6 dasher, tight chamber?

[lennyo3034]

I have a shilen Lapua dasher prefit barrel and I am running trimmed Norma Dasher brass.

The bolt closes with light resistance on a go gauge.

However actual rounds close with significant resistance. This occurs with and without a projectile loaded. I've been told the base of Norma dasher brass can be a bit thick and is what is causing this. Or is my headspace just set a little too short?

 

[CaptainMal]

Could be all three things you mentioned and maybe more.

The Norma brass does need a longer chamber neck length for that . Shorten the neck of the brass a bit more to be sure that is not the issue.

On the headspace issue, measure a case, set your dies and make it couple thousandths less to see.

On the head size as the first generation Norma brass was thicker, file one smaller and see if that works.

Then, for a fourth idea, was the chamber made to take a non-turned thick neck. That brass in thence is probably .013" thick or more. What is the neck diameter of the chamber? Try squeezing down the neck diameter of that case you should be playing with and see if a small diameter necekd case fits in.

The solution is easy if you have the reloading skills to take it one step at a time. If not, maybe someone around you can offer some help.

 

[swd]

Sharpie a case in a few strategic places, clean and dry the chamber and see where it's tight. First run Norma Dasher brass have thick rims in the linear dimension but are slightly smaller across the .200". My guess would be headspace or the necks are still too long or the necks need to be turned.

 

[DaveTooley]

Virgin brass or fired brass? Another possibility that I see happen from time to time on virgin brass is mismatched radius at the neck and shoulder junction. Mark with a sharpie then look and see if you get a ring on the brass after inserting it in the chamber. It will go away on firing.