I have quite a store of GS custom bullets and I noticed on his web site that he does not recommend crimping his bullets. I have e-mailed him numerous times for a rational for this and have had no responses from he or his staff. Whats up?

FIRST OFF WHAT YOU SHOOTIN ??
target loads I do not crimp.
Most hunting loads I do not crimp.
tube magazine feed repeaters I crimp and use flat or round nose bullets.
My heavy maqnums i crimp because the recoil will move the seated bullet
My auto loaders i crimp for the same reason as the maqnums.
I crimp some loads just to change the pressure curve.
slower powders burn rate, work better when crimped.

quote:

My heavy maqnums i crimp because the recoil will move the seated bullet

Generally one has to crimp from 375 H&H and up. However with a down load to to 9,3x62 velocities it is not necessary. Regargless of crimp or not, always make sure you do not have a LOOSE bullet in the neck of the case. I have seen problems with certain dies with an overly large expander ball, which then bumps up the neck too wide and you will have a loosely fit bullet.

The Lee crimp die is one of the best and I have recently bought one out of curiosity rather than necessity. I must say that I have been very happy with the results - it is a lot more gentle on the case. You also need to crimp where the bullet provides the crimping groove so as to have an effective purchase.

Proponents of crimping claim the burning is better, but by and large I think it counters the recoil effect on the bullets in the magazine that can slam forward against the magazine and so bump bullets deeper into the case. It is always good insurance for DG hunting.

Warrior

The GS custom bullet web site does not recommend crimping any of their bullets. These bullets are for big game hunting. I know the reasons for crimping bullets as Warrior pointed out. My question is why would the manufacturer of banded bullets suggest not crimping. I have e-mailed Gerard at GS several times and still no answer.

Most of my rifles are in the 375 and above class and most are pushing heavy for caliber bullets at from 2150 to 2400 f/s. Thanks for the help.

Just an assumption on my part but, Speer at one time claimed crimping a bullet with no crimp grove (Lee factory crimp) compromised the jacket/core integraty and could cause seperation on game or poor accuracy if it became unblanced because of it. I haven`t seen anything on this in a long time now, although Lee countered and recommended against useing Speer bullets for quite some time. It may be GS follows the same line of thought. The GS bullet has built its rep on being a very predicable bullet in game. Again just a thought on this I don`t really know for sure.

quote:

Speer at one time claimed crimping a bullet with no crimp grove (Lee factory crimp) compromised the jacket/core integraty and could cause seperation on game or poor accuracy if it became unblanced because of it.

Conventional lead-core bullets without crimping grooves have a frail structure.
They are not bonded as well, and so it stands to reason that the lead inside the
jacket will become loose and it is not a good idea to crimp them.

On the other end of the scale, crimping grooves generally weaken the jacket as well.
I have seen some of them that break in half.
Gregor Woods posted some examples in the Man Magnum.

Warrior

The road to hell is paved with good intentions. LB404, please accept my apology for the lack of a reply. Every time you asked the question I intended to make the drawing to illustrate why we make the recommendation and every time something else side tracked me very effectively.



We reckon that crimping is not required with a drive band bullet because the brass springs back slightly between the drive bands when the bullet is seated. This acts as a multiple crimp but has great precision because the variables from cartridge to cartridge are held to a minimum. When a normal crimp is applied to a case, varying case lengths, however small, will cause the crimp to vary and bullet pull weight will vary also. Should you find that a drive band bullet moves under recoil, first check that the case neck is sized down as it should be, then check that the sizer button is not over size and, if both are within spec, only then should a crimp be applied. Make sure that the crimp falls between two drive bands.

I have fired up to nine shots over a cartridge left in the magazine of my 375H&H and found no movement of the bullet in the case.

Thank you Mr. Gerard, very useful info, especially the .375 experience.