Tag Archives: propellants

Reloading Components, Reloading Corner

RELOADERS CORNER: Picking Propellants

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There are a whopping lot of propellants on the market. How do you choose one? Well, usually it’s more than one… READ WHY

PROPELLANT

Glen Zediker

All we ever really want is a propellant that provides high consistent velocity, small groups at distance, safe pressures over a wide range of temperatures, and burns cleanly, and, of course, it should meter perfectly. Dang. I know, right?

Ultimately, propellant choice often ends up as a compromise and it may well be that the smallest compromises identify the better propellants. Getting the most good from your choice, in other words, with the fewest liabilities.

There are two tiers of basics defining centerfire rifle propellant formulas. The granule form can be either spherical (round granules) or extruded (cylindrical granules). Next, the composition can be either single- or double-base. All propellants have nitrocellulose as the base; double-base stirs in some nitroglycerol to increase energy.

There’s been a good deal of effort expended and applied over the past several years to reduce the temperature sensitivity of propellant. Coatings come first to mind, and I use nothing but these “treated” propellants.

This attribute is very (very) important! It’s more important the more rounds you fire throughout a year. A competitive shooter’s score hinges on consistent ammunition performance. Test in Mississippi and then go to Ohio and expect there to be some change in zero, but a change in accuracy or a sudden excess of pressure and that’s a long trip back home. It’s common enough for temperatures to (relatively speaking) plummet on at least one day at the National Matches, so my 95-degree load has to function when it’s 50.

extruded propellant

Some are decidedly better than others in this. There are several propellants I’ve tried and will not use because I didn’t get reliable results when conditions changed. Some gave outstanding groups on target, on that day, at that hour, but went goofy the next month when it was +20 degrees. Heat and cold can influence pressure in a sensitive propellant.

Single-base extruded (“stick”) propellants are my first choice. A good example of one of those is Hodgdon 4895. These tend to be flexible in maintaining performance over a wider range of velocities, related to a wider range of charge weights. For instance, I’ll vary the charge weight of the same propellant for ammo for different yard lines. I’m reducing recoil or increasing velocity, depending on what matters more. Zero and velocity are different, but accuracy doesn’t change.

H4895
There are a few single-base extruded propellants that show impressive flexibility in load levels as well as in different round structures. This is one of the most flexible I’ve used, and I use a lot of it!

Spherical or “ball” propellants (these are double-base) are a good choice for high-volume production, and also tend to be a great choice for highest velocities at safe pressures. These meter with liquid precision. They, however, tend to be less flexible. That means they tend to work best at a set and fairly finite charge and don’t do as well at much less or more than that, and especially at much less than that. More in a minute.

spherical propellant
Spherical propellants tend to be volume sensitive. My experience has been they’ll perform best when the fill level is a good 90-percent. That means there’s a little smaller gap between one that’s good with, say, 50gr bullets and one that works well with 60s. It’s likely to be two propellant choices, not just one. Generally, spherical propellants do their best when loaded near-to-max.

Double-base extruded propellants (sometimes called “high-energy”) do, yes, produce higher velocities at equal pressures compared to single-base but also tend to be less flexible and exhibit performance changes along with temperature changes. Vihta-Vuori and Alliant are the best known for their formulations in these. Double-base usually burns at a hotter temperature (not faster or slower, just hotter) and can increase throat erosion rate. Some double-base spherical propellants claim to burn cooler. I’m not certain that this is a huge selling point, either way, for a serious shooter, but, there it is.

VV540
Double-base extruded propellants are mighty fuels, but, they tend GENERALLY to be more temperature sensitive and also burn hotter. Now. That’s not always true (I think NONE one of this is always true). With Viht. you can have a choice of double- or single-base in the same essential burning rate; N140 is single-base, N540 is double.

All propellants are ranked by burning rate. That’s easy. That’s just how quickly the powder will consume itself. All reloading data manuals I’ve seen list propellant data in order from faster to slower. For instance, if you’re looking at .223 Remington data and start off with tables for 40-grain bullets, you’ll see faster propellants to start the list than you will moving over to the suggestions for 75-grain bullets.

It’s tough to find a perfect propellant for a wide range of same-caliber bullet weights. Faster-burning propellants tend to do better with lighter bullets and slower-burning tends to get more from heavier bullets. That’s all about pressure and volume compatibility. Again, I have found that a single-base extruded propellant will work overall better over, say, a 20-plus-grain bullet weight range than a single choice in a spherical propellant.

scale pan with powder
Extruded propellants vary greatly in granule size, and, usually, the smaller the better. More precise metering. This is VV540, strong stuff, meters well. There are a few now that are very (very) small-grained (like Hodgdon Benchmark).

The idea, or at least as I’ll present my take on it, is that we want a fairly full case but not completely full. I don’t like running compressed loads (crunching a bullet down cannot be a good thing), and excessive air space is linked to inconsistent combustion. We ran tests upmteen years ago with M1As and found that out. Many details omitted, but here was the end: Settling the propellant back in the case prior to each shot absolutely reduced shot-to-shot velocity differences (the load was with a 4895, necessary for port pressure limits, and didn’t fully fill the case).

Generally, and that’s a word I’ll use a lot in this (and that’s because I know enough exceptions), spherical propellants have always performed best for me and those I share notes with when they’re running close to a max-level charge. More specifically, not much luck with reduced-level charges.

Too little spherical propellant, and I’m talking about a “light” load, can create quirky pressure issues. Workable loads are fenced into in a narrower range. This all has to do with the fill volume of propellant in the capped cartridge case, and, as suggested, that’s usually better more than less. That further means, also as suggested, there is less likely to be one spherical propellant choice that’s going to cover a wide range of bullet weights. That’s also a good reason there are so many available.

With some spherical propellants, going from a good performing load at, say 25 grains, and dropping to 23 can be too much reduction. One sign that the fill volume is insufficient is seeing a “fireball” at the muzzle. Unsettling to say the least.

Spherical propellants also seem to do their best with a “hot” primer. Imagine how many more individual coated pieces of propellant there are in a 25-grain load of spherical compared to a 25-grain charge of extruded, and it makes sense.

However! I sho don’t let that stop me from using them! I load a whopping lot of spherical for our daily range days. We’re not running a light load and we’re not running heavy bullet. We are, for what it’s worth, running H335.

So, still, how do you choose a propellant? Where do you start? I really wish I had a better answer than to only tell you what I use, or what I won’t use. There are a lot of good industry sources and one I’ve had experience with, including a recent phone session helping me sort out Benchmark, is Hodgdon. You can call and talk with someone, not just input data. Recommended.

When it’s time, though, to “get serious” and pack up for a tournament, I’m going to be packing a box full of rounds made with a single-base extruded propellant that meters well. As mentioned before in these pages, I have no choice in that, really. I’ll only run the same bullet jackets and same propellant through the same barrel on the same day. I need a propellant that works for anything between 70- and 90-grain bullets.

With time comes experience, and I know I sure tend to fall back on recollections of good experiences. I admittedly am not an eager tester of new (to me) propellants. I have some I fall back on, and those tend to be the first I try with a new combination. There are always going to be new propellants. That’s not a static industry. I may seem very much stuck in the past, but I no longer try every new propellant out there. I like to have some background with a propellant, meaning I’ve seen its results in different rifles and component combinations. Mostly, I ask one of those folks who tries every new propellant…

There is a lot of information on the internet. You’re on the internet now. However! There’s also not much if anything in the way of warranty. If you see the same propellant mentioned for the same application a lot of times, take that as a sign it might work well for you. Do not, however, short cut the very important step of working up toward a final charge. Take any loads you see and drop them a good half-grain, and make sure the other components you’re using are a close match for those in the published data.

One last: Speaking of temperature sensitivity: Watch out out there folks. It is easily possible for a round to detonate in a rifle chamber if it’s left long enough. Yes, it has to be really hot, but don’t take a risk. A rash of rapid-fire can create enough heat. Make sure you unload your rifle! Here’s an article you might find interesting.

CHECK OUT CHOICES AT MIDSOUTH
Hodgdon
Shooters World
Vihtavuori
Alliant

The preceding is a specially-adapted excerpt from Glen’s book Top-Grade Ammo. Available HERE at Midsouth Shooters Supply. Visit ZedikerPublishing.com for more information on the book itself, and also free article downloads.

 

Ammunition, Reloading, Reloading Corner, Rifles

RELOADERS CORNER: 3 Helps For Easy Load Work-Ups

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Read this before you start the process of working up a load for your new rifle! It could save you huge amounts of time and money… Find out more!

Glen Zediker

Spring is around the corner. Well, if you walk way out into the street and squint really hard you can at least think you see it… Well it’s coming soon enough, at least, now’s a good time to get ready.

I never have been big on the personal value of published load data. The data I’m referring to is that from propellant and other component manufacturers, and also from articles done by independents. I think all such information, at most, provides a place to start, and it also gives some ideas on tendencies and cautions, and provides means for comparisons. But. I don’t think it can be taken straight to the loading bench with any guarantee of success, or of attaining “advertised” performance. And I say that not because I don’t think these folks don’t know what they’re doing. They do! It’s because, after way more than enough experience in proving myself right, I can tell you absolutely that their rifle is not your rifle! Neither, necessarily, are their propellant, primer, case, or bullet. Always take careful note of the barrel and components used for any published test data, and compare them to yours. In later comparisons of my notes with published data, sometimes I’m higher, often times I’m lower, and enough times I’m way lower… That’s the main concern there.

It’s not at all difficult to learn to develop your own loads, to essentially write your own loading manual.

To do this efficiently, you need to learn to load at the range. Right, right there near to where you’re testing. An unremarkable investment in a few tools and a little creativity can provide a way to take your show on the road.

Lee press mounted outdoors
You don’t have to invest a fortune to take your show on the road. A C-clamp and one of these little Lee Reloader presses is all you need! And a good powder meter. One with a clamp is handiest, or just mount it to a piece of wood and clamp that down (even a pickup tailgate works just fine). One clamp is adequate on the press since bullet seating is all in the “down” direction and not much force is needed.

The reason to do this is because it provides a way to precisely chart results. It’s a more reliable and accurate way to proceed. Otherwise, the option is to load varying charges at home and then see what happens at the range. That’s okay, but not nearly as good as on-the-spot experiements. Plus, you won’t have left over partial boxes of poor-performing rounds. It’s more economical and way on more efficient.

The preparation part, and this is what you might spend the remaining cold month or two working on, is, first, to get the tooling ready and, second, and most important, to start making notes on your powder meter.

Important: To be able to work up at the range, it’s mandatory that you’re using a meter that has incremental adjustment. Either a “click”-type “Culver”-style insert or, at minimum, a micrometer-style metering arm. You’ll be relying on the meter, not scales, to progress upward in propellant charges, and you absolutely have to know what the values are for each increment using the different propellants you plan to test. That is where you’ll be spending time prior to doing your homework. It’s well worth it! It can be a nightmare trying to get scales to read accurately outdoors, including the digital type.

Harrells meter mounted outdoors
I map out the incremental values of each click on my Harrell’s meter adjustment drum with the propellant I’ll be testing, and it’s really easy to step up each trial with confidence. I carry the whole kit in a large tool box.
Harrells meter close up
This is a Culver insert. It’s a huge help in following this process. It’s precise and repeatable.

Equipment List and Set-Up
When I need to do load work, I size, prep, and prime new cases and put them in a cartridge carrier (usually a 100-round box). I then pack up my little press, seating die, my meter, some cleaning gear, C-clamps, and my propellants. The press and meter and cleaning gear go in a tool box. I usually carry the propellants in a picnic-type cooler. And, very importantly, my chronograph. A notebook, some masking tape, and a sack lunch… I might be there a while.

Always (always) use new cases for load work-up.

When I get to the range, I’ll clamp-mount my press and meter to a bench, get out all the rest, and set up the chronograph. Take a target downrange and tack it up. I test at 300 yards, unless the load is intended for shorter-range use. I initially test longer-range loads at 300. Maybe I’m lazy, but longer-range testing is a tad amount more tedious. I’ll come back for that after I have a contender or two.

Working Up The Load:
The reason it’s a “work-up” is clear enough: we’re almost always looking to get the highest velocity we can, safely. High velocity, or higher velocity, is usually all-good. Shorter flight time means less bullet drift and drop, and a harder hit.

So working up means increasing propellant charge until we’re happy: happy with the speed and also that the cases will still hold water. (And more about that next time…)

blown primer
Keep track of the cases in the order they were fired. This helps later on when the effects can be measured. This little outing here, though, didn’t require a gage to cipher: a tad amount hot on that last little go around (last case bottom row on the right). Thing is, I didn’t load a whole boxfull of those chamber bombs to take with me, and that’s the beauty of loading right at the range.

Very important: it is vitally necessary to have established a goal, a stopping point, prior to testing. That is one of the functions of published data. That goal is bound to be velocity, not charge weight. And that, right there, is why you’re working up at the range: you want to get “advertised” velocity and need to find the charge weight that produces it.

I work up 0.20 grains at a time. Sometimes it’s more if I’m reading an unuseably low velocity on the initial trial. Since my meter has a “Culver”-style insert, which I trust completely, I reference its number of clicks in my notes rather than the grain-weights (a Culver works like a sight knob, and reads in the number of clicks, not the weight itself). I check the weights when I get back, and I do that by clicking to the settings I found delivered, and then weighing the resultant charges. Otherwise, just throw a charge into a case and cap it with masking tape (clearly labeled).

It’s not necessary to fire many rounds per increment. “Mathematically” 3-5 rounds is a stable enough base to reckon the performance of one step. Of course, I’ll be shooting more successive proofs-per-trial once I get it close. Some folks, and especially competitive shooters, wear out a barrel testing loads. That’s not necessary.

Here are 3 things I’ve found over the years to better ensure reliable results. Learned, of course, the hard way.

1. Limit testing to no more than one variable. I test one propellant at a time, per trip. If you want to test more than one on one day, bring the bore cleaning kit and use it between propellant changes. Results are corrupt if you’re “mixing” residues. Same goes for bullets. Otherwise, though, don’t clean the barrel during the test. I fire my most important rounds after 60+ rounds have gone through it, so I want a realistic evaluation of accuracy and velocity.

2. Replace the cases back into the container in the order they were fired. This allows for accurate post-test measurements. Use masking tape and staggered rows to label and identify the steps. I use 100-round ammo boxes because they leave enough space for the tape strips.

3. Go up 0.20 grains but come off 0.50 grains! If a load EVER shows a pressure sign, even just one round, come off 0.50 grains, not 0.10 or 0.20. Believe me on this one…

Check out chronographs HERE
Take a look at suitable meters HERE

The information in this article is from Glen’s newest book, Top-Grade Ammo, available HERE at Midsouth. Also check HERE for more information about this and other publications from Zediker Publishing.

Reloading Corner

Improving Tool Alignment: 5 Ways To “Float”

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“If it’s not perfectly aligned, then it should float…” Here’s a few tips on improving concentricity in the handloading process.

Glen Zediker

Water seeks its own level. Moving parts seek their own centers. Trick is getting the centers to agree. When centers coincide, that’s “concentricity,” and that a prime goal in the process of creating better ammunition. Anything under pressure and moveable, such as a cartridge case being sized or a bullet being seated into a case neck, moves toward a path of least resistance. If all the tooling associated is straight, and the case hisseff is uniform, then the result is “straight.” However! That’s in a perfect world.

In reality, which is accepting existence of tolerances and misalignments, taking steps to help two conflicting centers come close together comes from providing some free-play in the apparatus. I call it “floating.” And it works, and here are a few ways to use it.

Now, free-floating can work two ways. One is to incorporate a float into the mechanism in use, and another is to create float, and then use that to center a piece prior to snugging it down.

1. Shellholder
This first one might seem a tad amount clumsy, but it’s really easy to get used to in operation. Presses with conventional shellholder arrangements use a spring clip to retain the shellholder in its slot atop the press ram. Get this clip gone! It cocks the shellholder askew.

The solution is to incorporate an o-ring to retain the shellholder in its slot. Get one at any real hardware store. Size that works is usually 7/8-inch outside diameter, 11/16 inside diameter, 3/32 thickness. The o-ring fits into the exterior channel previously occupied by the spring clip. To install a shellholder you just roll the ring down a tad, slide in the holder, and let the ring back up to block its exit out the front.

This modification lets the shellholder sit flat, as it should, and also provides some wiggle room so the case can align itself with the die opening. [Photo from Top-Grade Ammo]
This modification lets the shellholder sit flat, as it should, and also provides some wiggle room so the case can align itself with the die opening. [Photo from Top-Grade Ammo]
2. Sizing die lock ring
Speaking of wiggle room, there’s a whopping lot of it in a 7/8-14 thread set. That’s pretty coarse. Taking up the play created by thread-to-thread gaps goes a good ways toward “straight” installation of a die into a press. There are a couple of ways to help this.

One is to always (always) tighten a die locking collar ring when there is a case inside the die, and the ram is fully extended upward (handle all the way down). This bit of pressure helps to bring the die into straight alignment. Problem is that it also makes the daggone die hard to remove. Just get stern with it. After initial removal, subsequent re-fittings are easy. I use a “strap wrench” (plumbing supply and real auto parts stores have one for you) if it’s stubborn to turn loose after being tightened initally. Pliers result in cosmetic, but not real, damage. Lock rings with wrench-flats are dandy.

Always put an index mark from die lock ring to die body to press top. That’s a simple way to verify return to “zero” when a die is installed back into your press. And ALWAYS install and remove the die holding ONLY the locking ring! Never-ever the die body. Any teeny body rotation within the locking ring, which is easily undetectable, requires repeating the process of die adjustment.
Always put an index mark from die lock ring to die body to press top. That’s a simple way to verify return to “zero” when a die is installed back into your press. And ALWAYS install and remove the die holding ONLY the locking ring! Never-ever the die body. Any teeny body rotation within the locking ring, which is easily undetectable, requires repeating the process of die adjustment.
I prefer clamping lock rings, like these from Forster. Those with a set screw can cock when the screw tightens in against the angled threads.
I prefer clamping lock rings, like these from Forster. Those with a set screw can cock when the screw tightens in against the angled threads.

For these tricks, choose a case that represents your best: get one with the most consistent neck wall thickness.

3. Expander/decapping assembly
There’s some “feel” involved in this one, but it is worthwhile. To get the expander in your sizing die sitting on center, run up a case fully and then slowly withdraw it until you feel the expander lodge inside the case neck. Then put a little pressure down on the handle, in the direction of raising the ram, while you tighten the locking apparatus.

When it’s possible, and it almost always is, secure the pieces-parts when they’re doing their jobs. For instance, tightening the locking rings on a decapping stem when the expander is holding inside the case neck helps bring the stem into straight alignment, and the expander along with it.
When it’s possible, and it almost always is, secure the pieces-parts when they’re doing their jobs. For instance, tightening the locking rings on a decapping stem when the expander is holding inside the case neck helps bring the stem into straight alignment, and the expander along with it.

4. Lock-ring o-rings
Here’s one I suggest but don’t usually follow… Lemmesplain: It works but I prefer these other means because they’re more “secure.” However! Installing an o-ring up under the die body locking ring (sizers and seaters) provides a cushioned flexibility that provides for takeup in the amount and “direction” needed when a case is run up into a die. O-ring size is 7/8-inch inside diameter and a thickness of 1/8-inch.

O-ring trick: the flexible ring allows for some “wiggle room” to help case and die centers match. Trick is reinstalling the die to hold the desired setting, and the index mark really helps. Hold only the lock ring when threading the die in and out!!
O-ring trick: the flexible ring allows for some “wiggle room” to help case and die centers match. Trick is reinstalling the die to hold the desired setting, and the index mark really helps. Hold only the lock ring when threading the die in and out!!

5. Bullet seating die stem
This one is pretty simple: tighten the lock on the stem when there’s a seated bullet run up into the die. Threads are finer on stems than on die bodies, but better is a better. This is for a conventional-style seating arrangement. Those that use a spring-loaded sleeve arrangement, like a Redding Competition Seater, are good to go as are.

The preceding is a specially-adapted excerpt from the book Top-Grade Ammo just released by Zediker Publishing.

Reloading Corner

Load Testing Insight: 5 “Rules” for Load Work-Up

10 Comments

Don’t waste time and money collecting half-boxes of “loser loads.” Here’s how to start and finish load work-up in one day.

Glen Zediker

Last time I talked a little about keeping your ammo pressure-safe, under a range of conditions. Quite a bit of that dealt with observations made during load work-up. So this time I’d like to talk more about the work-up process I use.

The reason for the term “work-up a load” is pretty clear: we’re almost always looking to get the highest velocity we can, safely. High velocity, or, more clear, higher velocity, is usually all good. Shorter time of bullet flight to the target means less drop and drift, and a harder impact.

So working up means increasing propellant charge incrementally until we’re happy. Happy with the velocity or happy that the cases are still able to hold water. Ha. As said last time, it’s vitally and critically important to have a stopping place, a goal to be reached, prior to testing.

I also mentioned an “incremental” load work-up method that I have followed for many years, and it’s served me very well. I do all my testing and work-ups at the range. I load right then and there. I take boxes of sized and primed cases, and my Harrell’s powder meter, and a small press that I c-clamp to a bench. The press, of course contains my seating die. And the most important pieces of gear are a notebook and a chronograph.

load at the range
You don’t have to invest a fortune to take your handloading show on the road. Some c-clamps and one of these little Lee Reloader presses is all you need! And a good powder meter. One with a clamp is handiest, or just mount it to a piece of wood and clamp that down (even a pickup tailgate works just fine).

Before the trip, I have taken the preparation time, done the homework, to know exactly how much “one click” is worth on my meter. It varies with the propellant, but by weighing several examples of each click-stop variation (done over at least 4 stops) I can accurately increase the charge for each test a known amount.

reloading at the range
I map out the incremental values of each click on my Harrell’s meter adjustment drum with the propellant I’ll be testing, and it’s really easy to step up each trial with confidence. I carry the whole kit in a large tackle-type box.

I work up 0.20 grains at a time. Sometimes it’s more if I’m reading a low velocity initially. Since I have a meter with a “Culver” insert, which I trust completely, I actually reference the number of clicks in my notes rather than the weights. I check after the weights when I get back home, and I do that by counting to the setting and weighing the charge. It’s easy enough also to throw a charge into a case and seal it over with masking tape.

I started loading at the range because I got tired of bringing home partial batches of loser loads. And, you guessed it, the partial boxes usually contained recipes that were too hot. The only way to salvage those is to pull the bullets. Tedious. Or they were too low, of course, and fit only for busting up dirt clods. Plus, I’m able to test different charges in the same conditions. It’s a small investment that’s a huge time-saver.

During my work-up, I fire 3 rounds per increment. As it gets closer to done, I increase that to 5. Final testing is done with 1 20-round group. Does 3-round volleys seem inadequate? It’s not if there’s confidence that the rounds are being well-directed and speed is being monitored. If I’m seeing more than 10-12 fps velocity spreads over 3 rounds, I’m not going to continue with that propellant.

Here are a few things I’ve found over the years to better ensure reliable results. Learned, of course, the hard way.

  1. Limit testing to no more than one variable. I test one propellant at a time, per trip. If you want to test more than one on one day, bring the bore cleaning kit and use it between propellant changes. Results are corrupt if you’re “mixing” residues. Same goes for bullets. Otherwise, though, don’t clean the barrel during the test. Don’t know about you, but I fire my most important rounds after 60+ rounds have gone through it, so I want a realistic evaluation of accuracy (and zero).
  1. Replace the cases back into the container in the order they were fired. This allows for accurate post-testing measurements. Use masking tape and staggered rows to identify the steps. I use 100-round ammo boxes because they have enough room to delineate the progress.

    ammo pressure
    Keep track of the cases in the order they were fired. This helps later on back in the shop when the effects can be measured. This little outing here, though, didn’t require a gage to cipher: a tad amount hot on that last little go around (last case bottom row on the right). Thing is, I didn’t load a whole boxful of those chamber bombs to take with me, and that’s the beauty of loading right at the range.
  1. Use the same target for the entire session. (Put pasters over the previous holes if you want, but don’t change paper.) This helps determine vertical consistency as you work up (when you’ve found a propellant that shows consistency over a 3-4 increment range, that’s better than good).
  1. Exploit potentials. If you take the lead to assemble a “portable” loading kit, the possibilities for other tests are wide open. Try some seating depth experiments, for instance. Such requires the use of a “micrometer” style die that has indexable and incremental settings.
  1. Go up 0.20 grains but come off 0.50 grains! Said last time but important enough to say again here. If a load EVER shows a pressure sign, even just one round, come off 0.50 grains, not 0.10 or 0.20. Believe me on this one…

Last: Keep the propellant out of the sun! I transport it in a cooler.

shooting chrony
Chronograph each round you fire. It doesn’t have to cost a fortune to get an accurate chronograph. This one is inexpensive and, my tests shooting over it and my very expensive “other” brand chronograph (literally one cradled in the other) showed zero difference in accuracy. The more expensive chronographs mostly offer more functions. The muzzle-mounted chronos are fine and dandy too.

The preceding was a specially adapted excerpt from the new book, Top-Grade Ammo by Glen Zediker. Check it out at ZedikerPublishing.com or BuyZedikerBooks.com