seating depth and cannelures?

[tdaughg]

im wondering how important it is to seat a bullet to the canelure? the problem is im loading .50 beowulf with sierra 350gr jhp's to the specs listed on alexander arms website. they say a oal of 2.13" but when i do that the mouth of the case almost touches the bottom of the cannelure, its not in the middle.

ive searched all over the place and some say that if theres a cannelure you have to seat the bullet to that depth others say it doesnt matter. my question to the pro's is should i just leave it at spec or seat the bullet a little lower? thanks.

[pisarski]

seat the bullet to the right oal the cannelure is not that big of a deal

[halifax]

As was said, the cannelure is not a big deal if OAL is important to you. If, however, you bought the bullets with the cannelure to take advantage of their intended purpose of holding the bullet more securely, then crimp it into the cannelure correctly. (May have to drop the charge slightly if you are at MAX.)

[rabagley]

(May have to drop the charge slightly if you are at MAX.)

Depending on how much the bullet moves to line up the cannelure with the case mouth and how much volume the case has, dropping the charge slightly may still be unsafe. With .50 BEO and the .05" change needed on the bullet pictured, there's enough case volume that "dropping it slightly" is probably exactly right.

But I would not assume that that's okay in most OAL reductions. For a lot of other bullet/cartridge combinations, I would go back to starting loads or even less. Even small OAL changes in most pistol cartridges can enormously change the pressure curve and blow up your gun if you're not careful.

And I'll add my voice to the chorus of answers in the thread: AA's load data do not expect you to use the cannelure. You can go either way and it doesn't matter a whole lot.

[tdaughg]

thanks for the help everyone. ive got 10 rounds done already with varying powder charges from really light right up to the max so ill just stick with them as until i get a good idea of how they perform. maybe on the next batch ill try to seat to the cannelure with a light load to see if its any different performance. either way the beowulf dies use a taper crimp instead of a roll crimp so i wont be getting a proper crimp on the cannelure anyways.

[JamesY]

You loaded 10rds total, each with different grains? Or did you mean you made 10 lots with each lot having different grains of powder?

[J-cat]

Cannelures are for revolver applications where you roll crimp into the cannelure to reduce the possibility of bullets pulling out of the case under recoil. This is not an issue in semi-auto applications, so you can load to whatever OAL, ignoring the cannelure alltogether.

[tdaughg]

You loaded 10rds total, each with different grains? Or did you mean you made 10 lots with each lot having different grains of powder?

sorry 10 round lots, 5 different weights so 50 rounds total. since the cannelure seems to be irrelevant ill leave them as is. im also to lazy to pull the bullets, re-weigh the charges, and then re-seat when theres no need to.

[joelogic]

Isnt this backwards. I thought the cannelure was for semi-auto guns so the bullet did not press back into the case during loading.

Cannelures are for revolver applications where you roll crimp into the cannelure to reduce the possibility of bullets pulling out of the case under recoil. This is not an issue in semi-auto applications, so you can load to whatever OAL, ignoring the cannelure alltogether.

[Nessal]

Yup just do it till is is the correct oal.

[J-cat]

No.

Cannelures do not prevent bullets from pressing back into the case. Cannelures are concave in profile. The case mouth is unable to catch the edge of the cannelure and slides right out of it when the bullet presses deeper into the case.

Semi-auto rounds rely on case tension to hold the bullet in place.