cannelure question

irishbandit1

irishbandit1

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Hi,I am new to reloading and was wondering if there is any pro's or cons when reloading with a bullet that has the factory cannelure groove.I will be using 180 gr accubonds for my 300 win mag. and 250 gr partitions in my 338 win mag.Any info on these combinations would also be helpfull.Thanks 'Bandit.
 
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I am in the minority it seems, but I have determined that accuracy can be improved by crimping bullets that have a cannelure or crimping groove. Crimping uniforms round to round bullet pull weight, and accuracy is the bi-product of uniformity.

Some bullets with cannelures shoot very accurately. The Nosler Ballistic Tip is a case in point, as these bullets produce exceptional accuracy for a hunting bullet. Accuracy is dependent on uniformity and balance. If the bullet has an acceptable weight to length ratio, a uniform jacket thickness, and no voids in the lead core so the center of gravity coincides with the dimensional center, the bullet should produce good accuracy, irrespective of the presence of a cannelure.
 
Consistent uniform, heavy, crimp can be the key to getting good long range accuracy with Black Powder as well. Inconsistent bullet pull (at least with BPCR) will show up on target at long range as vertical stringing.
 
My $ 0.02

I experimented with crimping using the Lee factory crimp dies. In fact I still always do this for cartridges I plan to use for hunting. Early in my reloading career I had some hunting rounds where the bullets were pushing into the case.

I found that crimping hurt the accuracy but only very slightly it also did increase velocity. In both .223 and .270 at 200 yards I found the 200 yard groups slightly larger and noticeably higher (less drop = faster) when crimped vs not crimped everthing else being equal.

Two cautions though.

1. Crimping WILL increase pressure so start with a low powder charge again and work your way back up to an optimal velocity/pressure/accuracy range.

2. Crimping will shorten the life of your brass. Simple really more strain = more strain hardening = sooner splitting at the neck. Really not a big deal unless you're shooting some exotic cartridge where brass is hard to get.
 
Boomer said:
I am in the minority it seems, but I have determined that accuracy can be improved by crimping bullets that have a cannelure or crimping groove. Crimping uniforms round to round bullet pull weight, and accuracy is the bi-product of uniformity.

Some bullets with cannelures shoot very accurately. The Nosler Ballistic Tip is a case in point, as these bullets produce exceptional accuracy for a hunting bullet. Accuracy is dependent on uniformity and balance. If the bullet has an acceptable weight to length ratio, a uniform jacket thickness, and no voids in the lead core so the center of gravity coincides with the dimensional center, the bullet should produce good accuracy, irrespective of the presence of a cannelure.
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ballistic_tip_hunting_bullet.jpg
 
If you want to seat your bullet out to the lands for better accuracy, then crimp grooves are generally in the wrong place. That is where the Lee Factory crimp die shines.

No need to crimp for bolt guns unless it affects your accuracy for the better, or you suffer bullet movement due to recoil of course.
 
John, don't you think that crimping a non-canelured bullet will deform the bullet and detrimentally effect accuracy? I know Lee claims otherwise, but that doesn't make sence to me. Should I choose such a no-caneluredbullet I won't crimp, but would attempt to seat out to the lands provided it is long enough. In such cases I also prefer to have at least one caliber length of bullet shank in the neck of the cartridge, although some consider this too much with small bores with longish leads.
 
Boomer said:
John, don't you think that crimping a non-canelured bullet will deform the bullet and detrimentally effect accuracy? I know Lee claims otherwise, but that doesn't make sence to me. Should I choose such a no-caneluredbullet I won't crimp, but would attempt to seat out to the lands provided it is long enough. In such cases I also prefer to have at least one caliber length of bullet shank in the neck of the cartridge, although some consider this too much with small bores with longish leads.
Click to expand...

Anybody ever dissect a lee crimped non-cannelured bullet? Are they deformed more that what the rifling imparts on the bullet as it passes through the bore? Doesn't the bullet suffer the same deformity as the canelure is applied on a factory bullet?

Never gave it much thought before.....
 
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