Bullet OAL and COAL CHARTS

[Tactical30]

What websites show you the correct COAL for all the different brands of bullets? The SPEER book I got only shows 40gr,50gr,52gr,55gr,63gr,70gr. bullets. I need the COAL lengths for 62gr,69gr,75gr,77gr etc. Is a Speer 52gr. HPBT bullet going to have the same COAL as a Sierra 52gr. HPBT bullet Etc,Etc. I would like to have a chart that shows all the different brands and bullet sizes and their COAL for them. I now there is one out there. I bought one off a website for a AR-15 and it cant be right because it said a 52gr Sierra HPBT bullet COAL was 2.250 and that cant be right. The speer book and the other books i read said it has a COAL of 2.200. Also it said for a 69gr. bullet is 2.260! Im new to this but that just doesnt sound right. I loaded a Sierra 52gr. to 2.250 and put it next to a Black Hills 77gr loaded bullet and it was just as long as it , if not longer! I know the Speer book is right at 2.200 but it doest have some of the bullets I need lenghts for.
I need a good, consistent bullet chart. Is there one out there?

 

[Fuzzball]

Re: Bullet OAL and COAL CHARTS

"What websites show you the correct COAL for all the different brands of bullets?"

There is no such site, there is no such "correct COAL" as you seek. No book's OAL is a "standard", it's not a "rule" and it's NOT the best seating depth to achieve best accuracy in YOUR rifle or handgun.

SAAMI sets minimum throat lengths based on the largest, heaviest round nose bullet likely to be used in the cartridge to assure it can be chambered and still be safe. Most makers actually cut the throats a bit deeper, depending on what they think will help keep reloaders outta trouble. Therefore, the thing determining maximum OAL is usually the magazine, not the chamber. Minimum OAL is a testing thing, for each rifle.

The OAL numbers you see in loading manuals are NOT specifically choosen for the listed bullets. It's ONLY the length they used to develop the powder data in their rifles, and their's is not ours. The rule, "Start powder charges low, and only move up if....etc" will accomidate any variable to a book load you may wish to make. Reloading is more of an art of rationally juggling variables than a 1-2-3 science.

 

[Victor N TN]

Re: Bullet OAL and COAL CHARTS

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">"What websites show you the correct COAL for all the different brands of bullets?"

There is no such site, there is no such "correct COAL" as you seek.


Reloading is more an art of rationally juggling variables than a 1-2-3 science. </div></div>

Well stated.

 

[ChadTRG42]

Re: Bullet OAL and COAL CHARTS

Think of it this way, different bullets have different ogive to tip lengths. A match BTHP or VLD bullet will have a greater ogive to tip length, which causes it to be seated out closer to the lands. A SP or RN bullet has a short ogive to tip length, and therefore would be seated deeper in the case having a much shorter COAL. So, it depends on the bullet you are shooting in the given caliber to know where to seat the bullet. That's why each mfg has a COAL listed in their reloading manual for their specific bullets.

Take a look at this Hornady link and look at the different bullet shapes. A 180 grain SP or RN bullet has a much different shape/profile than a 190 BTHP or a 208 A-max.

 

[MitchAlsup]

Re: Bullet OAL and COAL CHARTS

The problem, is that it is easy to measure a number which is almost irrelevent to the firing process, and difficult to mesure the number which is relevent to the firinig process.

OAL is the irrelvent number--relevent only ot whether the loaded cartrige fitsin the magazine. What IS relevent is the relation to the ogive-to-shank transition on the chambered cartrige to the rifling lands at the end of the throat. OAL is easy to measure, jump distance requires some tools or several precise measurements. This parameter contributes to the shape of the pressure rise curve early in the ignition event.

 

[Fuzzball]

Re: Bullet OAL and COAL CHARTS

"it depends on the bullet you are shooting in the given caliber to know where to seat the bullet. That's why each mfg has a COAL listed in their reloading manual for their specific bullets."

Chad, if you think the book makers actually experiment with the bullets, anyone's bullets, for what actually shoots best I fear you may be disappointed to learn the truth. All they really do is choose a reasonable lenght that will feed and shoot them for velocity with their choice of powders.

 

[ChadTRG42]

Re: Bullet OAL and COAL CHARTS

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">"it depends on the bullet you are shooting in the given caliber to know where to seat the bullet. That's why each mfg has a COAL listed in their reloading manual for their specific bullets."

Chad, if you think the book makers actually experiment with the bullets, anyone's bullets, for what actually shoots best I fear you may be disappointed to learn the truth. All they really do is choose a reasonable lenght that will feed and shoot them for velocity with their choice of powders. </div></div>

Where did I say the mfg's experiment with other mfg bullets and see what shoots best. I'm simply referring to the COAL for a specific mfg bullet.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">The OAL numbers you see in loading manuals are NOT specifically choosen for the listed bullets. </div></div>
And by the way, yes they are.

 

[randyp]

Re: Bullet OAL and COAL CHARTS

The 2.260" length you stated is max length to fit in a magazine if you are shooting an AR. If the cart. over all length is greater than that your rounds will hang up in the mag. Otherwise, refer to what the others have stated.

Randy P.

 

[Fuzzball]

Re: Bullet OAL and COAL CHARTS

"Where did I say the mfg's experiment with other mfg bullets and see what shoots best. I'm simply referring to the COAL for a specific mfg bullet."

That's not what I said, and so am I.

Sure, they pick a specific seating depth for what ever bullet they choose to use. But it's arbitary, often to fit a given magazine, not specifically chosen according to some mysterious standard. Therefore, it really doen't mean any more to us than their wide ranging start/max loads and projected velocities, it's a general guide and no more than that.

In application, the data our books give is generic. It's based primarily on the bullet weight and it can be used with just as much validity with anyone else's bullet of the same weight. They ALL recognise that when they say, "Start low and only work up..." etc. If reloading were a specific science they wouldn't <span style="text-decoration: underline">need</span> to say that!

AND, if there WAS any specific OAL we should be striving for with each individual bullet, there WOULD be a SAAMI, or what ever, chart for it. There isn't. That's because it wouldn't be relivant to any arm except the one used by the testor.

If we duplicate the OAL in any book we have only loaded a cartrige for the testor's rifle, etc., not our own. The ability to "custom" fit to what our arms need is a large part of what handloading is all about!

 

[ChadTRG42]

Re: Bullet OAL and COAL CHARTS

You need to work on your written comprehension. The bullet makers don't just pick a COAL to use, and it's not based soley on fitting it into a magazine or weight. It's based on the ogive of the bullet and what the COAL max should be to still function in a standard chamber with a certain bullet. Take a 190 grain SP or 200 grain RN bullet for the 308. COAL is 2.70". It's because the ogive of the bullet is much further forward than a BTHP bullet. If you seated the RN to mag length, it might not chamber in a given 308. And you can't base it on weight. A 150 grain RN is going to have a much shorter COAL than a 150 grain SST. There is COAL guidelines for each specific bullet.

 

[Fuzzball]

Re: Bullet OAL and COAL CHARTS

"..based on the ogive of the bullet and what the COAL max should be to still function in a standard chamber with a certain bullet."

"There is (sic) COAL guidelines for each specific bullet."


Certainly. But, much of what I'm addressing lies in the question, "What is a "standard" chamber?" And what makes it standard?

SAAMI only specifies (suggests, actually) a minimum chamber and throat/free bore. The arms makers are free to make throats as long as they wish. Quite a few make their throats much longer than the minimum, and even that varies a bit on different production runs. A proper seating depth for an individual rifle depends on the ogive AND the chamber/throat, not just the bullet taken alone.

Thus, the book makers have to pick a length that will fit THEIR rifle and throat, they can't figure in what your's might be. I doubt they find OAL by flipping a coin, surely they fit it into their pressure gun's chamber properly, but there is no (closely guarded?) COAL "guideline" about it. If any such existed, we WOULD have copies available; we don't have that because it doesn't exist. Even if it did, bullets come and go on the market so rapidly the guide would be obsolete as soon as it was printed!

And for sure we all have to take into consideration the ogive of our chosen bullets AND our own throat or we are mountain flying blind in a fog. The books simply give us a rational starting place and that's my point. Agree or not, as you wish.


"You need to work on your written comprehension." ???

Forgive me, I'm a shooter/reloader working stiff, my writing skills are not great. That doesn't change the facts.

(But, "written comprehension"? Shouldn't that be "writing clarity" vs. "reading comprehension"? Oh well...I'm sure YOU knew what you meant!

)

 

[Enios]

Re: Bullet OAL and COAL CHARTS

I Agree 100*, but in some cases we have found on a new 243 the book has us hitting the lands with a 85 gr SGK. Everyone should know where the ogave makes contact with lands and find what their rifle likes. I had a 223 you could just barely stick a 75 Hornady match bullet in the case neck and it still wouldn't touch the lands and it was also a brand new rifle which was returned. Wouldn't shoot a group under 2 1/2" with anything you stuck in it. When they sent it back without doing a thing to it other than firing a 3 shot group just under 2 1/2" and telling me that was within there standards for an Ultimate Varmint rifle it was traded off within 2 hours and I will never purchase another.

 

[Fuzzball]

Re: Bullet OAL and COAL CHARTS

"..in some cases we have found on a new 243 the book has us hitting the lands with a 85 gr SGK. Everyone should know where the ogave makes contact with lands and find what their rifle likes."

Enios, exactly so. You have very well illustrated my position that book OAL (for some non-existant "standard" chamber?) is a starting point, not a ballistically established fact!


"I had a 223 you could just barely stick a 75 Hornady match bullet in the case neck and it still wouldn't touch the lands and it was also a brand new rifle which was returned. Wouldn't shoot a group under 2 1/2" with anything you stuck in it. When they sent it back without doing a thing to it other than firing a 3 shot group just under 2 1/2" and telling me that was within there standards for an Ultimate Varmint rifle it was traded off within 2 hours and I will never purchase another."

Sorry about your problem. I do wonder if you might have rejected the rifle too soon. It is NOT true that "most" rifles shoot their best when loaded to, or even near, the lands. In fact, most factory rifles I've worked with shoot best from at least .030", never closer, and as much as .125" off the lands. It takes experimentation to find what works.

Bad groups from a good rifle is quite often due to mis-matchhed bullets. Hornady's Match Bullets are very good but they're not going to be ideal for every rifle. Changing bullet brands has solved many such poor accuracy problems but a 2 1/2 incher had a LOONG way to go! Ah well, it's a done deal now isn't it!

Good luck.