Neck Tension?

tdv75098 · #1 01-08-2005, 01:14 PM

Can anyone tell me if accuracy is enhanced by crimping rifle reloads,(to factory specs),increases accuracy? I have heard that squeezing the bullet allows more pressure to build in the cartridge before it releases the bullet and that this will increase accuracy. Any help?

Varmint Hunter · #2 01-08-2005, 02:43 PM

I have read that a uniform crimp leads to more uniform ignition and a reduction of velocity spread.

Personally, I don't bother with crimping rifle cartridges. It may just add another variable to the loading process and will likely weaken the case mouth sooner than cases that aren't crimped.

As far as accuracy enhancement; I doubt that you will find too many benchrest competitors crimping their cases. That should tell you something.

Handguns and autoloading rifles are a horse of a different color and both normally benefit from a tight crimp.

Just my 2 cents - VH

nowler · #3 01-08-2005, 05:50 PM

do not crimp bolt rifle loads would be my advice.

crimping is for gas guns and handguns. stops the bullet moving about when being battered back and forth by the recoil whilst in the mag of gas guns.

goodgrouper · #4 01-09-2005, 06:45 PM

Usually, more bullet grip (neck tension) decreases accuracy potential. If you run a bushing die that squeezes the case down only a few thousandths, it will produce greater concentricity than a regular die that takes the brass down several ten-thousandths. This will also help accuracy as well as only gripping the bullet minimaly.
Of course you need to grip the bullet as much as needed if shooting something other than a bolt rifle!

sakofan · #5 01-10-2005, 02:13 AM

[ QUOTE ]
Usually, more bullet grip (neck tension) decreases accuracy potential. If you run a bushing die that squeezes the case down only a few thousandths, it will produce greater concentricity than a regular die that takes the brass down several ten-thousandths. This will also help accuracy as well as only gripping the bullet minimaly.
Of course you need to grip the bullet as much as needed if shooting something other than a bolt rifle!

[/ QUOTE ]

Right on. These are my findings as well. [img]/ubbthreads/images/graemlins/grin.gif[/img]

When I seat my bullet, the weight of the handle is the only pressure I use. Make sense??..sakofan..

BountyHunter · #6 01-10-2005, 05:36 AM

Neck tension is a beast unto its own. The general rule is less neck tension is better as long as it is not a hunting bullet and recoild slides the bullet around.

Having said that I have seen bullets that need .004 neck tension to shoot good.

So bottom line is you need neck bushings in order to control neck tension. On 6mmBR.com, Jim Carstenson will convert any die to neck bushings for $35

He will also make a FL neck bushing die for you from a redding body die ($25) and $48 to him. If you want the body die honed to exactly fit your chamber send another $30 and 10 pieces of fired brass. So for $108 you have a custom fit FL neck bushing die.

BH

overbore · #7 02-13-2005, 06:04 PM

I suggest you read the Reding catalog about their bushing sizes as thay suggest an extra 0.001" smaller bushing if your bullets are moly'd to give greater tension. You did not state chamber to neck relationships which, if you are starting out with a new "smoke pole", should have no more than 0.003" for neck expansion. Cordially, Overbore