Minimum Neck Grip

[JerryK]

On a single-shot action, 6.5 wildcat, what do you think is the minimum bearing surface the bullet/cartridge neck should have to maintain accuracy? I'd like to seat my 140g bullets out as long as possible. .20? .30?

 

[Bobthenailer]

I was always told the minimum seating depht is one bullet diameter. so in your case that would be .264"

 

[rcw3]

If you ask a general question you will typically get a "one size fits all" answer (just like the "bullet diameter" answer you received).

That being said, it somewhat depends on what the use is that requires the neck grip.

I have never found the one caliber rule to be completely viable and many, many times run with much less than that.

If you are talking about hunting ammo that will be banging around in a pocket or pushed and shoved around or subject to rough handling and maybe used magazine feed maybe in a semi auto rifle, then the one bullet diameter rule is probably a good "rule of thumb" for the sake of durability to withstand the rigors the ammo is expected to endure.

If you are talking about an accurate single shot bolt gun type application where the ammo is kept in a protected box until used at a shooting bench, etc. then the one bullet diameter rule is of little value and you can typically run with a fair bit less than that. I remember shooting a match at 600 yards with Berger 6mm 105 VLD's out of a very long throated rifle and there was only about .100" holding them in the case but the rifle shot great and consistently.

Look at very accurate cartridges like the 6mm BRX that have very short necks (less than one bullet diameter). Who would say that a short neck hurts their performance? Then you have people shooting a cartridge like the Dasher that has a neck length of about one bullet diameter, but the bullet and throating makes it so the bullets are a fair amount up forward of the neck shouulder junction, and it still shoots very well.

Robert Whitley
www.6mmAR.com

 

[JerryK]

Thank you for the replies. I'm considering improving the 6.5x47 even more than I have already, and moving the shoulder as far forward as possible (for 1000yd benchrest). Even so, I don't think I can get to 2900 fps with a 140 in my 31" barrelled BAT action. I currently get 2940 fps with a 130 JLK, but had hoped for less wind drift with the heavier bullet. I love the cartridge, but I'm also looking at a 260 improved to do the task. I think the smallest possible, most efficient cartridge to make speed is the best.

 

[savet06]

http://sgrcustomrifles.com/30-wolf-pup/
Here is an interesting article on a cartridge that Stan Ware developed for short range hunter class shooting. It is obviously not meant for long range, but I have seen some of the groups that have been shot with it and it works well. Maybe Mr. Nyhus will chime in and help shed some light on the subject. I know that the long range game is much different in regards to requirements for case sorting, etc...but maybe this type of extreme example could cross over.
Good luck in your quest...
Mike

 

[jb1000br]

Thank you for the replies. I'm considering improving the 6.5x47 even more than I have already, and moving the shoulder as far forward as possible (for 1000yd benchrest). Even so, I don't think I can get to 2900 fps with a 140 in my 31" barrelled BAT action. I currently get 2940 fps with a 130 JLK, but had hoped for less wind drift with the heavier bullet. I love the cartridge, but I'm also looking at a 260 improved to do the task. I think the smallest possible, most efficient cartridge to make speed is the best.

With Reloder 17 and a 140 you WILL get 2900...and probably more.

JB

 

[JerryK]

I hesitate to depend on R17. It seems more often than not R17 isn't accurate in a lot of barrels. This may be a bad rap, or it may be that there's too-much late-burning turbulence in the barrel and it disturbs the bullet exit. I've read of more shooters giving it up, even though it's fast, because they couldn't get the accuracy they wanted. Maybe they didn't try the right combo. R15 works fantastic for me, I just want more in the case. I think I'm going to move the 40 degree shoulder forward until I have .160 neck bearing, and move the bullet out. I'm working on the drawing now. I read that David Tubb said he used .175 on magazine-fed rounds and it worked fine. Even the radical .080 bearing surface cartridge mentioned in the Stan Ware article worked.