6.5 Grendel Primers?
- Thread starter Stugots
- Start date
In the overhead shot are those rims bent or is that an optical illusion? They look seriously bent, which would mean it is extracting with significant pressure still in the chamber.
By the time you see pressure signs for Grendel 6.5, you will be well over the recommended max pressure. What load are you running, and what is your setup?
Rims are not bent, that is a shadow that is cast from the edge of the shell container.
- Nov 3, 2010
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Hmmm, I haven't used Power Pro Varmint, so I don't have any direct experience. Quickload doesn't list it, so I can't give you that data. Looking at what load data I do see for it, 28.8 sounds like it is hot (like around or just over max recommended pressure), but not outrageously hot. If it shoots well and you aren't seeing any other issues, you are probably o.k. I would be careful if you go to a much warmer environment, or do anything else that might push the pressure higher. And if you in fact are bending rims, something is wrong.
If it is an AR, you are just above max load of 28.4grs that Sierra lists. If it is a bolt, you could probably push it a bit more. Your primers look good and the rims look fine to me with no flat spots from the ejector.
Grendel in an AR is a little tricky, use velocity as your pressure indicator. There is nothing alarming about your brass.
Excessive pressures in a factory 6.5 Grendel AR will happen quite a bit before reaching the point where the pressure is evident from reading signs on fired cases.
Working with a pair of (Liberty, a subsidiary of Satern?) 6.5 Grendel 20" and 24" rifles, I (maybe) gleaned some knowledge.
My earliest indication of excess pressure was sooting on the case necks, happening because the case was getting yanked while there was still significant pressure in the barrel, and some of the rims had some damage, too. The cases were still tight against the chamber wall, and were resisting extraction bigtime. Because this was only happening in the 24", I also suspected that dwell time was far longer than the 20" (Both used rifle lengths gas). In this case, the fired primers appeared to be well under max pressure.
I did not recognize all this as "whoa time", and kept incrementing. In fact, the moment I exceeded the bullet maker's powder charge data; the extractor broke. It has now been replaced with a JP Improved Grendel extractor, and has also been dedicated for Speer 90gr TNT bullets; which it shoots like a true Varmint rifle.
The 20" barrel has not shown these serious issues; and this rifle is being worked up for 120gr Gold Dots. BTW, I did purchase a duplicate 20" barrel for long term service.
Will check back with results when I have that part of the 6.5 Grendel project done.
Greg
Working with a pair of (Liberty, a subsidiary of Satern?) 6.5 Grendel 20" and 24" rifles, I (maybe) gleaned some knowledge.
My earliest indication of excess pressure was sooting on the case necks, happening because the case was getting yanked while there was still significant pressure in the barrel, and some of the rims had some damage, too. The cases were still tight against the chamber wall, and were resisting extraction bigtime. Because this was only happening in the 24", I also suspected that dwell time was far longer than the 20" (Both used rifle lengths gas). In this case, the fired primers appeared to be well under max pressure.
I did not recognize all this as "whoa time", and kept incrementing. In fact, the moment I exceeded the bullet maker's powder charge data; the extractor broke. It has now been replaced with a JP Improved Grendel extractor, and has also been dedicated for Speer 90gr TNT bullets; which it shoots like a true Varmint rifle.
The 20" barrel has not shown these serious issues; and this rifle is being worked up for 120gr Gold Dots. BTW, I did purchase a duplicate 20" barrel for long term service.
Will check back with results when I have that part of the 6.5 Grendel project done.
Greg
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