ensure their internal volume is consistent.

Get a OAL gauge that indexes off the bullet ogjive. Then find the OAL at which the bullet touches the rifling. Then load different OAL's in .010" increments until you find the most accurate OAL. You can do this by making a FL sized case with a slit cut into the neck to allow the bullet to be seated by the rifling upon chambering.

Large ES can be reduced by using the correct amount of neck tension. Too much tension or too little increases ES. If the bullet seats hard and you are damaging the bullet tip you have too much tension.

Decent ES can be further reduced by trying different primers. Avoid Magnum or military primers unless they are absolutely necessary. Mild primers are best fir low ES.

Finally, make sure you are in the correct pressure range for your load. There are two or three accuracy nodes but the low nodes often come at too low of a pressure and you get inconsistent velocities due to inconsistent combustion. The same can happen at the high node when your pressure is too high. You get pressure spikes which increase ES.