Questionable Results for 123gr SST
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Sounds like your scope has come loose or maybe the barrel nut or gas block. Since you got a really good group with Hornady factory round I’d test the rifle again to duplicate your first groups. If the factory ammo doesn’t group you have an equiment problem.
If accuracy returns with factory ammo then you have a problem with your reloads. When the rounds failed to chamber I’d suspect not bumping the shoulder back enough or your cartridge overall length is a little long and your jamming the bullet into the lands.Last edited by VASCAR2; 11-14-2017, 07:30 PM.
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A Hornady shoulder bump gauge ought to be part of your process, to assure correct fit to chamber-.002-.0025 shoulder setback about right for reliable functioning. And a base to ogive measurement will assure distance to lands, eliminating jamming the lands. Remember, base to ogive can vary between different lot numbers. Once you have those measurements in hand, load about .020 off lands as a starting point. Both SST’s and 8208 are good in most Grendel’s, with properly prepared brass. 27gr to start and work to 28.2-28.3 for a consistent load. CFE223 my pick, but have had plenty of success with 8208. Or you could pass all that and shoot Black.
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I'm only going to throw out one little tidbit on the chambering issue. I've reloaded a truck load of ammo over the years but none with the wide shoulders until the Grendel. I was having issues with my first reloads using the taper crimp on my die set. It seems its very easy to flair out the shoulder of the case if I tried to put too much of a crimp on the case neck. I was having issues because I was flaring the case just below the shoulder a very tiny amount. Hope this made a little sence.
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Myself and many others do not crimp. Spend the coin on a Redding Type S bushing sizing die, chamfer & deburr your case mouth and seat your bullets with neck tension only.
I had concerns about this route, and tested repeatedly clambering (bolt release - both with a Vltor A5 RE and JPSCS with a heavy spring - and firm taps on the case head, that there is no bullet movement from either. I use a .288 bushing on Hornady brass. No crimp, no feeding issues.Sticks
Catchy sig line here.
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Originally posted by ThunderStick View PostI'm only going to throw out one little tidbit on the chambering issue. I've reloaded a truck load of ammo over the years but none with the wide shoulders until the Grendel. I was having issues with my first reloads using the taper crimp on my die set. It seems its very easy to flair out the shoulder of the case if I tried to put too much of a crimp on the case neck. I was having issues because I was flaring the case just below the shoulder a very tiny amount. Hope this made a little sence.
As a side note - I crimp for ALL my AR platforms.Last edited by bigdaddyflo; 11-16-2017, 02:28 PM.
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Originally posted by Smitters View PostWell good to hear the Lee crimps like that, as I use Lee too. However I am sorting through my brass and I have found quite a few with the ejector marks on the brass. I have also noticed the bolt that I have says 7.62x39!!! I’m not sure but maybe that is adversely affecting my gun.
If you use a .125 bolt with a barrel chambered to use a.136 bolt you’ll have excess headspace which is not good. I saw on a FB user group where a person got a Bear Creek Arsenal 6.5 Grendel barrel and the vendor send a 7.62x39 bolt and BCG by mistake.
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Originally posted by VASCAR2 View PostThe 7.62X39 bolts can be used with a 6.5 Grendel barrel if the barrel was chambered to use a bolt with .125 bolt face depth like the 7.62X39 bolt. JSE Surplus was selling barrels chambered to use 7.62 X39 bolts as well as Black Hole Weaponry/Columbia River Arms. There are a couple of barrel manufacture will chamber your barrel to use .125 X39 bolt or 6.5 Grendel .136 bolt face Depth. I think X caliber will chamber using either bolt.
If you use a .125 bolt with a barrel chambered to use a.136 bolt you’ll have excess headspace which is not good. I saw on a FB user group where a person got a Bear Creek Arsenal 6.5 Grendel barrel and the vendor send a 7.62x39 bolt and BCG by mistake.
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