Bullet seating depth question.

[alpha1]

The caliber is 6.5x55 to be able to chamber the rounds from the magazine using 139 grain bullets they have to be seated to a over all length of 2.898. If I build them longer they wont go over the feed ramp and jam in the magazine. If I single load them I can seat them longer I am using Vitavouri powder. Vitavouri load data quotes a cartridge over all length of 3.150 for this weight of bullet.

 

Am I OK to seat the bullets to magazine length.

 

Some back ground information the rifle is chambered in 6.5x55. The action is a short .308 action. The barrel is a shilen 6.5x55.

Why it was built on a short action I have no idea. But it shoots Ok but its a pain in the butt to reload for.

[gbal]

COAL is a critical measure as you note,but for magazine feed mainly,because:

 

Bullets vary in 'length' and ogive-the bit that can contact the rifling-and that is well short of the bullet tip( see below).

 

Generally bullets are seated just short of their ogive touching the rifling..variably,but say 10 -15 thou.

 

Bullets seated into the rifling may increase pressure.And might just jam/spill powder if unloaded live-single feed does not avoid this -the bullet is still " jammed' into rifling to some extent.

 

Bullets compressing the powder charge when seated will change pressure-a 'compressed load' (how much/case capacity differences?)

 

You could try different suitable bullets-the CBTO (cartridge base to ogive) will vary(as well as COAL).

 

You could reduce the powder charge- it's unlikely to make the cartridge less field effective -if 1800 ft lbs don't work at 200y,it's unlikely 1900 ft lb will. Assuming it still 'shoots OK' -max charge is seldom the most accurate one.

 

The short action does however potentially compromise bullet choice/seating depth-though different throating length etc can mitigate this-we don't know if yours is custom throated to help here....but the Shilen is not a factory barrel,so maybe...?

 

BUt there are some options,and 'different compromises'- with some 'acceptable' ones,if you can be a little flexible-while preserving terminal performance.

 

Deliberately general above-others may have specific suggestions based on shooting experience-but throating may differ,and therefore applicability in your rifle. Good luck.

 

Gbal

[duey]

Your problem is exactly why the 6.5 x 55 is built on a longer action

You can not work with published data for your round as they won't be relevant if you wish to use the magazine

 

If you can/want to single feed sammi spec rounds then by alll means use the published data otherwise you will just have to work up from minimum loads and see how you go