30-06 maximum OAL


PDA






RB98SS
October 27, 2009, 01:39 PM
I need some education here.

If I can take a fired, deprimed case and insert a bullet of my choice seated shallow, slowly chamber it in my rifle (30-06 A-Bolt), and measure the cartridge maximum OAL (minus .005-.015) for that particular bullet. Why would I want a Stoney Point gauge or the like? Am I missing something?

Secondly, if I do the procedure above using a Barnes 168 TSXBT, I get a reading of 3.375. Is that a accurate measurement to determine the seating depth to the lands?

Barnes recommends that you start .050 off as a starting reference to use for trying to determine accuracy but that still puts me too long to fit my magazine and over SAAMI spec for this caliber doesn't it?

Thanks for the lesson,

Gary

If you enjoyed reading about "30-06 maximum OAL" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
Vern Humphrey
October 27, 2009, 01:53 PM
If I can take a fired, deprimed case and insert a bullet of my choice seated shallow, slowly chamber it in my rifle (30-06 A-Bolt), and measure the cartridge maximum OAL (minus .005-.015) for that particular bullet. Why would I want a Stoney Point gauge or the like? Am I missing something?
The Stony Point gauge is more accurate and produces more repeatable results. But your method will work just fine. If you get too much slippage, try wrapping the bullet shank in toilet paper.

Remember, the measurement you get this way is fine for that bullet. You will have to repeat the process if you switch bullets.
Secondly, if I do the procedure above using a Barnes 168 TTXBT, I get a reading of 3.375. Is that a accurate measurement to determine the seating depth to the lands?
It should be -- but take several measurements. If they are all close to that figure, you're in the ball park. If you have some measurements that are markedly different, you're getting bullet slippage.
Barnes recommends that you start .050 off as a starting reference to use for trying to determine accuracy but that still puts me too long to fit my magazine and over SAAMI spec for this caliber doesn't it?
Yep. It's not uncommon to find that a bullet seating depth that puts you right at the lands will be too long to feed through the magazine.

One solution is to look for a bullet with a shorter nose. In the .22 Hornet, for example, I use the 35 grain Hornady V-Max. It has the same shank length as the heavier bullets, but a shorter nose, allowing me to put the shoulder of the bullet right at the lands and still feed through the magazine.

USSR
October 27, 2009, 02:10 PM
Barnes recommends that you start .050 off as a starting reference to use for trying to determine accuracy but that still puts me too long to fit my magazine and over SAAMI spec for this caliber doesn't it?

There is no SAAMI spec for cartridge OAL. The OAL listed in reloading manuals is simply the OAL they used with that particular bullet. And, yes, Vern is correct; the Stoney Point OAL Gauge will give you more accurate measurements.

Don

RB98SS
October 27, 2009, 03:03 PM
Thanks for the responses guys.

I do have one more request if I may. You guys both seem to think that a gauge like a Stony Point would get more accurate results. Would it be possible to explain how a gauge actually works and what makes you feel the way you do about them. I have no idea how it works.


Thanks again.

NCsmitty
October 27, 2009, 03:05 PM
If you want to use your magazine, that dimension will be the limiting factor. COAL is only a recommended dimension and is not etched in stone.
Most '06 magazines will handle 3.300.


NCsmitty

rcmodel
October 27, 2009, 04:59 PM
There is a SAAMI spec for maximum cartridge OAL.
It is shown in the drawing at the top of the load data in most reloading manuals.

All it means is, that is the accepted max length for any bullet in that cartridge and still work through all magazines and actions.

It has no bearing on the proper OAL for a specific bullet weight or shape.

The OAL shown in the manual under each specific bullet is the OAL the test data was shoot at. It should work fine in any rifle, although seating further out may help accuracy.

Or not.

rc

RB98SS
October 27, 2009, 07:30 PM
Thanks guys, I'm still wondering how the OAL gauge works and how it makes the measurement more accurate.

ranger335v
October 27, 2009, 08:25 PM
I believe USSR meant there is no binding OAL, and on that we all seem to agree. 'Cause it's true.

Since few factory sporters shoot best seated into the lands and since Barnes wisely suggests some 50 thou off the lands, finding the lands precisely is an expercise without value. Get it sorta close then back off say 30 thou and experiment by moving out in 5 thou steps until you find the best shooting depth. And, to keep OAL simple, just measurure it from head to meplat (bullet tip).

Going to the expense of buying a special tool to measure seating depth off the ogive IS meaningful for BR shooters seating at or into the lands but it really isn't very helpful for the rest of us. The best shooting OAL for factory rifles will be a range, not a specific spot. Find the range that makes no difference and seat in the middle of it, then normal small seating variations won't matter until the rifling errodes. Then, when groups go bad just seat out bit more and things should correct.

Ol` Joe
October 27, 2009, 08:34 PM
Your way jams the bullet in the rifling a little when chambered and it will pull back out of the case slightly when you extract it from the riflings grip on it. The gages use finger pressure to lightly push the bullet in the barrel until a slight resistance is felt. Both will work though and are simply a reference for you to work from when tuning your load to the rifles OAL preference.
The real point you need to measure and accuracy here counts, is the get the base to ogive length of your cartridge once you find what the rifle likes. Measuring from tip of bullet to base of brass isn`t near enough accurate and repeatable. The Stoney Point or Sinclair comparators are IMO a must for this.

NCsmitty
October 27, 2009, 09:35 PM
FYI, Stoney point was bought by Hornady. Here's a link to 6mmBR site overview. It may give you a little more insight on its use and value to you.

www.6mmbr.com/catalog/item/1433308/977259.htm



NCsmitty

rcmodel
October 28, 2009, 02:47 PM
An alternate old-school method I use is to seat the bullet long.
Then smoke the bullet with a candle flame.
Attempt to chamber it and note the rifling scrapes on the candle soot.

You can continue to seat very slightly deeper, re-smoke, and re-chamber until no rifling marks appear in the soot and you are at exact zero clearance.

I would have to be convinced that a Stony Point gage is any more accurate.

rc

Beelzy
October 28, 2009, 04:02 PM
Yep, Old School works just fine.

GP100man
October 28, 2009, 04:18 PM
I got caught doing a no no, I seat my bullets similar & got a different lot of same bullet made fifty for the season & not a 1 would chamber but another .010 got me by!!!

RB98SS
October 28, 2009, 05:16 PM
Thanks again guys, informative as usual.

tomt
October 29, 2009, 06:59 AM
I use a Hornady O.A.L. gauge for my .243, .270 and .30-06. I stand on the opposite side of the bolt (left) when doing this. I insert a wooden dowel rod in the barrel, seat the bullet deep into the modified case and insert into camber. Loosen set screw and with right index finger hold pressure on the back of the case. I use my right ring finger to very carefully push bullet to lands and grooves. Now with my left hand I gently push the bullet back just a little, with my right ring finger ever so slightly push the bullet forward until stops. I do this several times and then lock down the set screw. Remove unit and measure. Remember to keep pressure on the back of the case so it doesn't move. Works for me.

If you enjoyed reading about "30-06 maximum OAL" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!