GS HV ridges & neck tension

14 December 2001, 19:40

I was wondering if the ridges on the GS custom bullets reduced the neck tension on the bullet (less bullet shank is in contact with the case neck so perhaps neck tension would be less)? Do those of you who load the GS HV bullets need to put a crimp on the bullet? I am having a long throated 300 Win Mag barreled (I have a 3.6ï¿½ magazine so I thought I would use it and load cartridges out to about 3.5ï¿½ instead of the usual 3.34ï¿½ for the 300 Win Mag). I wonder if some of the ridges would extend outside the case neck. Any thoughts on this? Thanks, Rufous.

15 December 2001, 12:14

<AVMcGee>

quote:
Originally posted by rufous:
I am having a long throated 300 Win Mag barreled (I have a 3.6ï¿½ magazine so I thought I would use it and load cartridges out to about 3.5ï¿½ instead of the usual 3.34ï¿½ for the 300 Win Mag). I wonder if some of the ridges would extend outside the case neck. Any thoughts on this? Thanks, Rufous.

The 173gr. GS HV has 2 "ridges" not in the case neck at 3.5" OAL.
The bullet is approx. 1.5" long. with 5 "ridges".

Andrew V. McGee

15 December 2001, 13:14

<Don G>

The neck tension is fairly low on the GS bullets due to lowered conatct area and the moly coating. I crimp them in my 416, but do not know if it's necessary in the 300 WM.

I like to crimp as it gives very consistent bullet retention forces. I get lower ES on the velocity when I crimp. I use a Lee Factory Crimp. At $10 it is a bargain.

Don

15 December 2001, 13:29

<Martindog>

Don G,

Where do you crimp them? Do you seat the bullet with a ring flush with end of the mouth or do you seat it between the rings?

Martindog

15 December 2001, 19:59

Gerard

Hi Guys,
Some word on crimping.

If the bullet does not set back under recoil, do not crimp HV or FN bullets.

If the bullet sets back under recoil, check:

1. Remove the decapping pin from the die set and size a case. Starting any bullet into the case now should produce a visible expansion on the case neck. If it does not, the die is not sizing tight enough. If this part is OK then:

2. Spin a couple of thousandths off the decapping pin till the above expansion can be observed.

Seating an HV or FN bullet in a properly sized case causes the brass to expand to accept the diameter of the driving bands and also springs back very slightly in between the driving bands. This gives a good grip on the bullet. Crimping will increase the force required to pull the bullet and increases the initial rise of the pressure curve. This in turn increases temperature in the first section of the barrel as the distance from the case to where max pressure occurs in the bore is shortened. Shortening the time to the maximum chamber pressure point will also limit the maximum speed that can be achieved.

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Gerard Schultz
GS Custom Bullets

15 December 2001, 22:17

<Don G>

Gerard,

Being an engineer, I have to point out that your last sentence should have the added clause "for a fixed maximum permissable peak pressure." I realize that you assumed most handloaders would understand that working restriction.

I will try your method. Do you have to bell the case mouth to start the bullet after sizing that tight?

Martindog,

Since I crimp in order to: 1) prevent setback and 2) to increase bullet retention, I Lee factory crimp so the case mouth ends up just behind one of the driving bands. There is no way a bullet will set back if you do that. It also gives the bullet a .030 running start before the next driving band has to expand the crimp to exit the case. (On my 416, at any rate).

I do not handload to wring out the last 50 fps, and I have consistently gotten great groups in the past. Saeed has some info in the FAQ that seems to indicate an improvement in accuracy with crimping. (But I seem to remember he does not crimp his hunting rounds!)

Do whatever works for your rifle.

Don

16 December 2001, 07:12

Atkinson

With all big bores I turn about .004 off the expander button on my dies and use near a case full of powder to the base of the bullet. In some of the bigger bores I do use a very light crimp, even with the GS FN solid, but I load the big bores several grains below max..I like mild loads in big bores as they don't gain much by velocity..I lean the other way with medium bores (below 375 H&H ) where I normally push the limit of sanity.

------------------
Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

17 December 2001, 09:15

Gerard

Don,
Thanks for adding that, correctly so. We do not bell the cases, only chamfer the inside edge. By "visible expansion" I also mean that if you can see or feel it, however slight, it is enough.

I mentioned a new project we are playing with a while back. We have a .30 cal bullet with a BC of around 0.600 that we pushed at 4200 from a 30-06 this week. We are aiming for 5000 plus. It is not a hunting bullet and the object of the exercise is to make wind drift go away. There was another guy at the range when we were testing. The expression on his face when the Oehler read 4213 fps was priceless.

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Gerard Schultz
GS Custom Bullets

17 December 2001, 02:34

<Don G>

Gerard,

The added clause was strictly for the benefit of novice reloaders, and is redundant for most members.

Have you been contacted by any long range shooters? I mean the 1000 yard benchrest types? Your HV (with a solid nose?) should be a screamer beyond 800 yards. I'm not up on bullet design, what are the factors that affect windage other than BC and velocity?

Don