What is the purpose of the Pressure Ring?

[dmoran]

^^^ +1 ....... I like to disagree with Boyd when I can...lol .... but I'm in totally agreement with him here !.!.!

 

[Bob Sebold]

Sorry guys for giving wrong information. I have not made any bullets myself so all my info was from people who have. I do not know how someone else does what they do to make their bullets or how they get a pressure ring. I am not saying they shoot bad either. I know for a fact many shoot very well. If you would reread my post, I think you would see I said they add nothing for accuracy. If they did, .... why wouldn't everybody use them in different configurations and styles until the almighty magic bullet is finally created? I also said I do not think smaller pressure rings significantly add to inaccuracy. I will not comment on why someone else's bullets have them and I am not saying if they have them the bullets are no good. I have a few ideas why they might be getting them, but since I have never built one myself I will remain silent as to why someone else has them. Please, Please tell me how they add ANYTHING TO ACCURACY! If I am wrong, I would be glad to buy you a beer, in fact I would be glad to buy you one just to discuss it with you. Ribbed for your pleasure!

 

[BoydAllen]

Bob,
I am not sure that anyone can really prove what pressure rings do, but I can state with some confidence that having a large one does no harm, based on shooting bullets that have them. Do you shoot many short range FB bullets from custom makers? A couple of examples of bullets that have done well, that have substantial pressure rings are the Tucker #3s that Cecil Tucker makes (.2437 pressure ring) and the latest Berger Column bullets. I forget the number, but a friend who recently bought a couple thousand remarked that these latest ones are larger in that dimension than the first ones that he tried. While I don't think that the size of a bullet's pressure ring defines its quality, I am positive that having a rather substantial one is not detrimental.

 

[Alex Wheeler]

I have had issues with larger pressure rings on bullets if they are seated below the sized part of the neck. In my .284 I get 75 lbs of seating force, when the pressure ring goes below the sized part of the neck the force drops to 20 lbs. The pressure ring has expanded the neck and made my selection of neck bushing irrelevant. I have no issues when the freebore is long enough that the pressure ring is held by the neck.

 

[Bob Sebold]

No Boyd, I have not shot any short range bench rest. Only mid & long range f Class, so my experience is with boat tailed bullets. I never said they would not shoot if they had a large pressure ring, just said it did not aid in accuracy. As in improve it. I refuse to believe that after you subject a bullet with 40 to 60 thousand psi of swaging pressure and a few inches of barrel there is anything left whatsoever of the pressure ring. That said, if you tried to tell me they seated better or more concentric I might agree with you and ask how you get that accomplished. I have never found pressure rings to be a problem, but I could see how large ones or different sized ones could be a problem with neck tension. I spend more time on a case getting neck tension right (what I think is right) then anything else. I highly doubt a test could be constructed to really test the effect a large pressure ring has versus a smaller one. Maybe one of the members who lives for that stuff could try to test this. This is about all I have to say about this subject. Eric, you can put your popcorn down now.

 

[Alex Wheeler]

I guess I should have added that my experience is only in long range BR. And I think annealing exaggerates the problem.

 

[M14AMU]

Hmmm....let's see...on BT bullets there is a TAPER!! And when forming or seating the lead core...pressure is applied by a core seating stem and the bullet base taper is formed by a base forming die. With pressure being applied and the core is in contact with the bottom of the jacket it tends to move forward at the same time the upper portion of the lead core is moving downward and where these two collide you have a pressure ring formed! It's only slight....but it's there!!

 

[Alex Wheeler]

What is interesting to me is, some lots don't have it. On my lot of hybrids I have a .0007 " pressure ring (.2439). I was given a box of the new lot, no pressure ring that I can measure. The whole bullet measures .2430

 

[BoydAllen]

I learned something here today about BT bullets. Indeed they can have pressure rings. I am going to see if they are on any of the production (non Berger) bullets that I have on the shelf. I'll be back. ...

Checked several old factory bullets (6mm) Soerra 100 gr. SPBT, shank .2433 no pressure ring (this is the brand that I have the most experience with for BTs); Speer 85 gr. spitzer BT, shank .2428, pressure ring .2433; Nosler 100 gr. Solid Base, shank .2429, pressure ring .2430; Hornady 87gr. BTHP, shank .2430, pressure ring .2433

It would seem that I made the mistake of ASSUMING that what was true of Sierra was true for all. I might add that one should not assume that one measurement will tell the story of a diameter, as not all bullets were perfectly round. I have no idea if this matters. My apologies to the long range fellows for my excessive extrapolation.

 

[gilream]

I have had issues with larger pressure rings on bullets if they are seated below the sized part of the neck. In my .284 I get 75 lbs of seating force, when the pressure ring goes below the sized part of the neck the force drops to 20 lbs. The pressure ring has expanded the neck and made my selection of neck bushing irrelevant. I have no issues when the freebore is long enough that the pressure ring is held by the neck.

thank you sir...this is what I was looking for in my OP.