Spirit of '76
Shooting FAQs, Info, ...

Headspace Twist Rate Moly Treatment Barrel Break-In Advice for New Handloaders
Removing Stuck Bullets Shooting Software What is MOA? Bullet Energy Measuring Recoil
Best Brass? Barrel Length & Velocity Temperature & Velocity Maximum Range Working up a Load
Ballistic Coefficient Sectional Density What's the Best Powder? Ammunition and Fires Measuring Group Size
Can somebody give me a good definition and an example of headspace?


Think of headspace as the space between the bolt face or breechblock and the base (head) of the cartridge when the breech is closed. In rimmed cartridges (like the .30-30), it's measured from the bottom of the recess for the rim in the face of the breech and the face of the breechblock or bolt -- in other words, headspace is just slightly more than the thickness of the cartridge rim.

In rimless cartridges (like the .30-06), it's measured from a point on the shoulder of the chamber to the face of the breechblock or bolt. Such cartridges are said to "headspace on the shoulder."

If you don't have enough headspace, you can't close the breech. If you have too much headspace, the bottom (head) of the cartridge can be too far away from the breech, or can be driven forward by the firing pin blow.

As the powder burns and pressure rises, the sides of the case "stick" to the walls of the chamber, but the unsupported base (head) of the cartridge can move back -- and can be literally separated from the rest of the case. The result is a blast of gas that can ruin your rifle and injure you and bystanders.
What is Twist Rate? How can I determine the twist rate of one of my barrels?


Twist rate is length down the barrel of a firearm that it takes for the rifling makes ONE complete turn.

To measure it, put a patch on a tight-fitting jag. Push the jag into the barrel until you feel it grab the rifling. Mark the top of the rod at the breach, and at the back of the rod. Push the rod until the mark on the back of the rod is facing up again. Mark the rod at the breach again. Measure the distance between the two 'foreward' marks - your twist rate will be 1:'your measurement' (e.g. 1:10" - 1 turn in 10 inches).
How does one go about moly treating bullets and barrels?


See my Spirit of '76 Shooting (and Reloading) Pages ... do a 'page search' for "moly". There is also information here regarding the cleaning of moly treated bores.
What's the proper way to break in a barrel?


See my Spirit of '76 Shooting Page ... 'precision shooting' ... do a 'page search' on "break in".

I'm new to reloading. What should I do / buy?


First, you should ask yourself, "Do I really like handloading?" While I can't imagine why anyone would not answer with an emphatic "YES", handloading, like anything else, is not necessarily for everyone. Patience, attention to detail, and a cautious nature are all very important attributes of a good, safe reloader.

If you have never reloaded ammunition, I suggest that you find a mentor who you trust. This should be somebody with good judgement who consistently errs on the side of caution. Learn all you can by actually reloading with your mentor. In addition to learning from your mentor, buy 2 or 3 good reloading manuals. All good manuals (e.g. Speer, Hornady, Sierra, Hodgdon, Barnes, Lyman, Lee, ....) have sections on how to reload and a description (or chapters) of the components (bullets, primers, powders, ...). Read each of these sections at least once. Are you still sure you'd like to reload? GREAT !! Welcome to a wonderful and fascinating hobby.

At this point, if you're on a limited budget, my advice is to buy either the Lee or RCBS kit. These kits come with everything necessary to start handloading ammunition - all the basic tools. However, they do not contain everything you will WANT as a handloader. The kits come with a press, dies, a manual (usually), scale, powder throw, lube pad, etc. What they don't contain are a tumbler (for cleaning cases), case/media separator, specialty dies (neck sizer, micrometer seating die), electronic scale, specialty tools (primer pocket uniformer, flash hole deburring tool, case trimming tools, bullet puller, calipers, ...). These you will gradually accumulate over time (months or years) as you see fit.

If you're not necessarily on a budget, and you're sure you want to keep handloading, then you would probably be better served buying either a high-end kit (RCBS) or 'picking and choosing' equipment from RCBS, Dillon, Lyman, Redding, etc...

Click HERE for more information on getting started.
I have a bullet stuck in my bore, now what do I do?


Here is a safe method that won't damage your barrel. First pour a small amount of penetration oil in the bore, let it settle a few minutes, and then pour a few inches of light machine oil in the bore. Place a rag in the action, point the opening of the action AWAY FROM YOU or anything you care about (I suggest that you do this OUTSIDE). Next, lower a snug-fitting wooden dowel or aluminum rod down the bore (you might consider fitting it with o-rings) and whack it with a hammer. The hydraulic force will thus be evenly distributed and push the bullet out without upsetting it in the bore (cocking it) and really getting it stuck. This will also work with a live round stuck in the chamber - spray in 'WD-40' (to "neutralize" the primer first) and let it sit a day or two. Just FYI - there is some controversey as the whether WD-40 really does neutralize primers.
What ballistics software is available?


See 'software for shooters' on my Spirit of '76 Shooting Page. There are many programs around - freeware, shareware, and those you must purchase.
Most of us know a minute of angle (MOA) is 1" at 100 yards, but does anyone know why it is called a 'minute'? And at 100 yards, why does one MOA equal 1"?

One minute of a degree (1/60 of a degree) subtends approximately one inch at one hundred yards. 1 degree subtends approximately 0.017 inch in one inch. Figuring 60 minutes in one degree, one can calculate how that transforms to 100 yds.

It's all trigonometry. Angles are measured in degrees, minutes, and seconds just like a clock. To figure out MOA you'll need a calculator with the sin, cos, and tan function keys. Here's the equation Tan X .016666 X 3600" = 1.047193392". What does each of these numbers mean: Tan = tangent which is a trig function. .016666 = 1 degree / 60 to give you minutes, and 3600" = 100yds X 36"/yd.

Bottom line 1 MOA = 1.0472" @ 100 yds or 10.472" @ 1000yds. Because that extra .0472" doesn't normally mean much at short range it is usually left off and the 1" approximation is used.

Here's an alternate (and simpler) explanation, from Donna's Technical Ballistics, in case mine is not clear. [Here's a link to Donna's Home Page]
What is Bullet Energy vs. Momentum vs. Taylor Factor ?


Bullet Energy is equal to kinetic energy (KE), which = 1/2 * mass * velocity2.
To calculate the KE of a bullet, use the following formula:
KE = (1/2 * (mass in grains / 7000) * velocity2)/32.185

Bullet Momentum is just = (bullet mass (grains) / 7000)* bullet velocity

The Taylor 'knockdown' Factor = (bullet mass (grains) / 7000) * bullet velocity * bullet diameter (inches)

The Taylor Factor was developed by a famous African Hunter to try to explain why larger diameter bullets were more effective on game than smaller diameter bullets, even when kinetic energies or momentum calculations for both loads were essentially equal.

Now that you know how it is done, download my Recoil Calculator or go to my On-Line Recoil / Shooting Calculator and save yourself the work.
How do I figure Recoil ?


Recoil is determined by a number of factors: bullet mass, powder mass, bullet & charge velocity, and the mass of the firearm firing the charge.

Recoil is calculated as follows:

Recoil Impulse (lb-sec)= (bullet weight * bullet velocity + charge weight * charge velocity) / 225400.0;
Recoil (Gun) Velocity (fps) = 32.185 * impulse / gun weight;
Recoil Energy (ft-lbs) = gun weight * gun velocity2 / 64.37;

velocities are in feet/second
gun weight is in pounds
bullet and charge weights are in grains
a charge velocity of about 4000 to 4700 fps is usually used for smokeless powders, 2000 fps for black powder

Again, now that you know how it is done, download my Recoil Calculator or go to my On-Line Recoil / Shooting Calculator and save yourself the work.
What's the best brass ?


Here are my preferences, in order, for American-made commercial rifle and handgun brass : Winchester, Federal, Remington. Additionally, Starline makes very good handgun brass. I've found the Winchester and Federal brass to be the most consistent for accuracy, Winchester being the slightly better of the two. I haven't used enough of each kind to determine which is the more durable.

I also like military brass, as I have had great success with Lake City (LC), and Frankford Arsenal (FA) - especially the MATCH brass - in my rifles. However, this brass is only made for certain military cartridges. Some foreign manufacturers also make very good brass. IMI also makes very good match and non-match brass, and Norma and Lapua make absolutely PREMIUM quality (and expensive) brass.

Two things that you need to be very aware of regarding military rifle brass is a possible crimp in the primer pocket (also true of handgun brass), and the fact that the brass is THICKER than commercial brass. This means that they will have LESS VOLUME, and therefore will generate HIGHER PRESSURES than the commercial brass given the same powder charge. ALWAYS REDUCE your powder charge when working with military brass.
How much velocity do I lose by having a shorter rifle barrel than the one listed in the reloading manual? ... or ... How much does velocity change as a function of barrel length?


Generally speaking, 25 - 30 ft/sec per inch is a good 'rule of thumb' for high velocity rifle barrels. However, remember that each rifle is a 'rule unto itself', and these comparisons are really only valid when shortening an existing rifle's barrel. The best determination of velocity is by direct measurement. You'll get the best answer by buying (you can chip in with a buddy or two) or borrowing a chronograph, and running your loads through. These days, they are very affordable.

Here's a table from one of the firearms magazines for two rifles, a .30-06 and a 6.5x55mm. Each rifle barrel had 2 inches cut off between tests, and the crown was smoothed.

Barrel Length,
inches		.30-06 Velocities6.5x55mm Velocities
Load ALoad BLoad CLoad DLoad E Load 1Load 2Load 3Load 4Load 5
28n/a n/a n/a n/a n/a 32683189246425432687
263018282824392339310732353137245525282632
243019283724232308311531933137247424812588
222943271823902255303831423038241024602525
202906265323542202295631042955235723842488
182824257923072146292230302890235923552451
162781245822512071281029462790227822532327
avg fps loss / inch 23.737.018.826.829.726.833.315.524.230.0
avg fps loss / inch
27.2     TOTAL
25.95     TOTAL
Legend
.30-066.5x55mm
Load A : 125 gr Nosler BT, 48 gr H322, Win case, Fed 210M Load 2 : 85 gr Sierra HP, 43 gr IMR3031, Norma case, Fed 210M
Load B : 125 gr Nosler BT, 62 gr H4831, Win case, Fed 210M Load 2 : 85 gr Sierra HP, 52 gr Reloder 19, Norma case, Fed 210M
Load C : 200 gr Sierra GameKing, 44 gr IMR3031, Win case, Fed 210M Load 3 : 140 gr Sierra GameKing, 36 gr IMR3031, Norma case, Fed 210M
Load D : 200 gr Sierra GameKing, 63 gr H870, Win case, Fed 210M Load 4 : 140 gr Sierra GameKing, 46 gr Reloder 22, Norma case, Fed 210M
Load E : Hornady Light Magnum, 150 gr Interlock bullet Load 5 : Hornady Light Magnum, 129 gr Interlock bullet

Apparently, one can minimize velocity loss by using a slightly faster powder with a shorter barrel. Of course, changes (for better or worse) in accuracy should also be considered if you decide to change powders. It is also interesting to note that in some cases of barrels between 26" and 22" in length, velocities either stayed the same or actually increased as the barrels were shortened. It looks like the manufacturers got it right when they decided on 22" (std) - 24" (magnums) barrels.

How is the velocity of my rifle ammo affected by temperature?


Obviously, there are no 'cut and dry' answers to this question - but general "rules of thumb" do apply, to my knowledge, for rifle cartridges. There is a direct relationship between temperature and velocity. This means that when temperature rises, so does velocity, and when it drops, velocity also drops. You can generally figure that your velocity will change 2 fps/degree F for 'moderate velocity' (~2700 fps) loads, and 3 fps/degree F for 'high intensity / velocity' (~3800+ fps) loads.

Experiments done at Frankford Arsenal and the Burnside lab back in the '1940s with the 30'06 yielded an average of 1.75 fps per deg F (70-140 deg range); 1.83 fps per deg (15-105 deg range); and 1.55 fps per deg (70- -50 deg range). These are approximations, as there are other variables involved. The Ordnance Department used 1.66 fps per deg F.

At what angle will a bullet fired from my firearm achieve maximum range? Is there a way to figure out maximum range for various cartridges?

Theoretically, any projectile (including a thrown ball, etc...) will achieve maximum range if released at a 45 degree angle. However, that is for a projectile in a vacuum. When you consider the effects that air resistance has on the flight of a bullet, maximum range is achieved when the projectile is released at an angle varying from about 27 degrees to 35 degrees, with the nominal value of 31 degrees often yielding just about the maximum range.

For firearms, very high efficiency is realized at the lower angles. About 65% of maximum range can be obtained by an elevation of just 5 degrees, with about 85% of maximum range realized by an elevation of just 8 degrees !

Unfortunately, I am not aware of a formula for calculating the maximum range of a given projectile in the atmosphere. Probably the best sources for this information are the ammunition manufacturers themselves. Most rimfire ammunition is in the 1.5 mile range, while centerfire ammunition may be capable of travelling 3 to 5 miles.

 When reloading, how do I work up a load for my handgun or rifle?


Click here.

What is "ballistic coefficient"?


Ballistic coefficient is the measurement of a projectile's ability to overcome the resistance of the atmosphere. The higher the ballistic coefficient (BC), the more "slippery" the bullet is going through the air. This means that the bullet is able to move through the air with less air resistance (also known as DRAG). This results in a higher retained velocity and energy downrange and a quicker flight time reaching the target. Since it is getting to the target in less time, there is also less time for the wind to move the bullet off of it's intended path.

Obviously a pointed spitzer boattail style bullet will cut through the air better than a round nose or flat point bullet. This is generally not very noticeable at shorter ranges (under 150 or 200 yards), but long range target shooters understand the benefits of a bullet with a high ballistic coefficient - they retain more velocity and therefore drop less and are less affected by the wind due to the fact that they get to the target quicker (and generally have a "sleeker" profile as well).

 What is "sectional density"?


Sectional density (SD) is defined as a bullet's weight, in pounds (7000 grains per pound), divided by the square of it's diameter in inches. A bullet with a higher weight in a certain caliber has a higher sectional density, and a smaller caliber bullet of equal weight to a larger caliber bullet will also have a relatively higher SD.

All else being equal (i.e., bullet construction), a high sectional density bullet will provide better penetration than a lower sectional density bullet.

 What's the best powder to use?


I use the following criteria in deciding what powder(s) to use ...
  1. "Tried and True" - some powders just work BETTER in some cartridges with certain bullets weights. Some manuals list "accuracy loads". Most firearm publications do so from time to time, and you can certainly get opinions on the various internet shooting forums.
  2. Go for 86-90% + loading density in your case. This provides more consistent powder ignition.
  3. Some powders, like the "Extreme" line, are less sensitive to temperature variations and are worth everyone who shoots in hot and cold environments' consideration.
  4. "Meterability" - how easy and consistently does it meter through my powder throw? Short stick and ball powders are very good in this respect.
  5. VERY IMPORTANT - which one does YOUR RIFLE / HANDGUN like? Every firearm is different. This is a "trial and error" proposition - but use the above to make your initial choices.
  6. A Tie-Breaker - which is the most economical? I found that my .308 Win likes IMR4064, W748, and AA2520 EQUALLY - but the AA2520 gives the best $$ economy per load, so I use AA2520 in my .308 Win.
  7. Another Tie-Breaker - which is the most versatile for your OTHER rifles/handguns? This way, you don't have ump-teen different open jugs of powder to store.


Does ammunition EXPLODE in a fire?


No, it deflagrates, and will not build pressure unless contained. Click here for more information.

What is the proper way to measure group size? Is it the extreme spread, measured center to outside edge; aimpoint to furthest edge, ?? ...

The standard method is to measure across the outside edges of the two holes that are the furthest away from each other, then subtract 1 caliber to normalize your measurement. This gives the center-to-center distance of the two furthest holes. For practical considerations in the field, your aimpoint should be adjusted so that it lies in the center of the group.

How many shots do you need to get a "reliable" group size? Well, I remember reading about the statistical validity of x-shot groups a couple of years ago. In the article, the author (??) claimed that the best efficiency between statistical validity and ammunition usage was 7 or 8 rounds. I don't recall the exact basis for all this, or what level of confidence he was seeking.

Now, from a practical standpoint, I look at it this way. Three shots is pretty lean, and 10 shots is certainly enough for us to see a trend. However, it really depends on HOW TIGHT those groups are. If one shoots 3 shots on top of each other - that's pretty durn good. "On top of each other" is subjective. Some folks might be happy with 1", others want 0.25". You might want to stop right there and shoot a new group to confirm accuracy. However, if 2 are touching, but one is an inch or more away, you need to see if the lone shot was a flyer. For this reason, an "open loop" feedback method has its merits, rather than blindly shooting x-shot groups all the time.

That said, I "blindly" shoot 5 shot groups. If I can put 5 shots in a good group, or 4/5 on top of each other (I'll suspect the lone shot to be a flyer), I'm pretty happy. Additionally, I won't rely on ONE 5-shot group. If I get one 'good' 5-shot group, I'll shoot at least one more group to confirm it.

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Last Updated : 28 February 2001