Beginner question- Cannelures

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mistahmojoryan

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Curious what the purpose of cannelures are when reloading.

For a beginner, would it be simpler to buy bullets with a cannelure and just seat them to the middle of the cannelure? If I use bullets without a cannelure, do I go by the max COL?

Hope that makes sense; thanks!
 
canelures annoy me. I always seat the bullet just off the lands of my gun, so the cannelure rarely is in the right spot for a crimp. At least for rifles. For pistols (and rifles where accuracy isn't so important), seat to the cannelure, crimp and shoot
 
Ok, so it might make a good reference point at first but eventually I'll probably have no use for them.

I'm looking forward to progressing and experimenting w/ seating depth but I haven't even made a round yet. :)
 
Hornady goes and wrecks perfectly good bullets by putting them in. (not really) They may help control jacket to core bond or effect bullet upset upon expansion.
 
bisonhd said:
Hornady goes and wrecks perfectly good bullets by putting them in. (not really) They may help control jacket to core bond or effect bullet upset upon expansion.
Click to expand...

Their interbond, vmax and amax do not have cannelures.
 
Once again I find that I am the lone voice of reason.:D

Cannulars provide a place to crimp the case to the bullet. Hunting bullets work better when they are crimped for 2 reasons. Firstly, the bullet should be crimped to ensure reliable feeding from a magazine of any type of firearm - including gas guns. Secondly, very seldom can a bullet be loaded long enough to contact the rifling and still be able to function in a magazine. Therefore, when ammunition is crimped, the pull weight of that bullet is more consistent from round to round which benefits accuracy.

Match bullets and varmint bullets do not have cannulars because it is expected that they will be seated to the optimum length to maximize accuracy, so the problem would be where to put it.
 
"...to ensure reliable feeding..." Nope. Crimping keeps the bullet in place. Nothing more. It's not required for feeding on anything but a .45 ACP, most lever actions and rifle ammo that has heavy recoil. Crimping is always detrimental to accuracy. However, if you use a cartridge that has heavy recoil, you just work up the load taking the crimp into consideration.
 
If you are firing a bottle neck cartridge in a gas gun, keeping the bullet in place ensures reliable feeding. If you are shooting a powerful cartridge in a bolt gun, a crimp stops the bullet from being driven back into the case - which not only ensures proper feeding, it also prevents a pressure spike due to decreased case volume.

The idea that crimping when done correctly is detrimental to accuracy is simply wrong. Match shooters seat their bullets into the rifling or very close to it to uniform the bullet pull weight. When a bullet is seated so that the round will function properly through a magazine, the only way to uniform the pull weight is to crimp the bullet into place. The result is good accuracy rather than so so accuracy. I crimp all my hunting ammo, and I get MOA accuracy.

If you crimp uncannulared bullets, you will probably deform the bullet, which is unwise. If you crimp a cannulared bullet to the extent that it deforms the bullet, you are doing it wrong. Seating and crimping the bullet in the same step is doing it wrong.

The proper way to crimp with a cannulared jacketed bullet using an RCBS style seating die is as follows; Put a cartridge which is ready for crimping in the shell holder and raise the ram to the top it it's stroke. Either remove the seating stem or adjust it so it cannot touch the bullet, and thread the seating die into the press until you feel firm contact with the cartridge. Lower the ram, adjust the die down about 1/8th of a turn. Raise the ram to crimp your cartridge. The die can now be locked in place, however I prefer to readjust it for each cartridge I crimp.

The bottom line is that loss of accuracy due to crimping is an old wives tail. Shortened case life due to crimping jacketed bullets is an old wives tail. There is no down side to crimping hunting ammo, and there are some benefits which can be realized from crimping.
 
In rifles with SAAMI spec chambers, crimping usually improves accuracy. Particularly when you can't seat to the lands. With tight-necked match chambers it's unnecessary as it just introduces another variable to the picture.

Bottom line, though, is the same as any other aspect of handloading. Try it and see. If it improves accuracy, then go for it. If you have a problem with bullets getting pushed back into the case under recoil, go for it - if you have a Marlin GG, you pretty much need to crimp
 
"Try it and see"...yeah, that seems to be the best answer to the whole "crimp or don't crimp" question.

Another question: For 300WM, should I be full length sizing or just neck sizing? I have a few hundred pieces of once fired brass; the Winchester and Frontier (Hornady) brass show minimal stretching (I'm referring to the little bulge above the belt). Remington, Federal and PMC brass all have larger bulges, FWIW. Any advice?
 
I wouldn't run out and buy neck dies. Just back your FL dies off a quarter to a half turn and go for the partial sizing. This will size the neck and some of the sized of the body, but should leave the shoulder alone. This is a good compromise for a hunting rifle as it should allow the round to chamber effortlessly while still providing much better case life than FL sizing will.
 
when i first started loading COL was a mystery to me, here is a very simple way to solve that. to figure out your guns max COL (to the rifling lands).

1. full length size 2 to 3 cases. don't prime or charge with powder.
2. cut a slot down the length of the neck with a dremel , hack saw..... only 1 slot on 1 side of the neck.
3.use steel wood or anything to remove burr inside and outside of the neck
4.put a little lube inside the neck
5.put your bullet of choice in the case neck, just far enough so the bullet doesn't fall out. adjust tension on the bullet by squeezing the neck tighter or open the slot to loosen. you want it just tight enough to be able to slide the bullet in and out by hand with a little effort.
6.chamber round, bullet ogive will hit the lands and push back into the case.
7.carefully remove round, measure COL with caliper.

if bullet gets stuck in the throat push it out with a cleaning rod and tighted neck tension.

8.chamber the round 4 or 5 times, use different bullets and cases and average the COL. plastic tip bullets will usually be within .010. its not bench rest accuracy, but more than good enough for hunting and informal target.

once you get your COL to the lands subtract .030" for 6mm and larger and .015 for smaller than 6mm. as a guide line, you may have to adjust it to fit in the magazine. remember the shell you are measuring with will be to the rifling lande, you should seat deeper to reduce the chance of pressure spikes.
 
There is a world of difference between hunting ammo and match ammo. When you assemble hunting ammo, functioning trumps accuracy. You must choose a bullet with predictable terminal performance, in a shape which is appropriate for the range you anticipate shooting, and load that bullet to a velocity which is within that bullet's design limitations. The cartridges must feed easily through the magazine, and must chamber without undue effort. The rifle must fire every time you press the trigger. Your choice of primer, powder, powder charge, and OAL must be made with reliable functioning as the main criteria. Compressed loads which can push bullets out over time resulting in difficult chambering should be avoided. Neither can you risk seating bullets long only to have the bullet stick in the throat of the chamber and dump powder into your action when you attempt to unload. If your cartridge fails any where down the line it could cost you your animal. If you are hunting something which is scratchy or nasty you could have bigger problems.

Match ammo must be made with every effort to minimize tolarances between cartridges. Cases need to be painstakingly prepped to so they are clones of one another. OAL is critical to achieve the optimal distance from the ogive of the bullet to the rifling. Bullets must be seated as straight as the limitations of one's equipment allow. Primers which create a suitable flame for ignition should be chosen over those which are unnecessarily disruptive. Powder must be chosen within specific burning rates closely reflecting the cartridge size and bullet weight.

When we try to make our hunting ammo too accurate or make our match ammo too powerful, we create problems for ourselves.
 
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