I am loading 124 gr truncated cone FMJ amo for accuracy.

In order of importance what are the three factors that most affect accuracy?

FWIW I'm using 124 gr RMR matchwinner bullets.

Thanks for sharing your wisdom and experience.

Consistency is the 3 most important factors in making accurate ammo. Consistent components, consistent reloading equipment and consistent methods.

Edit 1: I'll add that testing that bullet and others in your intended firearm is probably a good place to start, once you have the consistency angle worked out. You could look at some of the testing long range rifle shooters do to get an idea. That bullet may not be ideal for your barrel.

Edit 2: The more I think about this, the more that could be said. I'd look at the Optimal Charge Weight method the precision shooters use and do something along those lines.

How much accuracy do you want, by the way?

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Just Say No - To Social Media

...I find that heavy, slow moving bullets loaded with Acc #7 give me the best accuracy, but I haven't tried a lot of combinations as most of my practice is defense oriented.

Choice of bullet profile and construction seems to make a difference to many people here with jacketed RN types being favored. SWCs are not favored. Neither are plated or coated bullets. Honestly, I'm not good enough to tell the difference.

I suppose number three would be good reloading practice.

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"He was kinda funny lookin'"

I've found the 3 most important factors for accuracy are good technique, Good eyes, and a consistent smooth trigger stroke. As for ammo, just about any will made cartridge will perform better that what nearly all of us are capable of doing standing on our hind legs.

The top 3 in no particular order are Time, Money and Energy.
I guess the first question is- what are your goals?
Is this for competition, SD, plinking?
You could get pretty crazy chasing accuracy.
The key is always reducing every single variable possible.
You could weigh measure and sort your brass and projectiles.
Trim brass. Put the components outside of your acceptable range into the “fouler” pile.
Hand prime, hand measure powder. Trim brass.
Find out what components shoot most accurately then using that exact combo adjust your OAL slightly up or down and see if it helps accuracy and for your intended purposes.
I would recommend not sticking to just one projectile as well.
I didnt even get to chrono’ing your loads for consistency yet.
Some guns and barrels shoot well no matter the load. Some shoot poorly no matter the load. Barrel swaps and gun swaps are to he expected.
Its a huge rabbit hole. Hope you have lots of time and your endeavors are worth your efforts.

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Romans5:8

Match the bullet to the throat of your barrel shape wise.

Set the oal of your reload to the throat of your bbl.

Use the correct expander die for the length/diameter of the bullet you plan on using.

1) consistency of your reloads
2) Practice
3) MORE Practice

Step one ... the plunk test.
This is where you set your crimp just tight enough to pass the plunk, perhaps an extra half a tickle to ensure function.
Beyond this, you are needlessly deforming the bullet.

Step two ... COAL.
Set your seating depth to recommended COAL.

Step three ... multiple powders at multiple weights, keep good records and work from the most accurate for each.

Step four ... adjust your COAL to make one test batch about .005 short and another .005 long. test these against the recommended COAL, observe for improvements. Use that data to further experiment to find an optimum COAL.

Step five, revisit charge weight with that optimum COAL for further tuning.

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it just needs more voltage

For jacketed bullets in 9mm I don’t find a ton of difference from load to the next when using appropriate bullets and a reasonable powder charge. Accuracy comes from lots of practice and a decent gun.

With something like .38 special Using lead bullets, the components selected and reloading techniques become more important.

"Your" 9mm pistol is not "My" 9mm pistol so my data might not work for you.

Your pistol barrel might like under sizes bullets?
Hate lead and love plated bullets ?
Do best with maximum fps instead of target loads?

Just use what powders you have and work up some loads.
Finding a accurate load is a **** shoot.
You might roll "snake eyes", "Box cars" or that lucky Seven, at any time.

Good luck.

Way back in the last century, the DOD did a project to improve accuracy and lethality of the 9mm service pistol round. After considerable experimentation, they discovered that a truncated cone HP was the most accurate. A non HP version was more accurate than the typical RN ball and also improved tissue damage/lethality without violating any aspects of the Laws of War.

Having blown the taxpayers money, the DOD then stayed with the JRN. While that form is in the official STANAG 4090 document, the RN form isn't mandated. Hornady made all the test bullets and used what they learned to improve their product line.

Now, the question is: just what's your accuracy standard? At the top end, I'd give the Hornady HAP bullet a try. FWIW, I've come very close to 1 inch at 25 yards with the Berry Flat Point from prone with a red dot. Don't recall if it was 115 or 124 gr. They also make a Target Hollow Point, but I haven't tried it in 9 mm.

I had zero luck with the Berry’s 124 gr HP. In fact, such bad luck that I wonder if I just got some from a bad batch. Lacking a Ransom rest, I used to shoot quite a lot from prone to test accuracy. It was a confidence builder.

I’d say it’s pretty hard to pin down three things that are most likely to affect accuracy across the board in any particular caliber. In general terms, “quality never goes out of style.”

I would want a baseline to have some idea what my pistol (with me shooting it) is likely to do. You might start by getting a couple of boxes of good quality factory ammo and firing some control groups, being careful to be very consistent with your technique. Keeping good records is necessary.

In 9mm factory ammo, my first choice is Federal 147 gr. FMJ-FN, but some guns prefer lighter bullets, so I’d also be looking for a high quality 124 and 115 grain factory load, too. It’s nice to try to work with ammo from the same lot, so if you find something that works for your baseline load, get a reasonable supply of it.

Once I had some idea what weight and shape of bullet the gun seemed to prefer, I’d go on from there. I’ve had a hard time telling a difference with various primers in 9mm. A chronograph may help you sort that out, but probably only if you’re working with new brass. I think the powder selected often has more effect on accuracy in service grade pistols than a particular primer does.

It’s not at all unusual for a load to shoot very well at pistol (short) range that the chronograph indicates is not optimum, and sometimes one the chronograph shows to be very consistent does not shoot all that well. One never presumes the chronograph tells the whole story.

When I worked up loads when I first purchased a 9mm. Using powder coated and Jacketed JHP's. OAL (seating depth), amount of crimp, bullet weight, powder and charge weight. This "assumes" you have fully prepped your brass, (trim length uniformed, flash hole de-burred, primer pocked uniformed). Then selecting at least 3-4 different powders and (from a loading manual) work up each load from the middle of the given range .2 gr increments up to the max load. Make up 15 rounds of each grouping, and shoot from the specific gun from a sandbag rest 3 5 round groups. Do this with each of the selected powders. The most consistent grouping will ususlly become evident.

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H Richard
SWCA1967 SWHF244

Consistency of hold, timing your shots to the same point when you wobble and breathing are among the top three personal guides.
Mechanical to the ammunition are consistency of cases as H Richard said above and to include same manufacture, weight sorted quality bullets and powders you have tested to your accuracy standard. I get the best results with faster powders but only shoot cast and no longer shoot competitively except against myself.

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Front sight and squeeze

The first rule of purchasing bullets, is to select a company that doesnt sell more varieties of "seconds" and "oops bulelts" where the manufacture states and actually brags that:

1. they arent sure of the actual bullet weight or measurements
2. didnt KNOW the machines were out of "adjustment" until after they had made 1,000 pounds of bullet and actually started checking for quality.

How can you load accurate ammo when you can't even spell it ?

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Grumpy Old Man With a Gun

What I have found are:
A known accurate gun
A JHP bullet of 115-124gn bullet
A reasonably slow powder from Silhouette/Power Pistol to AA7 or, reportedly from some guns, a fast powder from Bullseye to 231/HP38
The longest cases you can find. For a single gun where you do NOT load 9x21, you can buy 9x21 cases and trim them to your barrel's head space.
Get a match grade slow twist barrel (say 1:25 to 1:33).

THR Group Project - PISTOL - Advanced Reloading Concepts and Discussions | The High Road

Precision pistol shooters test gun and ammo in a machine rest. That's where I'd start. Find some match ammo and see what your gun will do. Then start the reloading process. Not as much fun as shooting.

The fantastic plastic guns reportedly don't do as well from a machine rest as a metal frame gun. The difference is believed to be related to flexibility of the frame.

Something I don't hear mentioned much, and this might not work with 9mm reloading, is indexing.
When I shot in Cast Bullet Association Matches I would index all my reloading operations. Every case would go into the press with consistent headstamp orientation for every operation (sizing, flaring, seating, crimping). Every boolit would get seated consistently according to parting line orientation. Same for running them through the lubrisizer.
Every round would get chambered according to headstamp orientation.
I used a Ruger 30-06 M77 sporter (with the ugly black plastic embarrassing Mattel stock) against many shooters using custom benchrest equipment.
I never won a match against them, but I never came in last, either. I held my own.

If someone really wanted to wring-out the best accuracy from their 9mm........and had a lot of time on their hands......

It all depends upon your standards. What distance do you want to test and what 10 shot or so group sizes do you hope to achieve

For Handguns : 25 Yard Precision ( Bullseye) Match .

Good bullets ... that your gun likes & shoots accurately... Tested .

Consistent charges of a Bullseye like powder ... Bullseye is usually best.
But the load must be liked by your gun ... use a fast powder and test them .

A quality Trigger Job by a Quality Gunsmith ... Clark Custom Guns put one of their Target Trigger jobs on two revolvers and a 1911 that did more for my NRA Bullseye ( Precision ) Match scores than anything else I ever did at the reloading bench ... spring swaping and polishing is ok but a Professional Clark Custom Triger Job has that beat Seven Ways To Sunday ... and puts a Smile on your face !

Goog quality bullets , Bullseye powder and CCG Target Trigger job
is my recipe for Accurate Handgun Shooting !
Gary

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Certified Cajun
NRA Member

Wondering what weapon you are trying to get all this accuracy from and what kind of accuracy are you expecting? Asking because some are not inherently accurate no matter what you do.

My Beretta likes .357 bullets. Sig too.

Was hitting a 9" pie plate at 100yds (at 50%) with a CZ in 38super (open sights).... using 135gr RN .357 bullets.

Another B/E user here. Sometimes I find a load that's more accurate than Bullseye, but it's a lot of work and better is almost never very much better. So, if you want just one powder to try, I'd say this is it.