[JTknives]

well today i went to the range and tested out some worked up loads. thy where irm 800-x, AA#7 and Blue Dot. The 2 that seamed to give me the best group size was these listed below. I don't consider my self a good shot so be kind.

Glock 20SF LW threaded barrel with Comp
10.00gr AA#7 180gr FN plated CCI 350- spread max was 1.35" @ 7yd
10.50gr BlueDot 180gr FN plated CCI 350- spread max was 1.13 @ 7yd

so these made me happy as i was able to track spread pattern as the loads increased. but what i was really excited about testing where the 135gr IMR 800-x Loads. I had 5 0f each step starting at 12gr and going up to 14gr. i loaded up 2 of the 12gr and pulled the trigger, nice. I looked for the brass but its gone. so i fired the last one in the gun and snagged the case. the case looks good, the largest dimension on the case is .428 so i checked out the primer. and what to my surprise do i behold, a flat primer. i have heard about them but have never got one. not its not so flat that it blends in the the case but the rounded edge of the primer is gone. I was not expecting flat primers from only 12gr as the listed mag is 14.5. i know that max is high and has since been pulled but come on flat primers at 12gr. These have a crimp similar to DTs crimp. what I'm wondering is can i trust the primer as a good pressure test or should i shoot the rest of the 12gr loads and see if any more flat primers pop up. also another thing is that this is starling brass i though it was new but it might be once fired as i can now remember. but the words on the rim of the case seam to be a little less deep and the bottom of the case has the same texture on it as the primer. it looks like the texture on the breach face pressed into it. Thanks and i hope someone can help. thanks so much

[JTknives]

Does no one have any good advice :(

[AJE]

How about a picture?

[JTknives]

ya my bad, that would be helpful. here is a few pictures. man it was tricky getting a clear shot.

[hill billy]

Those aren't bad at all. The one on the lower end of the left picture is starting to get flat but the others are fine.

[JTknives]

Originally Posted by hill billy

Those aren't bad at all. The one on the lower end of the left picture is starting to get flat but the others are fine.

ya that's the one i was worried about

[Taterhead]

Are you hand weighing the 800-X loads? If not, 800-X meters poorly and it is quite easy to get widely varying charge weights. The reason that I ask is because the one at 7:00 has a different result than the other - it would pique my attention too. Another possibility is that you had a high primer that backed out a bit and then was smashed back into the pocket. However, as you mentioned before, it looks as if the breach face is "printing" on the case head. Again, my attention is perking up.

In my experience, 800-X and CCI 350s get pretty flat at relatively modest charge weights. Others have noted similar results. I've had better results with standard primers. Of course, the velocity spreads open up with standard primers. In general, I have had poor results with projectiles weighing 180 gr and higher with 800-X. I posted about this a few months ago, but I noticed severe signs of excess pressure with 800-X under a 180 gr XTP. That was at a charge more than a full grain below the max charge.

Others will jump in with completely contradictory results. That is why we all practice good handloading procedures - results vary.

In general, primer condition is not a reliable indicator of safe pressures. Case expansion is a better indicator. You have mixed brass here, so there may be variations in max case expansion. For load development, I use brass of similar makes to eliminate, as much as possible, the differences in metallurgy. Ken Waters has a method worth considering that uses a sophisticated scheme of case measurement to gauge pressure levels. Understanding his methods will give more information than observing primer conditions. Make sure that if you have not done so already, you read MakeMineA10MM's comments here:

http://www.glocktalk.com/forums/showthread.php?t=179485

[JTknives]

the case on the bottom is the only one that had the 135gr nos with 800-x. the one is a double taps as you can see and the one on the top left is on i loaded with 180gr plated and 800-x and a mag primer. these rounds work good but its just that 135gr nos with the mag primer and 12gr of 800-x. i hand weigh each 800x load as it measures like crap. I tried to check the pressure ring but the whole case measures the same coming out of the LW barrel. is that normal. the barrel so so much tighter that the case hardly expands and its fully supported so no bulging.

[_The_Shadow]

This is just food for thought...
You are starting to get some wipe and smere from the primer metal flowing into the striker/firing pin hole, while the pistol is handling the powder charge the shearing of the plating or nonplated primer materials can get inside the striker/firing pin hole to cause problems with primer strikes if shooting these presist. If the wipe from the striker/firing pin gets worst you risk possible damage to the striker/firing pin itself.

BTW, Some of my loads have primers looked the same.