30-06 Reloading - OACL

[Irish Gunner]

I plan to reload 30-06 rounds for the first with various charges / bullets to see what my Rem 700 likes. First I thought I would take a close look at 4 different factory loads (dimensions etc) and see if any shoot well.

I was surprised by the spread in cartridge dimensions. I had Greek Surplus Garand with OACL 3.32 vs. Rem 150 gr Core-Lokt SP at 3.18. (Nosler guide says 3.34 max. The best shooting group was with 168-gr Horaday A-max Garand "match" and the OACL was 3.25. The Remington was the worst.

So my plan is to load up Hornady 155 gr A-Max and Nosler 175 gr custom comp BTHP over Varget and IMR4064 and aim for OACL of 3.30-3.32. How much wiggle room is there with OACL? Is the base to ogive a better dimension to monitor? Anything else to look at?

My goal is to find the best fit for this rifle and then take a precision rifle course with it.

[Fjold]

They have different OALs because the bullets have different ogives. Absolutely the best way to measure is ogive length.

[Irish Gunner]

They have different OALs because the bullets have different ogives. Absolutely the best way to measure is ogive length.

In my limited sample the base to ogive (BTO) was all over the place too. 2.49 (Remington) to 2.76 (CMP). I know that I need to find the BTO that minimizes "jump" to increase accuracy.

Lets say that the best BTO puts the OACL beyond the SAAMI max OACL of 3.34, is that an unsafe situation? I would think OACL would matter more for magazine fed rifle than a bolt, but I have no experience here.

[Witch Hunter]

First, you are limited to magazine length unless you want a single shot. To find your max COL with any bullet, use a sharpie to mark the bullet, load it very long in a dummy round and chamber it. Look for rifling marks on it. Adjust your seater die to just where you cannot see marks. This is your max. I start about .020 shorter than that. You will have to repeat for every different bullet

[BLR81]

even the same bullet from the same manufacturer will vary from one batch to the next and sometimes among boxes from the same batch.

I load 30-06 with Imr 4064 and Nosler 168 comp. and, set COAL to .030" short of the lands. There are many ways of measure the length to lands, I use a 1/4 dole rod and insert it into the muzzle with the bolt closed and no cartridge. Then I load a cartridge with the bullet I want to use so long that I can't lock the bolt.

I then hold the bolt against the cartridge, and insert the rod again until it hits the nose of the bullet. the nose should be touching the lands. Mark the rod again, and the distance between the marks should be equal to the distance from the bolt face to the lands.

load a dummy cartridge .030" shorter than that length, and check that the bolt goes into battery. Use that length to test your loads. After you come up with a powder weight that works with that bullet at that length, you can always go back an retest in .005" longer increments. checking for pressure signs before seating any deeper.

My COAL for a 1903-A3 is 3.360 but I load to 3.345. But, that is not saying that that length is safe for your Rem 700. Newer factory rifles have a much different tolerance than a rifle made to be dragged thru a war and still fire.

the rule of thumb (hate those) is the bullet should at least be seated to a depth equal or more than it's caliber. 30 Caliber should be seated a minimum of 0.300" into the neck. The danger of loading too short is as serious as loading too long. So, measure what's best for your rifle.

[milotrain]

There is likely not a .30 cal bullet you would want to afford that will have a problem jumping. Load them to fit the mag and shoot them. If they don't shoot well enough for you then start jamming into the lands with reduced powder charges. Don't shoot VLDs there isn't any reason to do so with Berger's excellent hybrids and Hornady's A-Max range.

[Irish Gunner]

Thank you all for the advice. I will be looking to determine the bolt to lands distance with the dowel rod shortly. I was thinking of getting the Hornady OAL guages (and still might), but this seems to be a cheaper and quicker method in the mean time.

The variability of factory ammo, and my scientific nature are the two reasons I am starting to load my own. I will test my powders using an OAL that is 0.30 off the lands. Once I find a good one, I will vary OAL from 0.2 to 0.4. That should give me a good sample.

The longest I have ever shot is 200 yds. I want to find a sub MOA recipe so that I can feel comfortable out to 600 yds or so.

[milotrain]

To 600 yards the 190 SMK will do everything you ever want for not a lot of money. Hornady's A-Max 178gr will do very good for pretty cheap. The Berger 185gr Hybrids are also good but quite expensive.

You can save some money by running the 155gr SMK (hornady, or Nosler CC) to 400 yards and the heavier bullets out to 600.

Read this:

http://riflemansjournal.blogspot.com/p/articles-index.html

[6mmintl]

If you going for precision or longer range shooting seat the bullets out to just touch the rifling (long on remingtons) for best accuracy.

You single load in most precision/long range discipline's so seating to mag length is not required.

[mark501w]

Set to mag length if you want a repeater,if your going to single load build a dummy rd set bullet long ,chamber ,set die add one turn on bullet seater check for additionall lands &groove marks if none use dummy rd in future.

[Irish Gunner]

I tried to determine the distance from bolt face to lands with my 155 gr Amax bullets, but I couldn't load a dummy long enough (using dowel rod method). Anything beyond about 3.5" and the bullet isn't seated well and the round still chambers. I am going to seat to 3.45" and see what happens this weekend.