Chamber Specs with Freebore for 7mm-08 & 162 ELD-M

[AROKHUNTER]

Can you guys, and gals, help me out here. I’m trying to get an idea for the Freebore measurement using the 162 ELD-M in a magazine fed bolt action.

If possible, please post your Freebore and the COAL along with the jump measurement to the lands.

Hypothetically speaking, let’s say a chamber has a 0.055” Freebore with the COAL at 2.800”.

So, if I can load to a COAL of 2.900”, would the Freebore simply move forward the same amount as the difference in the COAL, which would be 0.100” ??? Making the Freebore 0.155” for the COAL of 2.900”.

Am I thinking right?

 

[284winner]

Short answer is yes. Freebore is the measurement from the ogive on the bullet to the lands in a rifle barrel. That means every (different style)bullet will have a different measurement to the lands when seated the same depth in the cartridge. Even tho the freebore is set when chambering, the measurement changes with different bullets. IMO, making dummy rounds for your gunsmith is the best way to set up the freebore.

 

[AROKHUNTER]

Short answer is yes. Freebore is the measurement from the ogive on the bullet to the lands in a rifle barrel. That means every (different style)bullet will have a different measurement to the lands when seated the same depth in the cartridge. Even tho the freebore is set when chambering, the measurement changes with different bullets. IMO, making dummy rounds for your gunsmith is the best way to set up the freebore.

Thanks. I plan on making some dummy rounds. I was just hoping I could get some information from shooters with the info that I mentioned so that I might have a general idea of what to expect as far as maximum COAL for a given Freebore measurement.

I’m only home 2 days a week, so the info here helps me get a jump on things. Lol.

 

[Dusty Stevens]

send dummy rounds to JGS and have them make a reamer to match. be sure to seat them a little deep to give some wiggle room. that big of a bullet in that small of a case will cut down on case capacity at mag length

 

[Bart B.]

Short answer is yes. Freebore is the measurement from the ogive on the bullet to the lands in a rifle barrel. That means every (different style)bullet will have a different measurement to the lands when seated the same depth in the cartridge. Even tho the freebore is set when chambering, the measurement changes with different bullets. IMO, making dummy rounds for your gunsmith is the best way to set up the freebore.

Free bore is the cylindrical length of bore in a firearm just forward of the chamber neck in which rifling is not present. It's the part of the bore that's free of rifling. It is part of the barrel chamber, has a fixed length and therefore does not change with ammo variables. For some chambers, it is zero length as the angled rifling throat (leade) starts at the chamber mouth.

Are you thinking about something else; bullet jump distance controlled by bullet seating amounts?

 

[284winner]

Free bore is the cylindrical length of bore in a firearm just forward of the chamber neck in which rifling is not present. It's the part of the bore that's free of rifling. It is part of the barrel chamber, has a fixed length and therefore does not change with ammo variables. For some chambers, it is zero length as the angled rifling throat (leade) starts at the chamber mouth.

Are you thinking about something else; bullet jump distance controlled by bullet seating amounts?

Yes that's pretty much what I defined it as. No it doesn't change no matter what ammo you use. What does change it the measurement to the ogive from the rifling on the various bullets used. The freebore length only changes when erosion begins. Either way, my definition pretty much is the same as yours with different rhetoric.

 

[jsthntn247]

You really need a long action to get the most out of it.

 

[284winner]

You really need a long action to get the most out of it.

I'm not 100% sure but with the 162s, even with a 2.950 OAL, you should get the most from your case. Anything longer than the 162 would certainly benefit from a long action.

 

[AROKHUNTER]

Does anyone know about how much lead growth to expect with the 7mm-08? Is it about .002” per 100 rounds, or .005” per 100 rounds. What should I plan on? I want to leave enough room to chase the lands when I need too.