Bullet Seating Depth with Cannelure

hiredgun

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I am new to reloading and have a question about the above. From the various reloading manuals it seems that the best accuracy is usually obtained with the bullets seating close to the rifling. I am loading hunting bullets with a cannelure (Hornady 140 SST's in 270). Does the cannelure effectively determine the seating depth or am I missing something? Thanks for any advice.
 
In a .270 I would seat the bullet just off the rifling and ignore the cannelure--just do not put much crimp (if any) on the bullet unless you are using a Lee factory crimp die. I have many rifles in which the cannelure sits well out of the case mouth. In heavy recoiling rifles with heavy bullets it is sometimes necessary to seat to the cannelure so a heavy roll crimp can be applied.

FWIW, 44Bore
 
Bullet seating

Thanks for the advice. I am tempted to seat a few bullets using the cannelure as a guide. Is there any great flaw to this? Later I might push the bullet foreard to be just off the fifling. Thanks again.
 
I totally ignore the cannelure when loading my .270, but I do eyeball it and use it as a guideline only to weed out anything that may be off lenght. If the one cannelure groove throws you off, I can't imagine what the 5 grooves in a Barnes TSX would do.:D
BTW, seating close to the rifling providing best accuracy is not always true with all rifles and all bullets. I have a Tikka that shoots clover leafs with 0.075" off lands. Some Weatherby's like them...oh, half a mile off the lands.
 
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If you're just getting into it, there is no shame in sticking with the cannelure. given all the other variables that more strongly effect accuracy in the reloading process, and in a hunting grade rifle. (Playing around with bullet weights/types is probably the biggest variable)
As a beginner, its important to develop consistency, and systematic load development c/w recordkeeping. For example, each round of a given batch should be loaded to the same length, whatever it is. Another newbie mistake is not paying attention to brass - each batch should be of the same type, preferably the same lot. (Brass internal volumes have a strong effect on performance.)
Once you get your methods down, then you can play with OAL. This requires some finesse - bear in mind that each rifle is different in the leade, so a survey of each rifle is needed to avoid problems. Also, I've encountered different ogive profiles between boxes of similar Hornady bullets - something one has to watch carefully if you're going in close to the lands. Over the years, I've set my limit to 40 thou, after trying to go down to about 10...
FWIW - I shoot Hornady product a lot, and find that the flat based SP's generally shoot better than their boat-tailled cousins. (I'm only shooting to 100y.) I attribute this to more easily achieved concentricity in a flat based bullet. The performancer loss due to drag is negligeable for all my applications, both hunting and target.
 
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