primer problems need wisdom!

[NoNOS67]

well i was struggling to fit 26 grains of varget in those cases before the bullet and your saying you use 27.5... if you use this much powder obviously you wont be crimping these bullets to avoid pressure issues right??

26 under a 55gr pill shouldn't be an issue. If you had the shoulder pushed back too far, that was likely part of your problem.

[GeoffLinder]

well i was struggling to fit 26 grains of varget in those cases before the bullet and your saying you use 27.5... if you use this much powder obviously you wont be crimping these bullets to avoid pressure issues right??

I just reviewed my notes from testing Varget with 55gr loads and realized I stopped at 27gr. Not 28, and decided 26.5 was what would be the right amount to get 3200fps IF you wanted to use Varget for a hot 55gr load. 26.5 didn't show any real pressure sign but was a pain to load and couldn't be done without tamping.

My mistake, Doh, oldzheimers is setting in. BLC2 is the powder that lists max at 27.5gr and can be pushed to 28gr before trouble sets in.

I don't actually use this recipe, I just tested to that point once. Gave me 3230fps range at 27gr and flattened primers to a smear. This is a good bit over what Hodgdon says is max (25.5). Probably about a 55,0000+ psi load. OAL was 2.250" to do so.

You can get that much in (27gr, not 28, Doh again) IF you put it in slowly and tap the case to settle the powder as you do so. Tapping the case gets the grains to align and take up less space. 27gr will fill the case to the brim this way, then when you seat the bullet it compresses the charge a bit. It won't be enough to crush the powder really, but it will be compressed.

This is why I don't like Varget for lighter bullet loads in small cases like .223 PITA to use for it and you never get the full velocity potential. Cheaper ball powders like WW748 and AA2520 or AA2230 work much better here and get you into the 3200fps range easily and safer.

27.5gr WW748 is what I like for 55gr with OAL at 2.245". Any shorter and primers start to flatten. Gives me just about 3200fps out of a 20" bbl AR

[ejor]

as others have said it.s probable caused by a combo of overly sized cases making to much head space and lower pressure loads. the firing pin pushes the case forward and pressure pushes the primer back in a higher pressure load the case would flow back and push the primer back in.

[Trainman]

Switch to CCI primers. Winchester SR primers fit a little looser then CCI 400 or 450. I've had them fall out when ejected.

[ar15barrels]

i need some veteran wisdom to tell me whats going on! i dont think i flattened them?? idk?














what primers look like before firing

This is caused by excess headspace.
Most likely, the shoulder was pushed back too much.
When you chamber the round, the spring loaded ejector pushes the case all the way forward in the chamber until it stops.
As the case shoulder is short, that leaves a lot of room between the boltface and the case head/primer.
Under pressure, the primers back out until they rest against the bolt.
The pressure is NOT high on these loads.
If the pressure was also high and there was excessive headspace, the corners of the primers would be more square.
Also, the higher pressure would cause the case to stretch rearward and the primers would not be sticking out like that.

STOP sizing brass with your die as it is adjusted now.
Get a more reliable way to measure shoulder length and measure some factory ammo after it is fired in your gun.
Using the length of those cases, adjust your sizing die so it is only pushing the shoulder back about 0.002".
I recommend an RCBS precision mic.
I feel it is the most dependably accurate tool sold for this job.
It is much more accurate than the tools that clamp on to a pair of calipers and use bushings to measure.