Just getting into 308 reloading. Using 1x fired winchester brass. Resized/trimmed necks only and loaded up with Varget. Measured each out individually. Velocity is about where it should be and grouping well enough. I'm getting 40+ on the spread. I know there could be many reasons but how much could be due to differential neck tensions?
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Splain to me 308 neck tension
- Thread starter donno
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I doubt the neck tension is playing a big roll in your ES. More likely it’s how your dumping powder. Are you using a Chargemaster or similiar electronic dispenser? Or are you throwing by hand?
regadless what I would do is throw your target powder weight 1g shy. Then hand trickle in that last grain by hand...one kernel at a time. This is the way I reload and my ES are typically below 10. And many times in the single digits.
regadless what I would do is throw your target powder weight 1g shy. Then hand trickle in that last grain by hand...one kernel at a time. This is the way I reload and my ES are typically below 10. And many times in the single digits.
yes. they are electronically dumped to the .00. Also, I verified about 30% of weight on another scale.
Buy a Redding type s fls die. Measure neck od of loaded cartridge. Buy appropriate bushing for desired neck tension 2-4thou below loaded cartridge neck diameter. (Buy 2-3 different bushings and play with them till you find the right one) then get a Sinclair expander bushing die with mandrel 1thou below bullet diameter. FLS/Tumble/Trim/Deburr/Mandrel/Tumble/Load
If you are determined to jack around with neck tension then you need to turn the necks. If you don’t then it’s all moot. Certainly the bushing dies will improve your tension consistency. But if you really want to see the results in your chrono data and targets then you should turn the case necks to uniform thickness. Then neck size them with a bushing. And trim.
And the debate continues...
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Is Neck Turning Worth It?
For those out there that turn their case necks what is your process? I'm turning to about 95% and turning down till I get just a touch into the neck/shoulder junction. This is how I was taught years ago and just considered it standard practice. Has anyone found that it just doesn't matter? My...
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Neck tension affects the initial pressure need to start the bullet moving out of the case neck. Pressure has an exponential effect on burn rate and that affects velocity. Exactly what this translates too in real world observation I do not know. There are a lot of variables at play such as primer and powder and volume and they also affect initial pressure. You can turn your necks, trim, and neck size to try and get every case the same neck tension. Or you could forget all that and just crimp 'em. Crimping assures the same initial start pressure everytime. Especially when youre igniting big volumes of slow powder. I crimp my ammo for my semi auto guns where I'm concerned more about reliability than accuracy. My bolt action action ammo doesnt get crimped.
40 ft ES isn't bad if that's all the worse it gets.
Typically the best stuff I shoot is in the 7-12fps SD range which then ends up being 30-60fps ES. 20-50 shot strings.
Typically the best stuff I shoot is in the 7-12fps SD range which then ends up being 30-60fps ES. 20-50 shot strings.
Yes sir. You can use it on bullets with no cannelure.
Lee Precision, Inc.. Factory Crimp Die
Crimps the bullet in place more firmly than any other toolIt is impossible to buckle the case as with regular roll crimp dies. Trim length is not critical. Tests demonstrate that even bullets which have no cannelure will shoot more accurately if crimped in place with the Lee Factory Crimp Die.
I'd use a redding taper crimp die. I have a Lee Crimp die and it sent pressures through the roof. It also deforms the brass with the roll crimp. I measure a factory round coal then hard chamber it and re-measure coal to determine bullet jump from inertia. Then set taper crimp to the tension so that it at least measures the same bullet jump or slightly better than a factory round. Then work your load accordingly to keep pressures acceptable.
Best neck sizing dieYes sir. You can use it on bullets with no cannelure.
Lee Precision, Inc.. Factory Crimp Die
Crimps the bullet in place more firmly than any other toolIt is impossible to buckle the case as with regular roll crimp dies. Trim length is not critical. Tests demonstrate that even bullets which have no cannelure will shoot more accurately if crimped in place with the Lee Factory Crimp Die.leeprecision.com
Agree 100%. Anneal, and use a bushing die that's 1-to-2/1000's below the exterior size of fully seated bullet neck-size. Then shoot a ladder test to find several (>1) shots with consistent velocities, and refine seating depth from there if you want. That technique is getting me low ES' and single-digit SD's. If you're not annealing, not FL-sizing, and not using the right bushing die ... it's tough (in my limited experiences) to get low ES and SD. I don't neck-turn, but I might someday.
