Chamber length question**update in OP**

[18Echo]

I recently came into a custom hunting rig in .30-06. I started working up some loads today for 165 Nosler Accubonds with Varget and IMR 4064.

I didn't have a modified case for my OAL gauge so I loaded a bullet REALLY long and then chambered it. Total length was 3.427. With a Max COAL of 3.340 this means I'm jumping .087 if I load to max length.

Does this seem like a long jump? I load my .308 in a GAP to jump .020 to the lands, so .087 seems like a huge distance. Thoughts?

UPDATE:
Got a modified case today and measured 8 times. Distance to lands is 2.848 from the Ogive and a Coal of 3.475, thats a .065 jump.

And the guy I bought it from 2 weeks ago said that he took it to a shop to have a muzzle break put on it and they wouldn't work on it because it didn't headspace right.

 

[vinconco]

Re: Chamber length question

Depending on the leade taper it is possible to jamb a bullet quite a distance into the lands using the gauge and modified case. Using the Stoney Point gauge with the modified case it is possible to get a variation of +-.015" or more depending on how much pressure you put on the bullet. Using a unmodified case with standard neck tension I'm sure it would jamb into the lands a lot so you're probably not getting a accurate reading.

 

[Hummer]

Re: Chamber length question

Yep sounds like your modified OAL set up needs modification some more. At that length you won't get it to feed from mag but if you are single shot loading no problem.
You probably should be able to grasp the bullet and pull it in and out. Most likely you should see land marks on the bullet you used.

You might try using a different bullet that is unmarked after you loosen the neck tension on your trial case.

Some barrels will allow a bullet to take a long jump and others will not

Then there may be enough meat on the barrel to have it set back a set of threads which should bring you into almost new lands.

If you are thinking of that or a new barrel you might consider getting your own chamber reamer that will cut chamber min dimensions to a lot longer brass life down the road. With the cost of brass these days you can buy a reamer and pay for it in a year of shooting.

The way I order new reamers is to take a box of new factory ammo. Measure the bases .200" up from rim. On 30.06 this should be .465" on commercial and military if rounds are new. My reamers cut .467" and .469" on base. Standard reamers will cut .471" to .473".
Next I measure the neck dimension and add .002". Finally I headspace to snug on a GO GAGE.

Set up like this your shoulder will barely move, the base will expand minimally as well as the neck and on LC cases you should get about a hundred reloads.