C.O.A.L.

[Will-j]

HIG; No offense taken. It's just that a lot of technical info/data is not explained in the manuals and therefore is not readily interpreted or easily understood. The very reason that the manual/component manufacturers and at times, the people who contribute some data to these companies are a little... NO.... Read that quite upset with me for asking the MANY questions I have when some of the stuff written in their manuals made/makes no sense whatsoever. Understand....people are only human [Redundant... I know], and make mistakes. Bringing it to their attention helps correct further publishing of the same mistakes/misprinting of errata, etc. with no offense meant toward them. After 40 yrs. reloading, I have made too many mistakes to remember them all but rest assured, I very rarely have made the same mistake twice- [mostly have caught myself]; NEVER a third time. Take care HIG.

T O'HEIR; I don't know how long you've been reloading, or even care; But before you make another blanket statement as you did RE: bullet cannelures/crimping grooves, you need to do some deep research and come to understand that they are put there for a purpose; TO CRIMP THE BULLET IN THE PROPER POSITION. And...TO KEEP THE BULLET FROM JUMPING CRIMP AND TYING UP THE CYLINDER OF THE REVOLVER UNDER RECOIL. Granted...some [LEAD] bullets in light loads can be taper crimped if done correctly without easing out of the case under recoil, and pistol loads for semi-autos don't [normally] have to be crimped because the cartridge head spaces on the case mouth (exceptions being the few bottle-neck cartridges out there today), therefore the taper crimp for them. Some loaders prefer to headspace the bottleneck cases on their shoulders and crimp the bullets in place [as in rifle cartridges] for added insurance.

It is stupid/ignorant/incorrect blanket statements such as uttered by you that may very possibly cause some new reloader to the scene to tie up his revolver by following your assinine [my SIC--if you get my drift] statement.
I'll tell you this: Follow your own advice; Load some medium to heavy loads with some heavy, jacketed bullets...DON'T crimp them...And after firing (or trying to fire) a full cylinder, tell us how many times the cylinder locked up from bullets jumping their cases...If you dare. As it stands, I am willing to bet you could tell us the color of your fecal matter from where your head now resides.

IF you've been reloading as long as I have and not learned WHY those cannelures and crimping grooves are on the bullets in the first place... you need to get out of the reloading scene before you get someone hurt...Even yourself.

Moderators: if you are monitoring these posts and not advising posters such as the one immediately above as to the inaccuracy of some of his/their posts, then I feel you are doing a disservice to the rest of the forum readers [both new and regulars] who depend on good, intelligent advice. If, on he other hand, you feel [that] I am in the wrong...Tell me and I will gladly voluntarily remove myself from the forum. I've seen too many get hurt from advice such as that given by some of the posters on quite a few fora. It does not need to be.

If I have offended anyone else on this site, I offer my apologies. However. sometimes, something needs to be said and corrected when inaccurate advice is given solely on the opinion of someone who is not fully aware of the damage and consequences which can occur from those ill-advised opinions. Facts are needed.. not opinions (unless properly noted beforehand) so that those seeking advice won't make an unfortunate mistake, possibly hurting themselves or someone else in the process.

WILL.

[mehavey]

- Revolver bullets are not seated to the crimp groove.
- The crimp groove means nothing.
- Most revolver cartridges DO NOT require a crimp at all

I have to admit that I am more than taken aback by each of these statements.

In reverse order:

If I do not securely crimp medium-high recoiling revolver cartridges -- especially w/ lead bullets -- I will progressive have bullets walk out of the case. Not only are velocities lower to start (w/o a crimp), but velocities increasingly fall off as successive bullets are fired while effective case volume is increasing.

The crimp groove is very definitely there for a reason. Without it you are jamming the case mouth into the bullet wall -- deforming both. And if you are seating/crimping at the same time, you are completely deforming/collapsing the case as the press completes its stroke against a bullet trapped in the case mouth.

Revolver bullets are then seated so as to properly engage the crimp groove; and the charge (if near MAX) is adjusted accordingly for pressure purposes.

.

[green_MTman]

fooling around with C.O.L is for rifle shooting. often where the more accurate load is achieved by sacrificing magazine.my loads wont fit in my magazine so my rifle has a internal box mag but i treat it as a single shot.

people who like magazines shoot 30-30's


there is never any reason to change COL on any handgun

[polyphemus]

Just to muddy the waters a little bit,all bullets that are the same caliber and weight have equal sectional density regardless of the material they are made of however that does not hold true of bullet lenghth,a plated or lead cast bullet is
shorter than a jacketed bullet of the same weight .020"+ in some cases.It follows then that a jacketed bullet seated to the same COAL as a plated bullet
will be deeper inside the case by the difference in lenghth between the two.

[Will-j]

POLY: You are correct. Further; The composition and (Brinell hardness) of the plated bullet's core, due to tin and other alloys often gives the bullet more weight from a shorter length, plus the copper plating is generally lighter than a copper/zinc jacket.

The softer core of a plated bullet obturates more easily and raises higher pressures, thereby necessitating (sometimes) an OAL the same as or longer than a jacketed bullet. [The shorter plated bullet allows more shallow seating with the same powder weight and thus either lower or equal pressure]. Think a longer OAL for the same bullet and powder. the longer the length with regards to safe chambering...the lower the pressure. Obviously. the converse is also true. Seat the bullet deeper and the pressure rises.

WILL.

[mehavey]

You guys are over-thinking this.

[higgite]

There's a difference between over thinking it and thinking it over. This thread may be doing both. Either way, better'n doing neither.

[AL45]

I shoot a Hunter brand 357 grain cast lead bullet in .45 Colt that has 2 cannelures. The load I use calls for 19-21 grains of H110 and lists a minimum OAL. If I crimped in the top cannelure, it would be below minimum overall length, and since this is a very hot load, could build up extreme pressures. I always crimp in the bottom cannelure which is actually longer than the listed COAL, but my Blackhawk cylinder is long enough for it.

[Unclenick]

Originally Posted by T. O'Heir

Revolver bullets are not seated to the crimp groove. The crimp groove means nothing. Most revolver cartridges DO NOT require a crimp at all. And are seated to the OAL given in the manual.

Well, most revolver bullets are made so the crimp groove is at the case mouth when you reach manual's stated COL, so the first and last sentence contradict one another in that case. As to not crimping at all, while I think that's an unwise default position, I can think of examples where it is true. My father recently gave me his near-mint condition S&W m. 1955 in .45 Auto/Auto Rim, and 230 grain hardball, which has no crimp, shoots without problems in it, same as they did in the model 1917 military revolver. At the other extreme, I have a friend who bought a titanium short nose revolver in .45 Colt years ago, and he found he could not shoot even crimped factory 250 grain loads in it without the bullets backing out and jamming its rotation; and this is a big guy with massive hands. He had to settle for 200 grain loads in that gun to be able to get through a cylinder full.

What happens when bullets back out in a revolver is recoil sharply smacks the cylinder back against the cartridge case rims. The inertia of the bullet mass wants to keep it where it is, so that smack causes the brass to try to pull off the bullet. When your wrist returns the gun to position, that's a much slower, lower force event, so the "pantsed" bullet stays forward. This is the same thing that happens in an inertial bullet puller, except cases are jerked back instead of bullets being thrown forward.

There is a threshold for the above behavior. The heavier the gun is, or the milder the load, the lighter the smack against the cylinder rims, so you can get below the threshold that breaks the static friction between the bullet and case, and then have no problem with it. A lubricated lead bullet will have less friction with the case than a jacketed bullet will, so it is more likely to be a problem shooting lead. The 2.5 lb m. 1917 and the moderate power level of military issue .45 ACP ball ammo made that combination work out.

To see how much of an issue it is or isn't in your gun, measure a cartridge's length before putting it and another just like it into your revolver. Position them so the unmeasured round turns under the firing pin first. Shoot only the unmeasured round and eject and measure the first round. Repeat four more times using the same measured round. If the length of that measured round grows any, you need more of a crimp. If not, your round may be below the threshold for the weight of your revolver. Just be aware that going to a lighter revolver with the same load may change that situation.

Originally Posted by Will-j

Moderators: if you are monitoring these posts and not advising posters such as the one immediately above as to the inaccuracy of some of his/their posts, then I feel you are doing a disservice to the rest of the forum readers

Unfortunately there aren't enough hours in a day for us to see every post on the board. I haven't got back to this thread since my last post in it. In general, this is the Internet, so, same as on any other part of the Internet, you believe what you read at your own risk. Caveat emptor. It's also the case that a lot of things folks think are absolutely true or absolutely false turn out to be true sometimes and not others, as my two examples of .45 Auto and .45 Colt chambered revolvers demonstrate. That's something else for readers to watch out for.

Regarding seating depth, it is, as you say, the amount by which the bullet extends into the case mouth. The significance to pressure, though, is not directly from the seating depth itself, but rather how much powder space it leaves under the bullet. The reason to keep this distinction in mind is that if I have a trimmed case and a longer untrimmed case that are otherwise identical, then loading to the same COL with identical bullets actually matches the size of the powder space, despite the individual seating depths being different by the amount of difference in case lengths.

For that reason, if you calculate seating depth, do so using the same case length every time. I use the SAAMI max, regardless of actual case length, then regulate powder space by keeping COL constant. You could just as reliably use a book trim-to length. Whatever you choose, stick with it.

Seating Depth = Case Length + Bullet Length – COL

If you have a seating depth calculated from the above equation for one of your bullets, and you are trying to find a new COL that gives a different length bullet the same seating depth, then just rearrange that formula to find the new bullet's COL as:

COL = Case Length + Bullet Length – Seating Depth

[Bucksnort1]

Mehevey,

You are right about over thinking. I find that to be true about many threads. They fall in the category of, "TMI", Too Much Information.

[44 AMP]

Shoot only the unmeasured round and eject and measure the first round. Repeat four more times using the same measured round.

My method is a little more simplistic, and I think valid. Measure, load 6, shoot 5, measure. Given the usual way I shoot, odds are low any individual round will get more than 5 shots before it has its turn.

If the bullet jumps crimp, adjustment is needed.

There are several combinations of gun & load that do not need a crimp. As well as combinations where a given amount of crimp isn't enough. Loads need to be tailored to the circumstances.

I once tested uncrimped loads in a couple guns and calibers. Standard velocity .45 Colt 250gr 7.5" Ruger Blackhawk. No crimp. last round did "pull" a noticeable amount, but not enough to reach the front of the cylinder. A heavier load, or a lighter gun would mean more bullet jump, possibly enough to jam the gun.

.38 Special 158gr lead, 850fps no crimp 6" S&W M28. No bullet movement.
same load Colt Agent snub, noticeable bullet movement, but again, not enough to jam the gun.

These results only apply to the ammo I loaded and the guns I shot them in, and your results could be different. Using a proper crimp avoids the issue, entirely.

[Unclenick]

My reasoning behind the two-bullet test was to have the gun lighter to create an extra margin for error. I figure the actual amount of pull would show some mean and standard deviation of value if I measured the 5th round ten times, but that by putting some extra oomph on the pull, I'd have something closer to a worst case maximum.