Of cannelures, ogives, lands, and OALs


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<SLV>
January 9, 2008, 07:44 PM
I'm getting ready to load my first .30-06 cases for my Tikka T3. I ran an empty case with bullet (150 gr. Hornady FMJ/BT) through the action to determine a length of 3.325" at which the ogive contacts the lands. I have decided to load for an OAL of 3.3", but when I set the bullet at this length the cannelure is significantly above the case neck.

1. What good is a cannelure if I'm not crimping?
2. Is there any problem with leaving the cannelure exposed?
3. How do I know if enough of the bullet is in the case?

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rg1
January 9, 2008, 08:14 PM
Hornady Manual 5th Edition lists an overall length with the 150gr bt-fmj at
3.260". Hornady 7th Edition Manual lists an overall length for the same bullet at 3.185" and has this bullet in its 30-06 pages and in its M1 Garand data pages. For the cannelure to be correct for the 30-06 case the 3.185" length is correct. At 3.260" the cannelure is forward of the mouth and your 3.300" will be even further out. I've shot both lengths in M1 Garand rifles and both feed and function ok with little or no change in accuracy. However the general rule for the amount of bullet needed to be inside the case for adequate bullet-case tension is one caliber for the caliber you're shooting. So if that rule is correct you need approx. .308" of the bullet inside the mouth. That would'nt apply to the boat tail, just the major diameter of the bullet. The same would apply to bullets that have no cannelure. I'd test these bullets in your 30-06 bolt rifle at varying lengths from the 3.185" up to your chosen length just to test for what's most accurate. A couple of my hunting rifles prefer bullets seated 30-35 thou off the lands for best accuracy with my components. Seated closer or further off the lands and spread opens a little. No problem leaving the cannelure outside the mouth if you have adequate bullet tension in the case. This Hornady bullet and the cannelure location and their change of o.a.l. is unusual yet they show this bullet with nearly all 30 caliber rifles so I guess the cannelure can't be correct for all.

USSR
January 9, 2008, 08:25 PM
1. What good is a cannelure if I'm not crimping?

It really does no good if you aren't using it. But, that being said, I never crimp rifle bullets and I shoot cannelured bullets without crimping.

2. Is there any problem with leaving the cannelure exposed?

Nope.

3. How do I know if enough of the bullet is in the case?

The rule of thumb, is to leave atleast 1 caliber (.308) of the bullet in the case.

Don

<SLV>
January 9, 2008, 08:49 PM
I've heard that bolt guns will achieve the best accuracy with the bullet 0.025-0.050 off the lands. Does anyone else have a recommendation for tuning the ammunition's AOL to my specific gun?

esheato
January 9, 2008, 09:10 PM
Sure....;)

Experiment with your rifle. It'll become apparent which direction it likes bullets.

Ed

USSR
January 9, 2008, 10:37 PM
<SLV>,

If you don't already have it, buy the Stoney Point/Hornady OAL Gauge and a modified case, and determine just exactly where your throat is. Having your bullet .010" to .015" off the lands is a good place to be.

Don

azar
January 10, 2008, 10:12 PM
USSR,

Is there a reliable way to measure without using those tools. Maybe something similar to what is talked about in this thread? (http://www.thehighroad.org/showthread.php?t=266823) The main reason I ask is that I've about hit my limit "saving money" reloading. :rolleyes: There never seems to be an end of all the neat gizmos you can burn your paycheck on to make your rounds that much more accurate.

Note: I believe the "Stoney Point" brand no longer exists. In the Midsouth Shooters Supply master catalog they show "Hornady Lock-N-Load Bullet Comparator and O.A.L. Gauges (Formerly Stoney Point)". So it looks like Stoney Point my now be owned by Hornady. Or perhaps the bought the rights to those tools, who knows.

birdbustr
January 10, 2008, 10:27 PM
I have a bullet comparator set that I got for about $30. I do know of a cheap way to test how deep the lands/grooves are.

1. Take a empty casing from whatever caliber gun you want to know about, cut 2 or 3 slots in the neck of the case. This will allow the bullet to still hold in the case.
2. Take one of the bullets and a lighter and blacken the bullet (use a larger grain bullet) from the smoke.
3. Insert the blackened bullet into the slotted case, chamber slowly and then carefully eject the round out so you don't disturb the position of the bullet.
4. Measure where the lands and grooves show on the blackened bullet from the bottom of the case to the marks. There you have the depth of your lands and grooves.

USSR
January 10, 2008, 11:02 PM
azar,

Yes, Hornady bought Stoney Point, that why I called it "Stoney Point/Hornady OAL Gauge". Are there other ways? Sure. How precise, reliable and repeatable are they? Not very. Yes, the gizmo's do cost you $$$.:D

Don

Bitswap
January 10, 2008, 11:31 PM
IMO, you should know your maximum coal and cartridge length should be. The stoney point, or hornady, is pretty good at determing this and very repeatable if you have a light touch.

Consider that these are maximums. The former being dangerous if you don't trim correctly. There are some home-made solutions to obtain these measurements that work well.

Also consider that a bullet 'on the lands' may not be optimum. IMO, finding the harmonic or OCW is the best way to go. For my 308, 0.030 behind the lands is the sweet spot for the powder measure I use. Seating on the lands can really mess things up as well. Ever go over a speed bump when your were on it vs a running start? Same thing happens with a bullet.

Sierra has been very good about their coal and seem to be perfect. That's where I'd start and increase/decrease by either 0.010 or 0.003 depending on how many times you want to go to the range.

Hope this helps,
Bit

azar
January 11, 2008, 03:30 PM
USSR,

Ooops! I hadn't notice the mention of Hornady in your post. :o

My fear is buying these tools and then not being able to use them correctly or using them correctly but not really being able to tell a difference in accuracy. I guess mainly what I'm getting at is the fear of buyers remorse at having purchased something that I didn't really need.

Plus, I have a kid on the way and my disposable income is no longer disposable. :uhoh: :)

Oh, and the soot / dry-erase marker on the bullet trick has never worked for me. I'm not sure I have ever seen evidence of the lands... But I have never tried cutting 2 or 3 slots into the case neck. I've just been going off "Does the bolt close easily? This is the starting point." Which may not be the best method. I had to do that on some Sierra 160g round nose loaded in 6.5x55SE. Sierra had the C.O.A.L at 3.050" which wouldn't chamber easily in my gun with that particular round. I decided to simply drop it down to 3.025" (a common length for reloads for this caliber) which chambered nicely and has patterned quite well. But I'm to much of a perfectionist to not know if it could get even better...

ny32182
January 12, 2008, 04:27 PM
Well I've got a strange set of circumstances here... I'm loading the same Hornady 150gr FMJ in .308. I've got the cases trimmed to just over the listed "trim length". I'm seating the bullet and at the recommended 2.78" OAL, the cannelure is fully exposed? Indeed it is.

I thought this bullet would have been made specifically for .308 for the mostpart?

I intend to shoot this ammo in an FAL, should I just Lee factory crimp die it afterward and call it good?

USSR
January 12, 2008, 05:11 PM
ny32182,

Ignore the cannelure. BTW, I load for my FAL with a 2.81" OAL (the longest that will fit the magazine), and most of the bullets I load don't even have cannelures. As long as you have sufficient neck tension, you don't need to crimp. Holding a loaded cartridge upside down with a finger on each side of the case, pressing the bullet tip into a table top, if the bullet doesn't move, you've got enough neck tension.

Don

ny32182
January 12, 2008, 05:37 PM
Thanks..

ny32182
January 14, 2008, 08:28 PM
So I've got another question..

When I was first tearing down and reseating Paki surplus, I was getting varying OAL's, which I thought was fine since the bullets were inconsistent, both visually, and when weighed.

However, I'm having the same thing happen with the new Hornady FMJ bullets. Varying OALs. Nothing that will cause a KB, and I'm running them a little longer than the load data suggestion, but I'd say the extreme spread I'm seeing is nearly .01". These bullets are weighing to within 2/10ths of a grain of each other, and the shape of the forward portion of the bullet "looks" the same to me on each one.

I only mention it because my .223 loads using similar Hornady FMJ's are coming out very consistent (comparatively at least). I seem to recall an extreme spread of .002" or .003".

Could something be wrong with my seating die? There is something I'm not getting here.

USSR
January 14, 2008, 08:34 PM
Could something be wrong with my seating die?

No. Your seating die seats the bullets near the bullet ogive and not the bullet tip. This is as it should be, as the place where your bullets contact the lands is at the ogive, not the tip. Don't worry about the varying OAL, as long as they are not running too long to fit your magazine.

Don

ny32182
January 14, 2008, 08:48 PM
So you'd guess the root cause is just inconsistency in the shape of the ogive that I can't see with the "naked eye"?

ny32182
January 14, 2008, 08:50 PM
double tap

taliv
January 14, 2008, 09:29 PM
no, the ogive is probably pretty consistent. the length of the tip (meplat) is what is most likely varying. general consensus is that deviations in OAL measured from the tip have no measurable impact on accuracy HOWEVER, sinclair and others sell "meplat trimmers" so you can fix it if you wish.

ny32182
January 14, 2008, 09:57 PM
Can I get an exact definition of ogive, meplat, and/or any other dimensions that might be useful to know about? :) A diagram, maybe?

Thanks for all the info so far...

USSR
January 14, 2008, 10:16 PM
taliv is correct, it's the bullet tip locations that vary. Ogive is the portion of the bullet where it starts to curve away from the .308" part of the bullet and narrow as it progresses towards the tip. The only part of the ogive that concerns us, is the part where it narrows from .308" to .300", since this is the part that contacts the lands. Having your ammo with all the bullet ogives located the same distance from the lands is more important than having all your ammo with the same OAL.

Don

ny32182
January 15, 2008, 12:00 PM
If I'm getting different seating depths though, and the ogive is what is contacted by the seating die, wouldn't that mean that either the ogives have to be inconsistent, or something is going on with my die?

taliv
January 15, 2008, 12:09 PM
no, it means you're measuring from the tip of the bullet.

what you need is a little doohickey that you put on your calipers to measure OAL from the ogive. i'll try tofind a link for you in a moment



edit: try this http://www.sinclairintl.com/cgi-bin/category.cgi?category=RESDTCO&item=09-700&type=store

notice in the picture how the tip of the bullet is poking through the little metal gadget. the bullet is contacting the metal gadget the same as it would a barrel (it has 6 holes for 6 calibers)

ny32182
January 15, 2008, 12:21 PM
Ahh... gotcha. So it is an inconsistency forward of the ogive. I see.

<SLV>
January 15, 2008, 12:35 PM
Cool tool, that comparator, but how do you get an exact measurement of your chamber from boltface to lands? You would have to know this in order to know your ideal measurement on the comparator. I had a friend tell me to seat a bullet by closing the chamber, but that seems somewhat crude.

taliv
January 15, 2008, 01:14 PM
yep, the inconsistency is on the very tip itself.

stoney point sells a popular reasonably priced tool to do that, slv. sinclair sells some pricier versions

this is the one i use
http://www.sinclairintl.com/cgi-bin/category.cgi?category=RESDTSD&item=59-4000&type=store
http://www.sinclairintl.com/cgi-bin/category.cgi?category=RESDTSD&item=09-4X&type=store

(edit: i don't know what's up with the "new style" "old style" crap... but mine looks like the combination of the two pictures you see there... the rod with two stops on it, and the nylon slider that goes over the rod and has the little metal shaft sticking out the side)

USSR
January 15, 2008, 08:30 PM
Cool tool, that comparator, but how do you get an exact measurement of your chamber from boltface to lands? You would have to know this in order to know your ideal measurement on the comparator. I had a friend tell me to seat a bullet by closing the chamber, but that seems somewhat crude.

Again:

<SLV>,

If you don't already have it, buy the Stoney Point/Hornady OAL Gauge and a modified case, and determine just exactly where your throat is. Having your bullet .010" to .015" off the lands is a good place to be.

Don

redneck2
January 15, 2008, 09:18 PM
Easy and cheap answer to "bullet on the lands"

1)..As mentioned, cut a case on each side of the neck down to the shoulder with a dremel.

2)..drill the flash hole out large enough so the blade of a pocket screwdrive fits thru it

3)..seat a bullet out too far out

4)..open the action and insert the round with your fingers

5)..using the screwdriver against the outside rim, push the case tight into the chamber, then put the screwdriver thru the hole and gently push the bullet forward to the lands

6)..remove the round with a cleaning rod

I put nail polish on it to lock the bullet in place. You now have a bullet that seated at .000". Use this to set your bullet seating die. (Check OAL to make sure the bullet doesn't move) . Keep this dummy bullet round for reference.

FWIW...there are a lot of useless toys for reloading. The Stoney Point gauge is one of the best investments I've made

Khornet
January 16, 2008, 01:13 PM
is simple, reliable, repeatable. That plus one of their comparators will give you precisely loaded ammo. AND you don't have to get "specially modified" cases to do your measurement. Instead you use a case fired in YOUR rifle.

IMHO those tools are a basic necessity for those wanting to load rifle ammo. Not too spendy, and they last forever. Saves a lot of wasted time on trial and error.

As the years take their toll on my 03A3, I repeat this measurement from time to time, and have been able to see how erosion has slowly increased the length to touch the lands.

As for the soot-on-the-bullet trick, I've tried it several times on various guns and never found it to work.

azar
January 16, 2008, 10:23 PM
redneck2,

Thanks for sharing your method of measuring the o.a.l. without using an o.a.l. gauge. It's similar, but a little different (aren't they all), from others I've heard.


Khornet,

I'm glad I'm not the only one who hasn't gotten the soot / dry-erase marker trick to work! I felt pretty stupid after trying multiple times across a couple of different evenings.


For those of you who have bullet comparators and o.a.l. gauges. which one would you recommend? The Sinclair or the Hornady, and why?

taliv
January 16, 2008, 10:27 PM
seemed like khornet explained it pretty well. the sinclair tool does not require special cases, which means it works in any gun, any caliber with no fuss.

azar
January 16, 2008, 10:41 PM
taliv,

There's no difference in accuracy without the special cases? Sorry if that's a noob question... :rolleyes:

Bullet
January 16, 2008, 11:34 PM
ny32182
Can I get an exact definition of ogive, meplat, and/or any other dimensions that might be useful to know about? A diagram, maybe?

From SAAMI’s Glossary -

OGIVE
The curved portion of a bullet forward of the bearing surface.

http://www.saami.org/Glossary/index.cfm

Bullet
January 16, 2008, 11:46 PM
While this is not what you asked for you might consider this (copied from another forum)-

“There are some pretty universal rules about seating a bullet. You first seat the bullet to a given depth and then work up with the charge. To do otherwise might lead to a pressure excursion. Do you know how to read pressure in a rifle case??? If the radius of the primer is gone,the bolt lifts hard,you can see the extrusion of brass back into the elector hole,see the machine marks on the bolt face in the brass or the primer flat falls out of the case the load may be a bit hot. BUT, this can and will happen regardless of where the bullet is seated if you tip the powder bottle too much. Here's a very easy way to develope a load:
1)-Set the bullet into the lands(if you can reach them) as much as the neck tension of the case will allow.
2)-Start with a minimum listed powder charge-10% for the bullet weight
3)-Work the powder charge up till the groups get as small as they will get.
This depends on the rifle.
4)-After getting as small a group as the rifle will shoot at the jam,back the bullet off.002/.003 at a time and see if the groups improve.Depending on the rifle they may or may not.
5)-If you decide on trying another bullet back the powder down and go back to the jam length and start again.
What this saves is guesswork. If the bullet is seated HARD into the lands then the only way to go with it is shorter. If the bullet is seated HARD into the lands and you have a safe working load pressures will NOT increase as the seating depth is shortened. If you, at any point,. get pressure signs, STOP. Back off the powder and start up again and see if it repeats. Be aware that a load shot at 70 degreesF. may not be a safe load at 100 degrees F.Back a load off when you change ANY part of that load including changing lots of the same brand of powder. Never assume anything;prove it to yourself. There is not really a lot of rocket science in rifles; experience is much more important”

taliv
January 17, 2008, 12:06 AM
2)-Start with a minimum listed powder charge-10% for the bullet weight

i've always started with the minimum OR the maximum -10%.


There's no difference in accuracy without the special cases?

dunno. with the sinclair tool, there's not really a question because you're using the brass you're going to be shooting.
with the stoney point tool, i guess there's a question but i've never heard anyone complain about it, so I really doubt there's an issue. afaik, like most things in reloading, it's ease of use vs cost

Bullet
January 17, 2008, 12:13 AM
2)-Start with a minimum listed powder charge-10% for the bullet weight

taliv
i've always started with the minimum OR the maximum -10%.

I believe that is what he meant. Probably should have said -

2)-Start with a minimum listed powder charge or -10% for the bullet weight

Khornet
January 17, 2008, 07:22 AM
in the Sinclair tool and comparator, you'll get a useful set of tools that you'll be able to use on multiple guns for decades. Very handy when changing bullets or guns. You can do just fine without it, but it really adds to the fun.

USSR
January 17, 2008, 07:50 AM
Here's a very easy way to develope a load:
1)-Set the bullet into the lands(if you can reach them) as much as the neck tension of the case will allow.

I realize that these are not your words, Bullet, but IMHO, starting out load development by jamming your bullet into the lands is downright dumb and potentially dangerous to someone who doesn't know what they are doing. There are basically two scenarios that you find in load development in rifles: 1. the throat is located beyond what the magazine length is (so load to an OAL to fit the magazine); and 2. the magazine is long enough to accomodate an OAL that will reach the throat (so play with OAL's that vary from .010" to .020" off the lands).

Don

Bullet
January 18, 2008, 03:03 AM
USSR
IMHO, starting out load development by jamming your bullet into the lands is downright dumb and potentially dangerous to someone who doesn't know what they are doing.

I don’t think working up a load from jam is dumb and that reloading could be potentially dangerous to someone who doesn't know what they are doing. But you still might have a valid concern. Maybe starting at jam should be left to experienced reloaders.

<SLV> and any other new reloaders reading this - I wish I had a place like THR to ask questions when I was starting to reload. If you’re not sure about something ask questions here. I’m sure you will get some good advice, and remember, there are no dumb questions.

If you enjoyed reading about "Of cannelures, ogives, lands, and OALs" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!