3 blown primers out of 100??

[diego-ted]

I am backing down on my powder charge but am not sure how much I should cut back. I am very new to reloading, I am not sure what to attibute the blown primers too? I am just assuming it was pressure;however, when seating primiers I did notice a couple just went in without much pressure from the hand primer. Should I have just ditched those rounds? When two of the primers blew there was a semi-hard bolt open, when the last one blew it was a VERY hard bolt open with extactor marks on the case, enough to cause the extractor pin to get stuck with brass. What do you guys think?

thx Diego

 

[Kevlars]

Re: 3 blown primers out of 100??

What Cal. what brass what load and what powder and primer and bullet weight... that may help a bit.

Also what are you using to throw the powder? are you just throwing and loading or are you checking with a scale ever ... rounds.

Have you had any issues with factory rounds with the same bullet weight?

In general we need more information.

 

[diego-ted]

Re: 3 blown primers out of 100??

308, 168SMK, FGM case trimed to 1.983, 42.6gr H335. Fed 210 primer. Each load scaled. 10-20 thou from the lands. No problems with 168FMG

thx Diego

 

[jstevens]

Re: 3 blown primers out of 100??

The hard open, along with a blown primer says high pressure. The load is probably close to max., and if I were betting money the rifle was hot and the ones that blew sat in the chamber a while, letting the heat soak. It makes a lot of difference. Personally I'd load a slower powder than H335 in the 7.62, probably Varget or RL15.

 

[rudynix]

Re: 3 blown primers out of 100??

According to the Hodgdon's Reloading Data Center, you are .6 grains over max load.

 

[Greg Langelius *]

Re: 3 blown primers out of 100??

Too hot. The gun is telling you something that you must not ignore.

As a fairly experienced handloader, probably the best experience I can pass on to you is that we have all probably done our experimenting with hotter loads, and the lesson is simple. Nothing comes without a price, and the price for hot loading is most definitely too high to support any imagined benefit.

The bill always comes due.

What those who end up paying it find out the hard way is that once the loads have been shot, the clock starts ticking. When it rings may be with a hotter load, may be with a perfectly safe load. The problem is that the underlying metal fatigue damage has already been done, and that each overmax shot's worth of demage cuts another slice off the rifle's life expectancy.

Gun design specs generally include a safety margin that anticipates far, far more usage than any particular rifle is likely to experience. Unless you've really been twisting the dragon's tail with some considerable frequency, the odds favor a successful avoidance of any serious shortening of the rifle's reasonable life expectancy. Each rifle has a predictable life expectancy, and that expectancy is predicated upon using loads that meet safe pressure limits. Exceed those limits and all bets are off.

The time to stop hotloading is now. There is no safe margin for such things.

Greg