Thread: Head Space Struggles with the 6.5x55.

Greeting All,
The 6.5x55 has been a long time favourite of mine and over time two have found their way into my gun cupboard. For a long time I neck sized most cases for my rifles but more recently I have fallen under the spell of the Hornady head space comparator kit and the Redding competition shell holder sets. All went swimmingly until I got to the 6.5x55 rifles.
Starting with the T3 a fired case and the plus 0.010" shell holder and Redding dies sized cases chambered with ease. That wasn't supposed to happen. Measurements with the comparator showed that the shoulder had been set back 0.05mm (0.002") about right. The chamber on my M38 is about 0.1mm longer than my T3 so for them the shoulder would be set back 0.15mm (0.006") and this was with the +0.010" shell holder.
I knew that my old Lyman dies sized the cases even more so out they came for some measuring. Turns out they set the shoulder back 0.2mm further than the Redding.
But wait, there is more. The old Lyman dies and a RCBS neck dies size the neck of my Lapua and Norma brass nicely but with Winchester brass barely touches the neck so a projectile drops right through. With the Redding die the Winchester brass is fine but the necks of the others are overworked.
Bother.
So how did this shambles come to be. Well it appears that when SAAMI set the standard dimensions for the 6.5x55 and many other non US cartridges they failed to follow the overseas standards. There is an arrogance in the US about anything not invented in the US being any good. Unfired Lapua cases in the T3 chamber are a perfect fit so the problem is not there.
So now I must work around the problem created in the US. The T3 is a hunting rifle so the oversizing of the necks can be tolerated for the limited number of rounds likely to be fired so the Redding die with the +0.010" shell holder will be used. For the M38 the Lyman FL die will be set and locked to give the right headspace. The RCBS neck die would be an option for light loads as well.
All this filled in some rainy days so all is not lost.
Regards Grandpamac.