Home Forums Reloading Big Game Rifles Crush fit cases for accuracy?

If my cases have a crush, bit a bit more than slight crush fit, will this create better acurract or worse? And will ther be any other kind of problems such as pressure? The reason I am asking is because I used a belted magnum collet resizer die and some of my cases are hard to chamber due to a crush fit.
Thanks
Elmer

If you are using the cartridges for hunting, you should invest in a full-length resizer die as well. Eventually you need to full-length size your brass to bring it back to dimensions that will chamber easily. The collet sizer only neck sizes the brass. Personally, I full-length size EVERY piece of brass that I intend to use in big-game hunting situations, you don't want a difficult closing bolt to prevent you from making a shot. And unless you're running a custom BR rig, the crush fit will not help in accuracy, but it shouldn't have any detrimental effects either.
Selmer

Man, if your cases are that tight I sure hope that you have some lube on your bolt lugs.

I think you will find this thread and link I posted useful:


https://www.24hourcampfire.com/ubbth...&topic=0&Search=true#Post2055947

Are you useing a Lee collet neck sizer
http://www.leeprecision.com/cgi/catalog/browse.cgi?1208914165.1024=/html/catalog/dies-collet.html

or one of these?

http://www.larrywillis.com/

Yes i am using the larry willis collet die.
Elmer

From my experimenting using a little crush fit it seemed to hurt accuracy for me.

I would sure make sure you are using a little grease often on the bolt lugs contact area. Galling up the bolt lug and bolt lug recesses contact area is real possibility with excess crush fit.

I`m not a belted case reloader so take this with a grain of salt.
I do believe though, the sizer you are useing is meant to be used when the body of the case close to the belt expands and causes chambering problems. The normal FL sizers stop sizeing just above the belt and sometimes this area grows to a size that interferes with smooth chambering. It is not meant to be used as a FL sizer as it doesn`t bump the shoulder or bring "all" the case dimensions to near their original state as a regular die does. When the body of a case is reduced the brass flows foreward. This can move the shoulder up and cause tight chambering.
Old brass also takes on a "memory" and needs to be sized down farther then new to insure it stays at the desired size. I don`t know if the collet die will do this, new brass might be part of the answer if you wish to keep useing this die.
I`d get a std RCBS, Redding, ect FL die and use it as the instructions suggest and see if my cases chambered OK I think you`ll find you will need the collet die very seldom.

Ol` Joe is correct� It to use it you should be FL resizing

I have one of those �Belted Magnum Collet Resizing Dies� myself� It is more accurate to say I own one� I have never needed to use it. The directions (such as they are) describe a test to tell when that step is necessary� and after 3 loadings of my Win Brass (I have a lot of brass I Cycle through) I have never had any brass �Fail� the test.
I am glad I bought it and I look forward to the day I can use it cause I�m gadget junkie.

+1 on temmi. I tried it on some cases that were too large to fit in my 270wby (fired in another rifle) and I still couldn't get them to fit. I'll try one more time and then it'll be in the ads.......

BTW- I have found worst accuracy on cases that took effort to close bolt, I hate it too. AND the guys are right you better have good lube on the lugs!!

Belted magnum cartridges are designed to headspace on the belt, but that doesn't necessarily lead to the best accuracy. The best accuracy is usually found by sizing the neck/shoulder junction to "just fit" the chamber of the specific rifle you are shooting it in. The theory is that the case alignment is as close to perfect with the bore as you can get it and thus, theoretically, improves accuracy. Stoney Point, now Hornady I think, makes gauges to check this very dimension. Instead of full length resizing, the case is resized just enough to "just fit" the chamber. Size it too much and you get "slop" in the case/bore alignment. Size it too little and you get "crush fit" which leads to lug wear, heavy bolt lift, and difficulty chambering which are all bad things.

This should never be done with an autoloader or for cartridges that will be fired in more than one different bolt gun. It is only used for one specific case in one specific chamber and for bolt guns only.

See if it works for your gun. If not, don't bother with the extra work.

Fast Ed

"If my cases have a crush, bit a bit more than slight crush fit, will this create better acurract or worse?"

Contrary to gun store "wisdom" it just ain't that clear cut. IF a crush fit, or neck sizing or FL sizing or, etc., actually provided "better accuracy" we would all be doing it that way.

Truth, all guns are individuals even if they have consecutive serial numbers. We have to experiment to find our own best load for ourselves.

For it to be a crush fit, the headspace of the cartridge would have to be too long for the chamber.

As mentioned above, a belted cartridge headspaces on the belt, but yu could have a crush fit if the base to shoulder distance is longer than your chamber.

Just my opinion, and I don't have any facts to back it up with but I don't think it is feasable to try to use cartridges that are in this condition.

I suppose one theory in favor of crush fitting would be that the cartridge, and therefore, the bullet is in alignment with the bore, meaning that the bullet starts straight, where otherwise, the cartridge is lying in the bottom of the chamber and the bullet center is slightly below the bore center.

If you can resize the neck just enough to hold the bullet, using a case originally fired in that rifle, so that the bolt closes on the cartridge, with the shoulder lightly touching, but not being crushed by the chamber, would be best.

In addition, if I were hunting with the cartridges, I would full length resize, and make sure the cartridges fed easily through the the magazine and chamber.

It might be different now, but 20 or so years ago when I was into bench resting, that was the way we did it. We used button dies to size the neck to where the base of the bullet came to in the case. The shoulder and body were not sized.

I think a "crush fit" means that you are having to force the breach closed. This is equivalent to using the rifle chamber as a resizing die. The cartridge case is being altered dimensionally by the crush, which means that brass is being moved around somewhere.

In the usual FL die, the crush and brass movement usually results in a longer case. This is no problem usually because the case can be trimmed after FL sizing. However, when the crush takes place in the rifle chamber, the lengthening of the case might possibly result in forcing the case mouth against the bullet at the end of the mouth cut in the chamber. (Obviously this depends on how the chamber is reamed.)

If the case mouth is crimped agaist the bullet as a result of this, it might raise pressures.

Just a thought. Feel free to point out where I've gone astray in my thinking.

--Bob

I think your thinking is right on the mark.

A lot has been said here, but I like to keep things simple. I don't like the term "Crush" in handloading..if you have to force it, something is wrong..agree? After you fire it you can neck size it for that rifle..for awhile. At some point it will be difficult to chamber because the case has grown and you don't have enough headspace to close the bolt easily without forcing it. At this point you have to "Partially" resize the case with a full length resizing die. Run your shell holder up and screw the die down until it touches the shellholder...now unscrew the die about 1/2-3/4 of a turn..lightly tighten the die. Now start sizing your case and trying it in the chamber. If it doesn't fit, screw the die in a little bit, I think Barsness says 1/20 of a turn, whatever that looks like? Keep turning down until you get to the point where the case will just chamber nicely without having to "Crush" it with the bolt..you size it with the die, not the bolt! Viola!..a perfect fit..IMO

Art

Thx Guys, I pfl sized all my cases, a .002" bump of the shoulder from once fired and they chamber easy. The reason i ran into this situation was because I used the larry willis collot die and did not pfl, what that die did was squeeze my ring above the belt back to original spec and it also pushed my shoulder forward, hence the crush fit. So I used that die to get my ring back to spec after firing my shells 3 times and then I annealed the necks and after I pfl sized my cases, you guys still following me lol, So I think i am ok for another round or 2. Thank you
Elmer