Chamber dimensions of Savage factory F class rifle

[Tozguy]

Just wondering how my measurements of a new Savage F class in 6BR compare to yours. The overall all length is 1.577'' and the neck is .271'' according to my method.
Loaded no turn Lapua brass with 105 gr. Scenar is .269''. I plan on using a Forster .268'' bushing to reload these puppies. What do you think?

 

[zullo74]

Good to Go.

 

[deadlyswift]

I was just wondering if you are mesuring the neck of the case after it has been fire in your chamber? If so you probably have a .272 neck and the brass is springing back to .271.
Good luck to you and your 6br. Hopefully I will not have a mental break down waiting on my 6br to be put together and the stock clear coated! I'm chompping at the bit to start shooting it!

 

[fdshuster]

tozguy: Everything sounds good. They gave you a chamber length of .017" longer than max case length. I've measured factory chamber lengths that are as much as .035"/.040" longer. Also sounds like a .272" chamber neck, with the springback to .271" as fired. Using a .268" bushing means the brass is being worked a maximum of .004". My Lapua is giving me up to 30 reloadings with the same dimensions you have, then I start to see the wrinkles beginning, a split soon to follow. But I stop using the brass when the wrinkles first appear.

 

[Tozguy]

Deadly, the chamber neck was measured with a brass rod rod gradually turned down until it was a snug fit in the chamber neck. Haven't fired the rifle yet, need to get a longer cleaning rod.
Thanks for the feedback folks, much appreciate it.

 

[RonAKA]

I am looking at a similar situation. I have no first hand experience, so take this as a comment/question rather than any criticism.

When I read the Forster Neck Bushing and Bump Die instructions, I see they recommend you measure several loaded cartridges, and then take 0.002" off the minimum sized case that you have measured. I've read that new Lapua brass tends to measure 0.2685 to 0.269". So using those numbers the appropriate bushing size would be 0.2665". Since they don't come in half thou increments I guess you would either go to 0.266 for a bit more tension or 0.267 for a bit less.

http://www.forsterproducts.com/client_images/catalog19938/pages/files/Bushing_Bump_Neck_Sizing_Die_DIE-0008.pdf


If you go with a 0.268 bushing, will the brass not spring back to about 0.269" OD before loading. Then if you only have 0.269 after loading, then there would seem to be zero tension. Just thinking out loud. Perhaps I am missing something here.

 

[deadlyswift]

RonAKA,
It will depend on the neck Dia. of your chamber as to what your brass will spring back to. If your chamber is .272 neck your brass will spring back to .271. Now I will take a stab at this but I can't promise you I'm exactly right. Some of the more experience may correct me. My new Laupa brass and loaded dummy round is .266 upon the first firing of my virgin brass the brass will expand out to .272 then spring back to .271 I have now a .268, .267, and .266 bushing. I don't know which will work best, but I found with my .308 that I had to expermint with bushings to find the correct tension. I have been told from an ACE Member on this site that the .267 bushing will most likely be my bushing of chocie for the 95gr vld berger. The .267 bushing should give me a loaded round of .269, this giving me .003 clearance in my chamber of the loaded round. I have also found when working with my .308 that I use different bushing for different bullets. Example my chamber has a .342 neck, or I believe it to be my fired brass comes out at .341 it is a factory barrel. I have found that the 175gr. bergers shoot better with a .336 bushing, but the 175 SMKs shoot better when using a .337 bushing. I'm not sure as to why this is? I am still learning myself. Before I was using the bushing mentioned above I was getting a lot of vertical with both bullets. Once I found what bushing each bullet wanted the vertical went away. My groups now only have horizontal due to misreading the wind or due to the Nut behind the Butt! Anyway I hope this helps. If not I'm sure some of the good Experinced guys will come along and better explain it. There are some very experienced shooters on this site! Hopefuly one day I can be one of them ;D
Mark

 

[RonAKA]

I think one of the other issues at play is the actual diameter of the bullets used. While they are a nominal 0.243", the actual dimension may vary. If the bullet diameters vary, and you want the neck tension to stay the same, you may have to use different neck sizing bushings. See this information on Bart's 6mm bullets and how they change in diameter.

http://www.bartsbullets.com/products/barts.html#6mm