Thread: 6.5x55 accuracy

Greetings again,
There are two groups of causes for hang fires, primer problems and rifle problems. Primers can be old or have very hard cups as some military ammo intended for semi autos. We can't do much about these other than to avoid them. I would be interested to know if the round that hang fired was military, commercial or handload. The rifle problem is a weak firing pin strike. This can be caused by crud around the firing pin spring inside the bolt, a weak firing pin spring or the firing pin dragging on something like rust or excessive head space. The M38 Mauser is a cock on closing type with a long firing pin fall like the Lee Enfield. The spring can't be too strong otherwise it makes the action two hard to close. Some object to this and there is a kit to convert the rifles to cock on opening as mine has. The work to do this includes cutting a cocking ramp into the rear of the bolt. If this is not done properly a light firing pin strike and ignition problems can be the result.
Excessive head space is the result of setting the case shoulder back too far when full length resizing the case. For some reason (likely US arrogance) the US SAAMI headspace dimensions for the 6.5x55, 7x57 and likely others is significantly shorter than the European standards. There are two FL sixing dies in my collection. Both set the shoulder back far too far. For my M38 this amounts to 0.018" for the Redding dies and 0.022" for the Lyman rather than the desirable 0.002". Hornady sell an inexpensive head space comparator that clamps to the lower jaw of your callipers that is a great help in setting up the die not to set the shoulders back, Excess headspace can result in miss and hang fires by softening the firing pin fall and I wouldn't be surprised to find that is the problem here.
Regards Grandpamac.