Hey erbody,
Hoping you all can help me out. I started to refine my typical load as well as try a few other powders in my high power/service rifle M16A4. I was shooting 77gr SMK's in LC brass (mix of years since 2000 not separated), CCI 400 primers, 23.5gr Varget. I would get the occasional AR ejector marks once and awhile but nothing else.
I recently worked some ladder tests with 8208XBR (Top) and N540 (Bottom) with the same components in 2x fired brass. Here are my findings:
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I started getting increasing pancaking of my primers, ejector marks, and occasional extractor marks/burrs starting at the second load of 8208 and the fourth load on N540. Totally normal in a ladder test right...?
Here is the problem, I loaded up some 10 shot groups of N540 at 24.6gr hoping to get a 600 yard load and 23.7gr of Varget (added .2 gr) hoping to get a little more than 2600 FPS. I first fired a 5 shot control group of 77 gr OTM AAC factory ammo (fly's at about 2815 out of my rifle; it's good stuff!). Everything seemed to have followed the trend of pressure signs. Pancaking is especially more prevalent. Here are a few pics:
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I'm shooting a Bartlein Barrel that was manufactured at a time know for premature barrel extension wear out. Could these signs be a sign of that? The 23.7 gr load of Varget shot .863 MOA @ 100 and the function was fine. I've never shot a barrel out but I got the upper from a good friend and have put about 700 rounds through it.
Is my barrel that picky? I wouldn't expect such a drastic pressure sign jump with .2 gr of varget. I will be monitoring the 23.5gr load of Varget at my next practice. Maybe I'm over thinking this and need to just dumb down my loads but it really doesn't feel like I'm reaching for any extreme's. Perhaps I need to be humbled.
Any words of wisdom would be greatly appreciated. Thank you for your time.
Ryan