Author Topic: Which cannelure????  (Read 574 times)

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Offline drdougrx

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Which cannelure????
« on: November 21, 2008, 03:27:02 AM »
Hi All,

It probably doesn't make any difference but, I load Hornady XTPs, 300gr, 44cal, 20gr H110.  I load to the lower cannelure.  Is there any reason to load to the upper cannelure??  The overall cartridge fits the cylinder of my SW29s, but, I was just wondering.  What do you think?????
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Offline Grumulkin

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Re: Which cannelure????
« Reply #1 on: November 21, 2008, 03:51:45 AM »
First of all, the only reason a bullet would have to be crimped in a cannelure would be if it's to be fired in a handgun with a magazine or cylinder.  If it's a single shot handgun, you can seat the bullet to any depth you like and not crimp it.

If the bullet doesn't project too far so it contacts the lands or keeps the cylinder from turning it would be best to seat to the cannelure nearest the base of the bullet.  This will give you a little more case volume and better velocity potential.

Online Graybeard

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Re: Which cannelure????
« Reply #2 on: November 21, 2008, 03:53:00 AM »
So long as they fit no need to go shorter. Going shorter reduces case capacity and thus you must reduce powder. I drop a minimum of 1.5 grains if using the shorter length and seem to get about same velocity that way. If you were using them in a lever rifle you might find it makes a difference but so long as they fit your cylinder stay with the bottom cannelure and longer OAL.


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Offline drdougrx

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Re: Which cannelure????
« Reply #3 on: November 21, 2008, 04:29:09 AM »
Interesting...appears to be a long cartridge overall. but, fits nicely in the cylinders and doesn't in anyway interfere with function.  Just wondering if I was missing something.
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Offline buck460XVR

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Re: Which cannelure????
« Reply #4 on: November 21, 2008, 09:11:57 AM »
the load manual doesn't give the COL for the load you're using?  According to the Hornady manual, you are right at max(they list H110max @20.1 and w296max@19.9), and seating the bullet deeper than tested would produce more pressure.......yes?

 Hornady gives 1.600 for COL with the 300 grn XTP.
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Offline drdougrx

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Re: Which cannelure????
« Reply #5 on: November 22, 2008, 03:19:49 AM »
Thanks Buck

I just heard back from Hornady's Tech group and they said said the same...use the lower one.  I will.  Thanks!!!
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Offline Catfish

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Re: Which cannelure????
« Reply #6 on: November 22, 2008, 10:26:05 AM »
Personally I never pay any attention to the cannelure on a bullet. I load them to the lenth I want them and almost never crimp in the cannelure if the bullet has one, in fact I almost never crimp in bullets. I do have some heavy kicker that I have to crimp, but even with them I crimp the minimum nessary to hold in the bullet under recoil.

Offline gypsyman

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Re: Which cannelure????
« Reply #7 on: November 25, 2008, 05:01:23 AM »
I've talked with several of the guys that work for Sierra. And wondered why the company's put the cannelure where they do. This is what they told me. The first .44's had shorter cylinders, so the bullets were seated deaper. Just to clear the front of the cylinder. Sierra doesn't want the shooters with the older guns having lenght problems with ammo. Unless you get one of the older S&W's, keep doing what your doing. Your probably getting better accuracy by cutting down on the bullet jump anyway.  gypsyman
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Offline Steve P

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Re: Which cannelure????
« Reply #8 on: November 25, 2008, 10:04:46 AM »
You want your bullet to have the least amount of jump and still fit in the chamber.  On most of my guns, this usually means the first piece of brass and the first bullet are used to set the dies for the press, and tailor the ammo for the gun.  In this case, I would seat the bullet, and adjust length to the nearest cannelure allowing the round to chamber and function in the gun. 

Second comment made in the posts above were regarding crimp.  Someone said you can seat a bullet to any length you like and not crimp it.  I will not dispute this as it is likely true.  (You can do most anything you want with your own press and components.)  However, I will state with fact, if you do not crimp a load that should be crimped, you are not securing the accuracy potential of the load nor of the gun you are shooting.  Most handgun loads rely on taper crimp, roll crimp, or both to obtain optimal ignition and bullet acceleration.  Just like launching a jet off an aircraft carrier, if you don't get the acceleration at the right time, it just might not work right.   

Please don't take this wrong.  There are some handgun loads that do not require a crimp.  I shoot a 7mm Super mag in a T/C.  It has a 1/10" neck.  No  crimp.  The neck basically holds the bullet in place to center it in the barrel.  If you use the right combination of primer, powder, and bullet, you get excellent accuracy and a relatively clean barrel.  Use the wrong powder or primer, and you get messy bore and shotgun patterns.

I know of NO .44 mag load that does not require a crimp.  Most powders used in .44 mag cases rely on that crimp to hold the bullet in place until the powder has started to ignite.  On a good load, the powder ignition is usually near 100% before the base of the bullet leaves the case.  On some not-so-good loads, the ignition does not accel to 100% and with revolvers, you get little bits of unburned powder spitting between the barrel and cylinder gap.

I shot my SBH .44  4 5/8" barrel about 30 shots two weeks ago.  Two cylinders (I only load 5) were fired at a 6" gong at 200 yards.  I hit it 2/5 first time and 3/5 second time.   This load was averaging 4 shots of 5 under an inch at 25 yards off the bench.  I seat bullet, taper crimp, then roll crimp into crimp groove on the bullet.  I did leave black marks on my sand bag, but had no cutting into the bag.  Cylinder is nearly clean, as is the barrel.  I could have easliy shot another 50 rounds and not had unsightly smoke marks on my stainless finish. 

My little gun is not only accurate due to the load, but also stays a little cleaner.  There are advantages to crimping the bullets in place over an above preventing bullet movement from recoil.

Your gun, your call.  Consequences of not crimping loads for a Smith 29 would become aparent faster than I typed this message.

Shoot straight and keep 'em on the target.

Steve :)
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