Help with .30-06 O.A.L

C

Carl_.30-06

Inactive
Like a lot of these probably start… I’m new to reloading. I am starting with .30-06 and plan to expand to other calibers after I get more comfortable and familiar with the process. Here are the components I have:

165 gr. Hornady SST
Hodgdon H4350
Win Brass
Win LR Primers

I loaded up 10 with 57.0 gr. Of H4350 and an O.A.L of approximately 3.245”. I was impressed with the accuracy of these over factory loads. I expected it to be better and I wasn’t let down. I think I consulted several books in Cabelas and various forums before coming up with this load. The length was dictated by the cannelure on the SST which now know is not so important for bullet seating. I would now like to begin the work of optimizing to best suite my rifle. I loaded up 6 @ 56.0 gr., 6 @ 57.0, 6 @ 57.5, and 6 @ 58.0 gr with the same O.A.L of approximately 3.245”. The plan was then to start playing with the length after I get the right load. I’m not sure it this is the right approach but it was my plan.

Here is the question- I am starting to get a little nervous about my O.A.L of 3.245” after seeing 3.330” listed in several books, especially with the 58.0 gr. loads. Do any experienced reloaders see this as an issue? I will probably back out the length after I shoot these and get the best charge to get the bullet closer to the lands. I’m not really looking for match accuracy, just general-purpose hunting accuracy. Any words of advice on finding the right O.A.L would be appreciated. Thanks in advance.
 
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Something is being lost in translation... a 30-06 case is longer than 2.245". It's physically impossible to load a round that short.... do you mean 3.245?
 
What tool are you using to measure these cartridges?
If you are using a Comparator, and zeroing it, that's where you're coming up with a short measurement...
COAL is and acronym for cartridge overall length and is from case head to tip of bullet.
CBTO is a measurement from case head to ojive, and zeroing a Comparator after its attached will gather short measurements..
 
I am just using a caliper measuring the total length of the completed cartridge. That is the measurement I am referring to when referencing O.A.L.
 
my 30-06 is built on a sporterized mauser so rounds pretty much have to feed from the mag. I can load to 3.375" OAL before bullet tips start touching the front of the mag well. This OAL does not put the bullets at that "magical" point but it shoots good enough for me.
 
Ok, good.


Anyhow, now that we're on the same page, you can rest easy knowing that making a rifle cartridge shorter generally DECREASES pressure until it is so short as to significantly intrude on the powder burn space.

Our own UncleNick has often posted this graph showing the effect, conveniently even in a 30-06:

seatingdepthvpressure.gif


Note that the measurement is distance from the lands, that is, how far the bullet is from touching the rifling. In OAL terms, the cartridge is getting shorter from left (longest) to right (shortest).

No way to know this (distance from rifling) in your gun without measuring, there's a tool for that.

It's unlikely that your 3.245 is more than 0.250" (1/4") from the rifling and so being "shorter" is making your pressure lower rather than higher.

Now, I recommend you get that tool. There are other ways of finding your rifling but none (including the tool) are terribly reliable without practice. The tool just makes it all easier.

You can also tape a bullet to the end of a wooden dowel, remove the bolt from your gun, carefully slide the dowel into chamber until you feel the bullet contact the rifling, slide another dowel down the muzzle, mark that one at the muzzle, remove the bullet/dowel, reinsert the bolt, slide the dowel further into the barrel and remark it. The two marks will be the max OAL of your cartridge with the bullet touching the rifling. Most folks start 0.050 or so shorter but there's no magic number.

Other folks do the same basic job by sizing a case and then cutting a length-wise slit in the neck (with a dremel or similar) so it holds the bullet but still allows it to slide somewhat easily. Then seat the bullet very long, insert the cartridge in the gun, *gently* close the bolt and *very gently* open it. The bullet *should* be pushed back into the case by the rifling and give you the same measurement as the wooden dowel method.

In reality, all 3 methods require practice to get right and can make for inconsistent results. All of them can also be accurate, when you get used to them and makes the tweaks you need for your situation.

Also note that with a bullet as light as 165gr in 30-06, you may not even be able to reach the rifling in an assembled cartridge. That is, your calculated length to touch the rifling will be longer than the bullet and case put together.
 
Hornady's 9th Edition Manual lists the recommended overall length for the 165 SST in 30-06 at 3.210". You already are .035" longer than Hornady recommended. I'm fairly sure you're getting within about .020" from the bullet contacting the rifling if your rifle is a standard bolt action. It would be nice and also a safety factor to KNOW how long you can seat your 165 SST bullets to just touch the rifling. Also feel that loading to your 3.330" number and the round will not chamber and the bolt won't close. Find a method to check how long you can seat to touch the rifling. For hunting rounds keep the bullets back at least .010" from touching. Bullets touching or jammed into the rifling increases pressure and sometimes to dangerous levels. Bullets touching or jammed require a reduction in powder charges. I've experimented with bullet seating depths with Hornady jacketed bullets and starting .050" from touching the rifling and go in .010" at a time stopping at .010" from touching. In my rifles I've used this method I seem to get best accuracy at about .030" from touching. Your rifle and loads may differ.
 
You need to learn SOoo Much More...

I'm reading between the lines here, but from the things you say and the questions you ask in the OP, it seems that you are heading down a dangerous path. You should not have started reloading without learning so much more about the process.

It sounds like you did nothing more than compare the load data in a number of books you do not even own before you started putting things together. If that is accurate, then bad, bad, bad. Had you actually sat down and thoroughly read the TEXT in a manual like Lee or Lyman (that is the information BEFORE the part where the load data starts, and ALL of it), then you would already have the answers to your questions. And you would be a much safer reloader.

I am not trying to insult you or put you down, just trying to advise a new reloader to be more cautious about things you do not know that you do not know. Best to back up and learn more before doing more.
 
I think I would find the recommended OAL for the bullet I chose in the bullet manufacturer's reloading manual (Hornady bullets = Hornady manual). I would then develop a load that works well with that OAL, then try different seating depths (there are several methods to measure the length from the bolt face to beginning of the rifling). I've found it's best to work up a load by changing only one item/component at a time...
 
"...I loaded up 6 @..." You need to begin at the starting load and go up by half a grain to the max load. Load a mag full or 5 of each(depends on your rifle) then go shooting, for group only, at 100 yards, off a solid bench rest.
"...O.A.L of approximately 3.245”...." There is no 'approximately'.
"...length was dictated by the cannelure..." Forget the cannelure and seat to the OAL given in your manual.
"...my O.A.L of 3.245” after seeing 3.330”..." Relax, neither is quite right, but not unsafe either. Been using the MAX OAL of 3.340" from my old Lyman book, with ALL bullet weights(mostly 150's and 168's), for 40 years. Using an M1 Rifle and a 1903A4. Never had any issues.
"...how far the bullet is from touching the rifling..." Is a load tweaking technique you do not need to worry about or bother with until you have a load. The distance from the rifling is different in every single rifle. There is NO absolutely exact number for it.
 
Tim, where do you get this stuff, he needs to begin at starting load and work in .5 grain to max load...
First of all he should start at the min, however if the manual shows 2 grain increments then they already ruled out any relevance of .5 grn increments.
And 6 rounds is better than 5, for two reasons: 1.relevance and consistancy.2. Familiarization of his rifle and shooting skills.
And the cane lure remark, dude I load and test at least 20 different bullets of multiple calibers, and only 1 has a canelure, only one...which doesn't make a dang bit of difference in my seating depth sweet spot....
 
To Carl-30.06 RE:oal

Hi
There's a great book out by Berger Bullets. Edition number One. They go into OAL variations at length, and it's much more info than anyone can give you on line. The book, I believe, is about $25.00 on Amazon, plus it gives loads for most Berger bullets(the only one that they didn't have was for the .338 Win Mag, which I got on line). I've been using different OAL's on my .338 win mag and .300 win mag, and it certainly makes a difference. There is no one length, because, as you will find out, each gun has a personality of it's own.
Good luck, and have a Merry Christmas and Safe shooting new year.
Mickey
 
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