6.5x55 loading issue

[jimsbriar]

Hi all, I have a brand new sako finnlight 6.5x55 that I am reloading for. I found a great load with the 130 gr. bergers that was extremely accurate, but to get that, the bullet contact inside the neck was less than half the diameter of the bullet. even though the load was extremely accurate, I was nervous that the bullet might be disassemble on me (i.e. bullet loosen from neck from poor contact surface).

how much contact inside the neck is really needed?

In light of this I started working loads with the berger recommended seating depth and all my loads are no where near as accurate and I am getting "blow back" around the cartridge. see pic.

any idea what is causing this? poor pressure? headspace?

I have no signs of pressure in the primer and the fired cartridge ejects easily

the brass has been shot 2-3 times and only neck sized.

current specs: hornady brass, fed 210 primer, range of 45 gr to 45.8 gr of RE-19, 130 gr. VLD

 

[6.5x300]

Are you planning to use this load for hunting or just shooting off the bench? I would think if your just going to be shooting off the bench load it to give you the best accuracy and be happy with the accuracy. I don't think the small amount of barring surface would concern me that much if the accuracy is great.

Necks might be getting a little hard and if blow black is still a problem I'm sure annealing the necks would help.

Good shooting

BT

 

[jimsbriar]

thanks 6.5x300.

yup I want to set this up to be a 500-600 yard hunting rifle. One of the issues I am fighting, is that sako reams out their throats more in the 6.5x55 too accommodate the larger round nose 160 gr bullets. so, if your gun likes the bullets seating up against the lands, it leaves you with very little bearing surface contact inside the neck.

I am worried that if I drop one of these cartridges or just through the process of loading and unloading the gun at the end of a day of hunting, that I may inadvertently loosen the bullet from the case....

 

[benchracer]

First off, you are loading well below max with that bullet and powder combination. Nosler data shows a max of 47.5 g of RL-19 with a 130g bullet in a 6.5x55 at a COAL of 3.025. Given that you are most likely loading much longer than that and have a long throated chamber, I would not be surprised to find that your real world max is a couple of grains above what Nosler is showing. The low pressures your loads are producing are the reason for the blowback. I would also venture to say that you are getting poor accuracy because you have not yet reached the optimum pressure range for your powder. If the seating die you are using can be adjusted to provide a light crimp, it may help to do that.

I recommend working up in .5 grain increments to find your max, using virgin or once fired brass and watching carefully for pressure signs. When your fired loads stop smoking the case necks, that is a sign that you are developing enough pressure to expand the case neck and seal the chamber. At that point, you are starting to enter the working pressure range of the powder you are using. Keep working up carefully to find your max. Stop when you see pressure signs (such as shiny spots on the case head, ejector marks, or sticky bolt lift).

Treat the lowest powder charge at which you stop smoking the case neck as your starting charge. Treat the last powder charge BEFORE you start seeing pressure signs as your max. Using your starting charge, seat your bullet one caliber deep in the case neck. Treat that as your max overall length and work back from there following the Berger seating depth test instructions. Once you find your best seating depth, do your powder charge workup.