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If you’re starting out shooting in whatever form that can take, such as hunting, competitive shooting, concealed carry/home defense or all of the above, one thing that’s a must is testing your ammunition. If you’re going to use a gun — for any purpose — you have to be able to rely on your chosen round to do the job you need it to do.

Experienced readers are now thinking to themselves, “well duh.” But based on my experience with a lot of new shooters, that’s not as intuitive as you might expect. Most new shooters think that anything on the shelf will work for them.

But just like guns, cartridges are tools that you have to be able to rely on to do their designated job. They need to fire reliably, cycle dependably, hit accurately and – in the case of personal defense or hunting ammunition – produce good terminal performance.

Even among a variety of popular quality ammunition brands and loads, you’ll find some work better in your particular gun than others. Therefore you need to determine what brands and loads work best for you. That way, you can be confident that you can depend on your ammunition come match day, when that whitetail gives you a broadside, or when an attacker gives you no other option.  

That means burning a few boxes at the range to determine what cycles best in your carry pistol, produces the tightest groups from your rifle or patterns best out of your shotgun.

Here are some visual aids that demonstrate to why that’s important.

I spent some time experimenting with a few different loads in my hunting rifle. I’ve had a range of results with a few different loads and bullet weights and I wanted to test some that I’d accumulated to date. I shot them at 100 yards; the point here wasn’t practicing off-hand 400 yard shots. I was seated and it was hot, but not windy conditions.

It wasn’t my best day, but not my worst and I don’t claim to be the best shooter anyway.

I was shooting a Winchester Model 70 .30-06 rifle with a 3-9x by 40mm Tasco scope with a Leupold base and Leupold rings. Sorry for the picture quality and sun glare.

After checking my zero, here was the first brand of ammunition I tested:

This was Federal Fusion 150 grain. This is a good, quality ammo brand that plenty of people shoot well, but minute of barn doesn’t cut my mustard. Never again for me, at least not in this gun.

The second brand was a more premium load:

These were Federal Premium 180 grain Nosler Partition. Partition is a classic; it’s reliable, accurate and deadly. A lot of people depend on it in the field all over the world. If I was determined to only shoot Partition, I’m pretty sure I could dial it in. However, I won’t be and here’s why:

As you can see, cartridge #3 — Remington’s 165 grain Core-Lokt — is noticeably more accurate than the other two rounds from my rifle. All three cartridges are quality loads in different bullet weights that any shooter can buy with confidence and rely on. But as the testing revealed, my particular gun performs best with Core-Lokt.

Core Lokt is a classic hunting round. It’s been made for almost 80 years and is one of the first quality cartridges that was readily available over the counter. It also has the advantage of being the least expensive of the rounds I tested, which shows that spending more doesn’t always produce the best performance. 

There are plenty of other loads I’m curious about and will be testing over time. For now, though, I’ve determined that Core-Lokt, a proven and reliable round, is quite accurate through my rifle…when I do my part…and will work for me.

In short, take the time to test a few different brands and bullet weights from your particular gun(s). Then you’ll know you’re carrying and shooting the stuff that works best for you. The peace of mind that knowledge gives you is priceless. 







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  1. My Sigma(I know, but I got the one that runs right) will use all types of ammo from fmj to bronze hollowpoints. But for best accuracy(I know, I know, Sigma.) It really likes the 124 grain nato standard white box ammo. Most guns have a brand or style of bullet they prefer. It’s up to us to figure out which. And it’s fun.

    And it can be a matter of life or death. I owned a number of medium frame duty size revolvers in .38 special. Then I decided to buy a j frame. What i had always preferred in my larger revolvers was the old FBI load. +P 158 grain LSWHP.

    So that was going to be my carry load in the j frame. Until I tested it at the range. I experienced bullet creep in a spectacular fashion. The gun was immobilized after only 3 shots and required 3 hands to free it up. Could have been a disaster in the real world.

    Test your ammo. It’s fun and it could be life saving.

    • Don’t be so hard on your Sigma! As the saying goes, if it stupid but works – it’s not stupid.

      • At the time I bought the Sigma it was strictly under the ‘you need a 9×19. It’s the most common and popular caliber in the world. You’ll be able to get it no matter what happens or where you’re at’.

        When the big ammo shortage hit which ammo went away first? It was probably a tie between 9×19 and .22 rimfire.

        Eventually 9×18 dried up but I was able to get it for a long while after 9×19. If I had to do it again I’d go with .40 S&W. It was always available.

    • ” Until I tested it at the range. I experienced bullet creep in a spectacular fashion. The gun was immobilized after only 3 shots and required 3 hands to free it up.”

      A few months back in TTAG, there was a .38 P ammo announcement that was …different.

      It looked like a wad-cutter, fully flush with the case mouth, and a heavy roll-crimp on the mouth.

      It appeared impervious to bullet-creep…

      • I shoot these as my defensive load out of my J frame airweight. I’ve never had a problem with jump at all.

  2. I was shooting an IDPA match a couple of weeks ago and my go-to match ammo (for 5 years or so) all of a sudden wouldn’t feed. Turns out the bullets in the batch I was shooting weren’t pressed as far into the casings- they were about 1.5mm proud- and they bound up on the rifling before the gun could go into battery. Everything was still within SAAMI spec, but it didn’t run in my gun, on that day.

    If you remove the barrel from your handgun you can safely drop individual rounds in the chamber and check the fit.

    • I’ve had a similar thing happen. Buddy of mine reloads 9mm and his reloads and ONLY ONE of my 9mm pistols were completely incompatible. Ironically, he had tailored these loads to his CZ75, and it was my CZ75 that we couldn’t use them in.

      Basically a round wouldn’t chamber. We could tap the back of the slide most of the time and fire off one round. The following round would do the same thing. When I gave up and tried to eject a round, it actually pulled the bullet out of the casing, and the bullet remained stuck in my barrel. We had to disassemble the gun, and use a dowel rod to get that bullet out.

      Later on we measured his reloads and they averaged .356 dia. We checked a bunch of different factory ammo and none of it was greater than .355. (All the factory ammo fed and fired fine in my gun.)

      • That is due to the throat in the chamber, also called the “leade”. A bullet needs to transition from a stable, non spinning condition, to an accelerating, spinning condition as it travels up the bore. To ease this transition, there is an area, right in front of the chamber, where the lands of the rifling are machined down to create a ramp of sorts, to ease the bullet into the rifling. This varies not only with firearm design, but between individual firearms of the same make and model. That CZ must have had a shorter leade, so when the round was driven into the chamber, the bullet was simultaneously rammed into the rifling lands. That’s why the bullet stayed in the bore when the case was pulled out.
        Many firearms shoot most accurately in almost this condition, with the bullet just touching the lands, but not rammed so hard into them as to refuse to be extracted. This also causes higher pressure, which accuracy reloaders compensate for by reducing the powders charge, taking slightly less velocity in return for better groups.

  3. I recently found a classic deer rifle (late 70s Rem 700 BDL .30-06) at a can’t-leave-it-at-the-pawnshop price.

    Testing with several weights of otherwise identical factory loads, I was embarrassed by my 3 to 5 moa groups with the 165 gr. I buried those targets and started rehearsing excuses. Maybe somebody sold their rifle because it’s not much of a shooter? Really, I’m not that terrible!

    Then I opened the box of 180 gr and immediately delivered three .75 moa groups. Both the rifle and I are vindicated.

    The problem is, I had told myself I was going to be satisfied using whatever ammo I could get off the shelf at Sportsman’s Warehouse. Now I’ve seen this rifle’s potential, and I’m buying bullets and working up ladder loads, chasing that Goldilocks recipe.

    So the moral of this story is: Don’t test your ammo. That could lead to spending more time and money than you intended.

  4. Its not just rifles either. Because of their highly stressed nature, all firearms are unique. Each one is slightly different than each other one, even though they are made to be as identical as possible. These microscopic differences mean that all firearms will prefer certain ammo/projectiles over others.
    Unfortunately, the only way to find out which your gun prefers is to try them out. OFC, the best would be to try out EVERYTHING, but since that’s not practical, the go to procedure is to shoot a cross section of what you can lay your hands on and see which your particular gun prefers.
    Usually, this will take the form of shooting for accuracy with rifles, and functionality with pistols. Many is the semiauto that will fail with one kind of ammo and yet be 100% reliable with another. Being a short range proposition in the first place, accuracy is much less important for pistols. There are exceptions to this OFC, like handgun hunting, but by and large very few care whether their glock will shoot 2 inch, or 4 inch, groups. Many won’t even bother to measure a distance for defensive handguns. The standard for pistols used to be at 25 yards, but seldom do I see any pistol shooting at those distances these days. I still like the challenge of 50-100 yards with a pistol, but I don’t see very many others doing so…

  5. When I first started carrying concealed I bought some Hornady critical defense in .45. Hornady is a great brand that I’ve shot before and since, and currently use the same rounds on duty. However, I didn’t fire any out of that first box until about a year and a half later. Simply on a whim I tried to fire my hollow points to find that *none* of them fired. The primers were barely dented. I was able to get a few to fire after putting them back in several times. I did some research at the time, and as I recall a whole Lot got recalled; I just didn’t know about it. As a result, I now take two rounds out of every box or case and use them for my range visits, regardless of whether they are plinking rounds, self defense, or whatever. That would be an extremely embarrassing way to die. I wish more people would consider that. There are many security companies and Law Enforcement agencies that have specific duty ammunition, and some of them issue it out. Without adding a requirement to test each box, you could run into a serious incident. Unlikely as it is, it happened to me….

    • I like to run two full mags of rapid fire, just make sure everything goes bang and feeds well in a semi-realistic situation.

  6. Federal SMK in .308 won a competition I had in my Savage 11 and Henry Long ranger. I tried 10 different weights and brands and nothing came close to the 168gr pills in Sierra Match King.
    Of course YMMV.

  7. Testing the ammunition for each firearm, and each intended use for that firearm is a “must”. I have met several people who only shot “range loads” from their pistols (owing to price), but have Factory ammo at home they have never shot. Range Loads can vary from batch to batch and are sometimes a bit lighter than Factory ammo. Having convinced a couple of those folks to bring their Factory ammo to test, I was not surprised when they got back to me and Thanked me for that advice because they experienced various surprises.

    Rifles can be sensitive to bullet weight because barrel twist can affect accuracy. Too light a bullet for the twist rate can cause erratic results downrange. Pistols and revolvers are more forgiving, but in pistols you may need to change recoil springs to accommodate different bullet weights.

    So, Test your Home Use ammunition and be sure it is reliable in your pistol or revolver before your life depends on it. Test your rifle ammunition for accuracy for Hunting (you know why). Settle on a specific brand, bullet weight and design. Retest and replace your on-hand supply from time-to-time.

    • “Too light a bullet for the twist rate can cause erratic results downrange.”???
      Perhaps so, but I’ve never seen evidence suggesting that a projectile can be TOO stable. In any case, the results downrange from a bullet too light for the twist rate are nowhere near the erratic results you will see from a too heavy bullet.
      A bullet needs to spin to achieve stability. Longer and heavier projectiles need to spin faster to be stable. If they aren’t spun sufficiently rapidly they will tumble end over end in flight, losing almost all accuracy.
      On the other hand, I’ve never noted erratic results from over-spinning a bullet, at least not until the bullet disintegrates in flight, which I’ve done numerous times in hot .22 centerfires with bullets in the 35-45 grain range. You can really get those little hornet type pills moving in a swift or .22-250.

      • I experienced widely spread groups at 100 yds from an AR15 A2 HBAR with 55 grain bullets, switched to 62 gr to 68 gr and groups came down significantly tighter. “Erratic” in my book is 8 to 12 inches at 100 yds when you are confident your point of aim is consistent.

        OTOH my M1A shoots the same tight groups at 100 yds with147 gr bullets to 174 gr bullets (provided tha POA is consistent). YMMV.

      • I don’t know if I’d call it “over stabilization” but both accuracy and terminal performance will suffer when any particular round is spun too fast.
        With the same bullet, at the same speed, there is a sweet spot for twist rate. There is always that one particular rate that makes smaller groups than any rate slower, or faster, for a particular round.
        What I find intersting is that there is also a difference in wounding patterns that are the same way. I’ve never quite figured that one out.

        • There is a mathematical formula created by a Brit many years back that calculates the optimal bullet weight for barrel twist. It works, but haven’t been able to find it for years now. Ever heard of it?

        • DerryM, it’s called the Greenhill Formula. A quick web search will find it.

          Manufacturers then take this ideal number and round it down to the next number convenient for manufacturing processes.

          It is better the rifling pitch is a bit faster than is ideal than slower. Wrong barrel pitch can limit performance and cause popularity to fail. Ever heard of .244 Remington?

          • Thanks very much, Southern Cross! I had notes but had not used it for 20+ years and could not recall Greenhills name, nor make sense of my notes. It is really useful.

        • No problem mate. Always glad to help. You can have a chuckle that you were helped by someone from Australia. But this is the nature of the internet bring people together from all over the world.

  8. I have a custom .243 built on a military Mauser action that my dad gave me when I was 14. Always shot handloads through it, nearly all of which were sub MOA. Last year, I bought a couple boxes of factory rounds. Hornady and Federal high end stuff. The Hornady shot 4” groups from the bench. Federal grouped at about 2.5”. I was seriously concerned until it occurred to me that the bullets in the factory loads were seated quite a bit deeper than my handloads, so they were jumping a much larger gap to the lands. Put 3 of my pet loads into a 3/4” group and breathed a sigh of relief. No more factory loads. I wonder if neck only resizing will produce even tighter groups. Hmmm, new fall project.

  9. I recently had to explain a similar concept to a family member who has been shooting for years and enjoys changing up his carry load more often than he changes his underwear. After I talked him into actually shooting his current carry ammo we discovered that the particular load shot way low and wasn’t reliable in his glock. It’s a good thing he didn’t need his weapon before then.

  10. I’ve bought a used rifle that the owner was selling as it was not accurate.
    It was amazing how cleaning barrel properly with copper solvent changed it from 6 moa to 1. Have also seen loose mounts etc blamed for bad ammo.

    That said rifles do like different ammunition. Trying to find the best combination is a fun off season activity. Personally I handload trying different projectiles etc for that sweet spot of half Moa or less.

  11. On one hunting trip I was using ammunition that grouped about 2MOA. My colleagues said I wouldn’t hit anything on the trip. But I had practiced with that rifle in several service rifle competitions before the trip so I knew the impact and the handling under stress.

    Guess who shot the most pigs on the trip with 7 in one engagement?

    The M48A Yugoslav Mauser in 8×57 with a 2.5x scout scope. The load was reworked Turkish 8mm with the 154g FMJ replaced with a 170g RNSP and the powder charge reduced. Velocity measured by the chronograph was about 2720 fps. Everything I hit went down and stayed down when hit by the flying trashcans. And my hit percentage was in the 90+% because of my practice, unlike my colleagues who could barely reach 50% hits.

  12. I know you were demonstrating how different ammo behaved but you could have zeroed the scope on gotten the same accuracy for all three brands.

  13. My M1 Carbine will clover leaf at 100 yards with, and ONLY with, PPU FMJ….My PAP 59/66 shoots moa with Wolf Polyformance spitzer boattail FMJ …nothing else comes close…My 1911 Schmidt-Rubin makes 1 hole groups with either PPU or Swiss mil surp…anything else is a waste of time..Sometimes it takes a while to find the right stuff, but it’s worth it.

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