Please don't groan at another newbie question, but I gotta ask.

My .348 must be crimped, and firmly! I have already had an unpleasant experience with J$#^&&d bullets, with them slipping back into uncompressed Winchester factory loads. Some as far as almost out of sight! This was determined to be either a weak initial crimp or age-weakened crimps due to the 1950's production date of the ammo. I have since fixed this by recrimping with the Lee die.

Now as I get started with CB's, I would like a clear understanding of what crimping location flexibility I might have, should I wish to adjust OAL.

Must I limit my crimp location to a cast groove? Or can I locate my crimp ahead of the grooves, and if so, what works best? This assumes a BHN of at least 20.

If you crimp ahead of the grooves at the front of the top driving band you still run a risk of getting a bullet pushed down into the case. Got a .45-70 like that right now. I suspect I've had that happen during shooting without noticing it, as I've seen a few rounds jump up 100 FPS or so faster than the rest. Started seating my bullets a little farther out so I wasn't crimping on the front edge. There's got to be some lead ahead of the crimp. The Lee Factory Crimp Die doesn't care whether there's a groove under it or not, it'll crimp right into hardened lead or a bullet jacket. Haven't tried it on one of those solid copper bullets (and I'm not interested in those bullets, anyway.)

[ 11-30-2003, 23:17: Message edited by: NotRicochet ]

Brushbuster, One thing you did not mention is case tension. This is extremely important for straight wall cases. If the bullet goes in the case too easy and the brass does not have a tight hold on it, no amount of crimp will correct it. Shooting black powder with no case tension is fine and most BPCR shooters just seat by hand, but smokeless needs tension or the bullet blows out of the case before a good burn gets going. Bad for accuracy. In a lever gun you need both tension and crimp and you sure do not want to crimp in front of the first band as it will be driven back in the case in the magazine and that shell will raise pressures to an extreme amount.
You have to find a spot on the bullet where you can crimp and still feed the shells. Like the guys say, the Lee will crimp anywhere.
Anytime you make the seating depth of a bullet deeper you have to reduce the powder charge and work up again. It is dangerous to get a bullet too deep if you are shooting close to max loads. One that is driven all the way into a case can take your gun apart, please be careful.

Yeah, I know, the .348 has a shoulder, but in a lever action it should be treated as a straight case because of the tubular magazine. If this was a bolt gun, then it would not matter so much and the amount of tension needed would not be important and no crimp would be needed. Sorry I did not mention it on my first post.

Thanks for some good responses on this.

Because of my own experience, I have come to the conclusion that recoil forces in the tubular magazine are greater than any loading or handling strains placed on a crimp. No doubt this force increases in proportion as we approach maximum loads and place even greater demands upon the crimp.

I do realize that I am treading in dangerous waters when I even consider locating the crimp location in any other than that designated for a given bullet design, and that's what prompted my question.

If you would, please go to the NEI site http://www.neihandtools.com/catalog/frame.html
and look up the molds available for the .348 Winchester. It is the two heavy bullets that are of interest to me.

Mold #107 appears to me to have a good aerodynamic design with a large meplat but few grooves and therefore reduced bore contact. The crimp location is not well-defined, and the long Driving Band? (not clear on the terminology here) seems to provide crimp location choices, but without a forward shoulder to assist the crimp holding strength.

Mold #108 with its greater number of grooves and shorter Driving Band, would seem to restrict the crimp to the forward groove, with no flexibility in crimp location but a more positive crimp location.

Both these bullets were designed for the .348 Winchester, a powerful tubular magazine cartridge. Yet in regards to crimp holding consideration they appear to be quite different. I found this confusing, and my inclination would be to crimp deeply into the driving band on mold #107 (whose design I prefer) and hope this would compensate for the lack of a forward shoulder. Surely the large single groove of this design is for lube only, and to place the crimp here would severely limit the lube available. Am I misinterpreting something here?

Sorry about the double post?

I agree with your assessment about where to crimp with those two bullets.