Size problem, what to adjust?

[Razor18]

Hi There,

I use munition reloaded by my friend to my .30-06 Tikka, and more times than not, it is a bit difficult to close the bolt on some of the cartridges, but there is no scratchmark on the bullet, so it's probably not bullet seating depth. What does he need to check next time when reloading?


THanx!

 

[Rich Coyle]

He needs to have the rifle at hand when he sets the full length die. The die should be set so even the case with the most spring back easily goes into the chamber. But closing the bolt should give a little resistance if he puts a piece of paper on the bottom of the sized case or bot face when trying to close the bolt.

When he sets up the seating die he needs to make sure the cases are not bottoming out in the chamber because the neck is too long. Once he has established this he needs to set the seater about a half turn above the length of the empty case. Also he needs to make sure the seated bullet is not touching the lands. Any clearance is better than touching.

 

[bigedp51]

Buy a Hornady cartridge case headspace gauge, then measure a fired case and then adjust the die until you have .001 to .002 shoulder bump or setback. (bolt action-.001 to .002 semi auto .003 to .006)

Below a fired unresized case fired in my AR15.

Below the same case after full length sizing and .003 shoulder bump.

With the above Hornady gauge it takes all the guesswork out of sizing your cases to the proper shoulder to base length.

Below an exaggerated sizing illustration, for a custom fit adjust the die to push the shoulder back a few thousandths below the red dotted line.

 

[bob4]

If he's using his own dies for this you may consider buying your own. This way once your dies are set up for that rifle they will build your ammo for your gun and he doesn't have to make major changes to his dies.

 

[Trickymissfit]

everybody has their own way. Here's what I do, and take it from there:

* I take three once fired cases that are fresh out of the rifle, and have had nothing done to them. Wipe them down with four ought steel wool. Wipe the case head on a fine stone to make sure the extractor hasn't bent the rim. From there I'm good to go as I now have a case that mirrors my chamber. I then measure the case with a Stoney Point headspace gauge (now sold by Hornaday). I do this to all three cases, and then set the die up to push the shoulder back on the shortest case .003". How does the bolt fell when closing? I like a slight bit of resistance just as the bolt is completely closed (maybe the last quarter inch of travel in the bolt handle). Still a little too tight? Then take .002" off the shoulder distance. If you get to .007", I'd be checking the chamber neck length. Not common, but have seen a couple that were only .015" longer than the case (my 6/250AI is that way). Of course I've seen a few that were around .070" too long. I would also measure each case three or four times and recording the numbers.
gary

 

[Sully2]

Hi There,

I use munition reloaded by my friend to my .30-06 Tikka, and more times than not, it is a bit difficult to close the bolt on some of the cartridges, but there is no scratchmark on the bullet, so it's probably not bullet seating depth. What does he need to check next time when reloading?


THanx!

The shoulder needs set back a small amount. Buy your own dies and have your partner use THOSE adjusted for your rifle.

 

[Razor18]

Thanks for all the replies!

Can anyone tell me the diameter of a Hornady (or other) bullet comparator for caliber .30 please? I want to measure the head-to-ogive distance...

Thanks

 

[bob4]

 

[Razor18]

Hi Bob,

thanks for the picture, but this in fact does not answer my question. My question was what is the inside diameter of this insert (the diameter that touches the bullet while measuring). I know this insert is for .30 cal, I know .30 cal has a diameter of .308., and this insert has an ID of 8-30. But what is the actual inside diameter?

 

[dok7mm]

It will vary slightly from comparators within one brand and of course from brand to brand. That is why it is so important to use the same comparator on your individual setup.Always use exact same bullet when setting up your CBTO length. Repeat procedure with each bullet style you use. The internal diameter is not critical if you use same comparator set-up each time and keep good notes. Set up a dummy round when you settle on preferred CBTO.

 

[Razor18]

I knew all that too, but thanks... I just want to make my own comparator for .30-06. For that I need a diameter to be in the ballpark. Just a number...

 

[Razor18]

Well, interesting thing happened. I had a measuring gauge made based on the SAAMI dimensions of a .30-06, which says case size is OK, if the distance from the bottom of the cartridge to the reference diameter of 0.375" on the shoulder is between 2.0487" and 2.0587".

Before having this gauge made, I also ordered a Lyman headspace gauge, where the difference between the GO and NOGO size is about 0.006" (measured with caliper).

After recieving the measuring gauges I checked the actual size of my reloaded cases, they were all between 2.0487" and 2.0587" alright, but checking them with the Lyman, every one of them seemed to be about 0.006" too long, being all NOGO! But if this would be true, I wouldn't be able to close the bolt on my Tikka, but it closes easily, without any resistance.

I really don't get it: can the Lyman factory gauge be wrong??