What's the MINIMUM C.O.L. for 308 Win?

[guns1869]

Hey guys,
Looking for your re-loading expertise! I'm trying to re-load .308 Win for my Armalite Super SASS and here's my problem: I know Max C.O.L. is 2.810. Factory cartridges appear to have a fairly consistent C.O.L. of about 2.785. When I seat my 150gr FMJ BT to that same C.O.L. (2.785), the cannelure sits a rediculous amount too high. When I seat the same bullet to the middle of the cannelure, the C.O.L. measures a measly 2.710. Is this acceptable? What is the minimum C.O.L. for 7.62x51/308 Win?
Ps: I intend to crimp lightly...
Thanks for your help!
Vr,
Pete L.

 

[fish30114]

Re: What's the MINIMUM C.O.L. for 308 Win?

You'll have no issue seating bullets far enough into the case to have the cannelure at the case mouth--that's where it is intended to be for crimping. Pay attention to whether or not you are compressing your powder charge--especially in a gas gun. When you are crimping, you will be better off seating the bullet deep enough to get the case mouth in the cannelure.

 

[guns1869]

Re: What's the MINIMUM C.O.L. for 308 Win?

Thanks Fish!
I can no longer hear the powder move around when I shake the case. How do I know if I've compressed the powder too much? This load is for an Armalite Super SASS (AR-10).
Pete L.

 

[BCP]

Re: What's the MINIMUM C.O.L. for 308 Win?

Seat to the cannelure. Also, buy a reloading book.

 

[guns1869]

Re: What's the MINIMUM C.O.L. for 308 Win?

Thanks. I've got several reloading books BCP. Yes, read them too.

 

[armymedic.2]

Re: What's the MINIMUM C.O.L. for 308 Win?

you can hear/feel the powder crunching as you seat a bullet if it is compressed a lot on a stick type powder.

 

[fish30114]

Re: What's the MINIMUM C.O.L. for 308 Win?

1869, what armymedic said. If you don't hear powder shaking about when you shake the cartridge, it may be SLIGHTLY compressed whis is OK, or at least you have good load density--meaning the case is mostly full with your selected powder type and charge. This is good.

Heck, shooting compressed loads is OK, it's just another variable, and your cartridge OAL can grow after you seat the bullet onto a compressed load--sometimes quite a bit actually, which is why I recommend staying away from compressed loads especially with a gas gun. In your manuals you will see loads listed, and usually footnooted somehow, stating that they are compressed. I personally will no shoot a compressed load intentionally, just too many powders to choose from--now, I may have a load or two that compress so slightly that I can't feel or hear it--and I can hear the powder crunch on ball powders too (just not as much as if it is a stick powder) but I do check my OAL's a few days after loading them, if it is a charge that I know, or suspect is compressed--I have been surprised more than once how much the bullet was forced back out of the case--even with 4k or more neck tension.

Listen for the crunch on the seating, and also note that if your load is well within min and max charge ranges, and since you are crimping, you will likely have NO issue.

Good Shooting!

 

[guns1869]

Re: What's the MINIMUM C.O.L. for 308 Win?

Medic and Fish, you guys rock. Thanks!
I checked and it's only slightly compressed. I'm seating to the cannelure which results between 2.700 and 2.715. The crimp is light and all seems well. Now I'll get to the range as see what I've got. I appreciate the time and help!
Vr,
Pete L.

 

[ChrisGarrett]

Re: What's the MINIMUM C.O.L. for 308 Win?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Guns1869</div><div class="ubbcode-body">Medic and Fish, you guys rock. Thanks!
I checked and it's only slightly compressed. I'm seating to the cannelure which results between 2.700 and 2.715. The crimp is light and all seems well. Now I'll get to the range as see what I've got. I appreciate the time and help!
Vr,
Pete L. </div></div>

Don't worry about the cannelure, as they can be placed all over the map, on any particular bullet.

I've seen Lapua seat their 155 Scenars to 2.785", which is short for typical 308 bullet weights.

If you're loading for a bolt gun, you don't need to crimp, so the cannelure is just a drag inducing mutilation, of a perfectly good bullet.

If you're loading for a gas gun, you might not need to crimp, depending on your sizing die and particular brand of brass, due to sufficient neck tension.

The deeper you seat a bullet, the less internal volume you'll have, creating more pressure with the same amount of powder, so start low and work up, whatever you do.

Chris

 

[guns1869]

Re: What's the MINIMUM C.O.L. for 308 Win?

Thanks a lot Chris. I appreciate the info and that's what I'll do.
Vr,
Pete