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Apr
20

The Zero 121gr JHP

I’ve been periodically posting a short review of the gear I’ve been using. While success as a practical shooter is primarily about a given shooter’s abilities, having solid gear goes a long way to allowing the shooter to make the most of their talent. To that end, the accuracy potential of your ammunition is certainly important, and the bullet has a pretty large impact on that potential. As I write this, my current bullet is a Zero 121gr JHP.

For best accuracy, consistency of all important dimensions is key – length, dimension, weight. I’ve found Zero bullets to hold pretty good tolerances on all counts. I’ve shot their 121s and their 125s Both are nominally a .356″ diameter bullet, but tend to mic out consistently at .3555″ for me. That diameter controls how tightly the bullet seals into the bore, and thus is very important for how the load develops pressure. A slightly larger bullet requires more force to shove into the throat of the chamber, and thus causes a higher peak pressure, given the same load otherwise. The barrel in your gun may “like” (ie, group best with) a bullet that’s slightly larger or smaller than the barrel’s nominal diameter. Most guns chambered for a .38 Super or 9mm variant are nominally .355″ bore (that’s usually groove to groove in the rifling). The thing is, if the bullet diameter isn’t consistent, you’ll get inconsistent pressure from your loads, and that will definitely affect accuracy. If the variance is large enough, or the bullet is consistently too small for your bore, the bullet won’t seal up correctly, and you’ll have really poor accuracy. Run a bullet that’s too large (for instance, a .358″ bullet for a .357 Magnum), and you may also have accuracy problems.

The length of the bullet must also be consistent – but it may be counter intuitive where to measure length. The important length is the one your seating die will use to seat the bullet. This insures that your ammo will always have the same starting point for combustion. The bullet also needs to be consistent in length where it meets the rifling of the barrel. This insures pressure builds the same way every time, too. Unfortunately, I don’t have a good way to measure the 2nd one, at the moment. These bullets run a very consistent .555″, with an occasional .556″. Very nice.

Finally, weight. Most bullet tend to run a little bit lighter than their nominally declared weight. For instance, Zero 125gr JHPs always seem to weigh more like 124.7gr. A grain, by the way, is 1/7000th of a pound. These 121s go the other way, though, weighing between 121.7 and 121.8 grains. That’s superb.

I’ve shot a number of other bullets over the past few years. The Hornady HAP 125gr was more consistent, but overall the Zero does a great job of holding all the appropriate tolerances. As a bonus, the Zero bullet costs about 40% less than the HAP!

Folks have asked me, why a Jacked Hollow Point (JHP)? In an Open gun, you really want to have a bullet that won’t leave lead behind in your compensator. The copper jacket on a JHP completely covers the base, preventing lead from melting off the back of the bullet and depositing in the comp. Full Metal Jacket (FMJ) bullets generally have an exposed lead base, and of course non-jacketed lead bullets have lead exposed everywhere. Coated bullets generally behave like lead bullets at Open gun velocities (1400 fps for these 121s). Some companies make a CMJ – Complete Metal Jacket – design. These are FMJs with an added copper base, so the lead is completely contained within jacketing material. Those work OK, too. However, JHPs reportedly are more accurate than FMJs or CMJs. I don’t know why this is, but my testing over the years seems to bear this out. So, in summary, I use a JHP for cleanliness and accuracy.

The only thing to look at after that is how does the thing group? I think these pictures tell the rest of the story accurately… That’s 5 at 50 yards, and 3 at 25… More than acceptable…

About the author

DaveRe

USPSA Grand Master, NRA Instructor, http://re-gun.com/about/

Permanent link to this article: http://re-gun.com/2011/04/the-zero-121gr-jhp/

3 pings

  1. DR Performance says:

    My current rock: http://bit.ly/edXCLq

  2. xre says:

    RT @drperformance: My current rock: http://bit.ly/edXCLq

  3. Montana Gold Bullet’s 121gr IFP | Re-Gun says:

    [...] I recently picked up a couple of cases of Montana Gold Bullet’s 121gr IFP bullet, because the Zero 121gr JHP isn’t easily findable, right [...]

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