Oh gawd not another Valkyrie post...

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Here is the .224 Valkyrie product Manager from Federal talking about the bad PTG reamers with too long of a freebore and the issues it created!
 
Okay, after waiting on UPS to finally get back to work and then spending a week in the hospital with the little person, I finally got to load some Valkyrie ammo. After deburring flash holes, uniforming pockets, expanding necks and applying a light chamfer, my brass was ready to go. I have to say, this Starline brass is not impressing me one bit. The first bullet I seated felt like dragging a plastic sled full of firewood across a gravel driveway. So naturally, I pull the bullet to take a look, scored the entire length of the shank. I bust out the expander die and re-work all the necks and chamfer a bit deeper, seemed to help some but I can feel that there is a distinct lack of consistency in neck tension. Some bullets glide right in and others require noticeably more force to seat and are .01" longer to the ogive. It's almost like they forgot to anneal the brass one last time before sending it out the door.
 
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Okay, after waiting on UPS to finally get back to work and then spending a week in the hospital with the little person, I finally got to load some Valkyrie ammo. After deburring flash holes, uniforming pockets, expanding necks and applying a light chamfer, my brass was ready to go. I have to say, this Starline brass is not impressing me one bit. The first bullet I seated felt like dragging a plastic sled full of firewood across a gravel driveway. So naturally, I pull the bullet to take a look, scored the entire length of the shank. I bust out the expander die and re-work all the necks and chamfer a bit deeper, seemed to help some but I can feel that there is a distinct lack of consistency in neck tension. Some bullets glide right in and others require noticeably more force to seat and are .01" longer to the ogive. It's almost like they forgot to anneal the brass one last time before sending it out the door.

You didn't mention full length resizing the brass. FWIW, I always full length resize new brass and then trim, etc. etc. But that brass does sound somewhat brittle from your description.
 
I full length size new brass with a few exceptions. Starline recommends at a min of running a expander through the necks to true them up and to remove the preservative that is on them. With this coating you are going to have different neck tension. It would not hurt to run them through cleaner like any fired brass. I used a expander but I also used some solvent before hand. And yes you will have different neck tension due to variation in neck wall thickness. The only way to fix this is to turn the necks, which I did.
 
There's a lot of info about out of spec chambers online that is 100% wrong, especially the method that is described to measure freebore using a flat based bullet turned backwards or .224 inspection pin. All this method does is measure the OAL of a cartridge with the bullet touching the point in the leade that is at most 0.224" in diameter. The freebore is 0.2246" in diameter at a minimum so the inspection pin will not touch any point in the freebore of the rifle chamber.

The freebore minimum diameter is 0.2246, and the leade is cut at 1.5 degrees. A little trig shows that the distance down the bore going from .2246 to .224 at 1.5 degrees is (remember to turn diameter into radius) 0.0006 / 2 / sin(1.5 deg) = 0.0003 / 0.02618 = 0.01147 or about 11.5 thou. JGS says their reamers are +0.0005 in diameter so they could see up to 0.00055 / 0.02618 = 21 thou for the perfect 0.224 inspection pin down the bore. SAAMI spec has diameter tolerances of 0.002", so if we had an absolute SAAMI max chamber with a freebore diameter 2 thou bigger in diameter than minimum, or 0.2266" (radius = 0.1133") then we would see even more jump. so take (.2266 - .224) / 2 = .0013 and divide by sin (1.5 deg) = 0.0013 / 0.02618 = 0.0497 which is almost 50 thou and the chamber is still "in spec".

You can take a cavity back bullet and machine the base off to the "sealtite" band, which is right around 0.225" in diameter, and use a Hornady OAL gauge tool to measure the length of a cartridge with the backwards cutting edge bullet seated with the sealtite band touching the leade very close to the end of the freebore. Then, for example, if the freebore diameter is 0.226" and the diameter of the sealtite band is 0.2252" then you should measure an OAL around 1.6882". When I do this with my barrels I get an OAL of 1.6880" indicating that the diameter of the freebore is more like 2.2257" which is a bit bigger than the minimum diameter plus half the tolerance. This assumes that the lands are perfectly at 0.219" and all other dimensions are MINIMUM SPEC, which is highly unlikely.
 
Interested in this thread, as the Valkyrie has a lot of potential for long range in the ar15, just have read about too many issues in the past, sprinkled with some flurries of greatness.

@carnaby how are the reports of your Valkyrie barrels doing? Was waiting for the teething pains to either remedy themselves or get worse on the Valkyrie to see if I want to jump in.

My 6.8 SPC 20" barrel of yours is very nice.
 
I've got a post up from my recent range trip with the new Federal Gold Medal Match. Great stuff. Sierra modified the bullets and I was able to shoot hand loads and the new factory 90 SMK side by side. Impressed by both:

http://www.bisonops.com/2019/04/20/new-federal-gold-medal-match-224-valkyrie-ammunition/

That 24" barrel can't miss. On the other hand, I have another barrel, 22", that is a little less satisfying. That's how it is with production, or really any barrels, you'll always have some that are superb, some that are good, and some that don't measure up. With that new FGMM load, none of our barrels should shoot 5-shot groups worse than 1.5MOA consistently. I expect that most will shoot a lot better. As always, if anyone ever gets a clunker from Bison Armory, we'll get it sorted out.
 
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