RODSTRADLEY
Well-Known Member
Building an AR308 in 6.5 CM with a 22" Criterion Hybrid barrel and have one question. Is it worth the time to neck turn and use a bushing die for neck tension like my bolt guns?
Neck Tension
- Thread starter RODSTRADLEY
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Do you have a reference link to support the statement that its a proven fact "properly annealed" case necks have the same "grip" as a 0.001 interference fit.
Maybe I am over thinking what you are trying to convey. Its late so if I am off base I apologize.
Sounds like you are claiming this is a standard of what the proper level or state of annealed as well as what level of force this equals at a given interference fit.
In other words if its "properly annealed" no matter how much the interference fit is, 0.001 or 0.005, it will produce the same compressive force on the bullet i.e. what you called grip of this 0.001.
This is considered the proper level of hardness and yield to set as the goal of a case neck that is "properly annealed"?
There are a number of sources that cite 700*-800* as appropriate for conditioning brass. The use of 750* tempilaq allows the user to target this range. With respect to the "grip" I cannot recall the source material but it was convincing enough that I am willing to repeat it. Beyond that I I leave it up to those that question my assertion to research themselves and draw their own conclusions.
I have a 260 and 308 upper. In my experiments. Neck turning didn't gain me enough for the effort. I just use good brass and go. I resize full length back to factory specs. Since the creedmoor bullet sticks out of the case so far I'd put a little more neck tension on than a 223. A lot more mass slamming around in a ar10.
misterc01
Well-Known Member
I measure each case initially at four points to see if the neck thickness/roundness is consistent. If not, then I turn it. I then size it with a bushing die. to get consistent neck tension. I have different size bushings, so I can "experiment " with the neck tension. Right now my rifle seems to like .003. I am getting to the point where I will start annealing the brass at the 5 times fired point, so will see what if anything changes after being annealed.
trailrider121
Well-Known Member
I've been testing neck tension in my hunting rig 6.5 SAUM. From my testing I found shooting different neck tension .002-.004" at distance really shows detail. Lately I find myself with .003-.004" neck tension, as it give really good consistency. Find a good load and just test at long range.
RODSTRADLEY
Well-Known Member
So it seams that I should turn the necks and start finding the best neck tension for this barrel. It will be some time before I can get to my range (to muddy) to try all of this out. So for now thanks Rod
Your AR10 will treat brass differently than the bolt guns. And creedmoors are chambered so tight. turn half of your test loads and see if it makes any difference. My AR10 is hard on brass. And the brass is why hotter then my bolts. You can't pick it up right away. If you size your brass like a bolt gun. You can run into feeding problems. i found that annealing and full length sizing with at least.003 tension. Will keep those 140 class bullets from moving when that bolt strips them and slams them into the chamber
RODSTRADLEY
Well-Known Member
I know where your coming from on the clambering of the semi-auto but I am wanting to shoot just one round at a time. I built a side charger just so it would make it easier to load and manage in a prone position.
