Gunsmithing help....

[18Echo]

During loading of initial rounds for a new to me .30-06 based off of an Eddystone I used my oal gauge to find measurement to OGIVE.

My measurements seemed very long... to long.

I took it to a well respected shop here in AZ and they checked headspace on it and said it was fine, the rifling looked almost new, and everything appeared to be cut very well. His advice was to load as long as I could and go shoot.

Brought it back to the house and wanted to double check my numbers.

Using Nosler 165 AB's OGIVE was 2.844 with an OAL of 3.470, thats .13 more than max OAL.

using Barnes TTSX 185's OGIVE is 2.843 again with an OAL of 3.474, .134 more than max OAL.

What does this mean if my headspace is good? What problems will i run into if I shoot this barrel? Do I need a new tube, or set this one back?

 

[GasLight]

Re: help....

headspace deals only with the case. The throat or lead is what gives you the OAL distance. If the headspace is good, I wouldn't worry about the OAL being above SAAMI max OAL. The throat could be eroded out, or it could have a long throat.

 

[doc76251]

Re: help....

First and foremost, headspace on a non rimmed cartridge is derived from the shoulder. So as long as your shoulder is in the correct place you can safely fire rounds.

Ogive is the point where the boolet will touch the lands.

The leade is where the chamber will contact the boolet.

The book OAL and Case Length have nothing to do with the ogive length.

That your chamber mics out long to the ogive point is a good thing. It means the rifling doesn't start where the brass ends. OAL has nothing to do with good barrel accuracy it has to do with magazine length.

Cheers,

Doc

 

[badbot]

Re: help....

load 220 round nose that should shorten the OAL

 

[18Echo]

Re: help....

Will jumping the bullet that far to the lands cause any accuracy problems, I know the Barnes are finicky about jump length?

I get that the Ogive has nothing to do with head space, I was just concerned that my bullets, if I wanted them touching the lands, would be past max OAL. I figured the max was "the max" for some safety reason.

 

[GasLight]

Re: help....

Max is a spec set by SAAMI for loaded ammo, so that it will work in any SAAMI spec chamber. There are guys having custom reamers and chambers done all the time. The only constraints on a round is based on your chamber, and your magazine if you want to load from a magazine. You typically want to have about the length of the bullet's diameter in the neck of the case so it has enough grip on the bullet, but that is a variable as well.

The lead or throat length can definately affect accuaracy, and you are going to have to play around with it to find out if there is hope for the barrel or not. I might try a box of match grade factory ammo first, and then go from there.