FTR 308 155.5 or 185 juggs question

[Bryan Litz Ballistics]

Another important thing to note in this discussion;

The 'tight bore/groove' (.299/.3065) will make way more pressure with the 185 than the 155.5. If you want a barrel to run both 155.5 and 185's, it should be a standard (.300/.308) bore groove.

-Bryan

 

[Marksman63]

Noted. Thanks, Brian!

 

[Jefferson]

OK for us dummies or at least me,

with a .150 thou freebore what would the cartridge overall length for 185 juggs be, (I know they may vary with meplat differences), just trying to get a measurement for the gun I bought used,

does the freebore include the measurement known as the mean little shoulder


just doing some measuring at home and seeing the barrel for the 185's overall length the 185's may sit at, knowing there are huge differences in measuring and chambering

thanks

Jefferson (thanks XTR and Brian)

 

[savageshooter86]

measure a round for your chamber/bullet lot/brass lot/sized brass

Can either do this with a specific comparator or make a dummy round

 

[Marksman63]

Mine is around 2.940".

A question for the experts:
I requested chambering my barrel for the 185 Jug and didn't ask for a specific throat.
To get a rough of magnitude measurement of my throat, I used a round and measured difference between OAL and case lenght (2.940 - 2.005 = 0.935"). Then I subtracted the ogive lenght (0.793" from Berger sheet) getting 0,142".
Is 0.140" the right throat for the optimal 185 Jug round, meaning bullet seated with its tail's bottom in line with case shoulder's base?

 

[Jefferson]

mine was 2.943 on both guns so I am about 143 thou freebore , looks pretty coose as to what Brian was saying, I am just amazed at what took me a year to figure out to get the gunsmith to do up based on where the bullet should be and Brain just lets you know in 5 minutes on the computor,

with all that information up there how is there any room for any type of brains relating to pulling the trigger otr driving to the range

thanks again to all

I owe you coffee


Jefferson