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Emmett
04-06-2009, 04:30 PM
How important is case length if you are dealing with a rimmed case?
Thanks in advance.
Emmett

versifier
04-06-2009, 04:51 PM
That depends on the shape of the case and if it needs to be crimped.

With revolver cases, the actual length doesn't matter as much as the consistancy of all the cases in the batch - they should all be the same length so the crimp will be applied equally. Same way with lever action cases.

With rifle cases though, it's important not to exceed the max length because of chamber dimensions, rimmed or rimless. A case that is too long for the chamber can cause pressure spikes because the bullet is prevented from exiting the case normally.

If you do not need to crimp the cases, and they do not exceed the max length, considerable variations in length within spec won't cause any problems, but the bullets will each seat at slightly different depths despite consistant OAL, so they might look weird. I can't imagine it would help accuracy of the load any with neck tension different in each individual case. They would feed and function properly, though.

kg42
04-06-2009, 06:40 PM
By the way, I have read on an other forum that all the new Hornady Leverevolution but the 30-30 and an other similar round (32Sp?) had short cases in order to accomodate the wonder bullets.
This would prevent crimping with standard dies.

Anybody has experienced with this?

kg

runfiverun
04-07-2009, 02:40 AM
i have heard they were shorter also.
i don't tink they would be short enough to not be able to crimp them even in a normal die.
since most every rimmed case i can think of is normally crimped,them being the same length and shorter then the neck area of your chamber is where it becomes important.

missionary5155
04-10-2009, 10:27 AM
Good morning
The crimping die is easily shortened to accomidate shorter brass. Bench grinders and little later polishing can quickly remidy manny inconvienances.
Mike in Peru
HE is Risen !

1Shirt
04-27-2009, 06:34 PM
I have never trimmed a 38S,357, 44S, or 44Mag. However I check my 444's and 45-70's very closely, and trim to recommended minimums.
1Shirt!:coffee:

Jim_Fleming
05-04-2009, 01:40 AM
Like everyone else has said, Emmett....

Case length is important to consistency. Case Length is important to crimping.

If you're just loading up a few .30-30's they'll require crimping to keep the bullet in place. Or .38's or .357's or anything like that.

Actually crimping is to keep recoil from pulling the cases off of the bullet in your magazine/cylinder of the firearm being discharged.

Take Care,

Jim



How important is case length if you are dealing with a rimmed case?
Thanks in advance.
Emmett

armyrat1970
05-11-2009, 09:13 AM
Many state that when loading for revolvers you need to crimp to stop the boolit from jumping forward out of the case and causing the cylinder to lock up because the cartridge is to long. Others state than when loading cast boolits for a bolt, or lever gun, if the neck tension is good enough to hold the boolit true there is no need for a crimp. Don't you have the same inertia from recoil with either? I really don't understand how a boolit that is not crimped can jump forward out of the case when fired through a revolver. In recoil everything is moving backwards. What causes the boolit to jump forward? Is everything else upon firing moving so quickly that the boolit just stays suspended through the recoil because of it's weight? I just don't understand. If anything to me because of the recoil and without a crimp the boolit would seat deeper. Of course this may not be the first time I have been wrong but I just don't understand this concept.

runfiverun
05-11-2009, 03:36 PM
the boolit don't jump forward it stays where it is and the gun jumps backwards.
something about a body at rest thing, from physics class.
if you have enough friction to overcome this effect it wont go anywhere, if not the cartridges get longer.

versifier
05-11-2009, 05:01 PM
...and the rifle usually has a whole lot more mass which slows the recoil impulse over a longer duration. But, there are many rifle cartridges that produce enough energy that they need to be crimped for the same reason. For instance, if you load up a .45-70 the max load a Ruger #1 can handle (almost a .458mag) and fire it, two things will happen: first, cast or jacketed, the bullet will back out if it is not firmly crimped, and second, you won't even think about firing a second shot out of such a light rifle. :mrgreen:

Jim_Fleming
05-12-2009, 10:03 AM
armyrat:

What happens is that the recoil of the firearm actually pulls the brass off of the bullet.

For example: Since the brass of a .357 Magnum case is somewhat lighter than the bullet, it's easier for the brass to be moved backwards during the recoil than it is for the bullet. Yes the bullet is for a fact subjected to the exact same recoil, but inertia comes into play here.

Think of a stalled car... When someone is trying to move that car by hand you know that it takes much more effort to start the car moving than it does to keep the car moving.

Same thing with the casing of the cartridge versus the bullet, it's easier to start the case moving than it is to get the bullet to start moving.

Jim

Echo
05-21-2009, 05:46 AM
But hot pistol rounds should be nicely crimped - maybe even heavily crimped. That ol debbil inertia...
Rilfles typically are heavier, so there is more mass to absorb the recoil, thus less chance for bullet expulsion.

Jim_Fleming
05-21-2009, 09:43 AM
Echo, thank you for saying so... I guess after re-reading my post I did for a fact forget to say that rounds of that nature need to be crimped...

Thanks again, Sir.

Jim

armyrat1970
06-03-2009, 11:16 AM
armyrat:

What happens is that the recoil of the firearm actually pulls the brass off of the bullet.

For example: Since the brass of a .357 Magnum case is somewhat lighter than the bullet, it's easier for the brass to be moved backwards during the recoil than it is for the bullet. Yes the bullet is for a fact subjected to the exact same recoil, but inertia comes into play here.

Think of a stalled car... When someone is trying to move that car by hand you know that it takes much more effort to start the car moving than it does to keep the car moving.

Same thing with the casing of the cartridge versus the bullet, it's easier to start the case moving than it is to get the bullet to start moving.

Jim

Jim thank you. Understand. Does this theory hold true for cast boolits as you have no crimp groove? At least not the ones I cast. I can apply a crimp in the lube grooves if needed. But I think they would still have some slack. Would proper neck tension itself be enough to stop the cast bullet from pulling out of the case from inertia. My Lee dies apply a roll crimp. I may possibly have to get the Lee Factory Crimp Die to apply a crimp on the bearing surface depending on bullet seating for correct OAL.

versifier
06-03-2009, 05:35 PM
Usually, when a cast bullet is properly sized for the bore, it is greater in diameter than a jacketed bullet for which the neck expanders in the dies are designed. This means that there is quite a bit more neck tension than there would be with a jacketed bullet. That said, it is often necessary to crimp a cast load anyway (especially a rifle load) for uniform ignition with the reduced powder charges used, even in a bolt action or single shot which normally wouldn't require it. You have to experiment with the load and the firearm though to see if the recoil is enough to pull the bullets and if crimping makes a difference in accuracy (which, even in a Contender/Encore it often does).

Jim_Fleming
06-04-2009, 12:23 AM
Yes, ArmyRat, in *MY* opinion only.

If you're shooting a straight walled case, when you "bell-mouth" the case you need to crimp it anyway... So even if you were using a jacketed slug, you're going to "crimp" the case against the side of the bullet, whether you crimp into a cannelure, a crimping groove (most cast pistol bullets have a groove) or simply seal the case against the side of the bullet. I realize that doesn't answer your question completely.

But, I think, NOTE I said think, that when you're using cast rifle bullets that the same principle applies. I've never shot cast bullets in any sort of rifle. For that matter I've never cast rifle bullets.

If you're shooting reduced loads in a rifle, I would *think* that the recoil isn't going have the same level of effect, since you're not going to be shooting a heavy magnum load, etc.

But to tell the truth I am convinced there are some *HIGHLY* experienced cast bullet rifle shooters on here that can definitively answer your question, where as I'm almost guessing here.

Hope this helps,

Jim


Jim thank you. Understand. Does this theory hold true for cast boolits as you have no crimp groove? At least not the ones I cast. I can apply a crimp in the lube grooves if needed. But I think they would still have some slack. Would proper neck tension itself be enough to stop the cast bullet from pulling out of the case from inertia. My Lee dies apply a roll crimp. I may possibly have to get the Lee Factory Crimp Die to apply a crimp on the bearing surface depending on bullet seating for correct OAL.

runfiverun
06-04-2009, 01:35 AM
quite often with rifles the act of chambering a round will engage the nose into the rifling if you have enough neck tension the boolit will not be forced back into the case and the engagement will act much like a crimp.
now the rub some boolits don't like that much neck tension [you might actually be sizing the boolit smaller with the tension]
you gotta really mess with rifle boolits sometimes.
fit is king but even when you think you have the perfet fit they still won't shoot well.
if the cast boolit you are talking about is a lee with all those micro bands they are all crimp grooves.
other boolits you just crimp over the driving band on the front.
i have some of lees 240 gr swc's with the microbands i seated in 44 special cases and had 2 of them with messed up primers and i can't beat them out of the cases with a hammer type puller and i am afraid to mess up the brand new cases. they have no crimp on them.