crimpin' on the groove

[soldierbilly1]

One quick q, how far do you seat your bullet down if you intend to taper crimp? Is there a nice sweet spot we shoot for?
I find that if the case edge is a little low on the groove, all turns out well. If the case it too high, not so good.
I am using a 45 Lee bullet, the flat nose round point with my Kimber.
If I seat the bullet in too far, the round has trouble seating properly in my bullet gauge.

thanks fo any help.

billy boy

[jonp]

plunk test. forget your bullet gauge. Crimp it into the crimp groove with a light crimp. Take your kimber apart and drop the round into the barrel and see if the rim drops even or a little below. if it does then it should feed. I did not have a great deal of trouble with my 2 kimbers. far less than I have had with my kahr's. Just make sure to check the mouth with a caliper to make sure it is right.

[Tatume]

I'm not following this. Bullets for auto pistols should not have a crimp groove, and if they do you should avoid using it. If you crimp into a crimp groove there will be nothing on which the cartridge can headspace. Most 1911 pistols will "headspace" on the extractor just fine (including my Kimbers and Les Baers), but that's not how they were designed to operate.

[41 mag fan]

What are you seating them to to begin with?
That lee you have a picture of? I'm not familiar with it.
To taper crimp, theres a whole world of differences and preferences out there from various individuals. Some prefer to just remove the bell from the case, some prefer to crimp at a .469-.472.
IMHO, I think it's up to the individual and how and what his specific gun prefers, or cycle.
jonp has it correct on the plunk test. Every barrel is different or so it seems.
Tatume has it correct on auto bullets not having a crimp groove. At least I've never seen one.

Are you sure the crimp groove you're thinking of is not a tumble lube groove? Or a lube groove period? A picture would help out on this one immensley

[jonp]

Some lead boolits do. I just bought some from Montana Bullet for an XD that have a crimp groove. I use the groove as a seating depth guide and put a slight taper crimp on it. I don't roll crimp it so the boolit protrudes over the brass but just enough to get the mouth down to the correct diameter and leave the brass exposed to properly headspace on the mouth.
Sorry if I was not clear on this point.

[41 mag fan]

Some lead boolits do. I just bought some from Montana Bullet for an XD that have a crimp groove. I use the groove as a seating depth guide and put a slight taper crimp on it. I don't roll crimp it so the boolit protrudes over the brass but just enough to get the mouth down to the correct diameter and leave the brass exposed to properly headspace on the mouth.
Sorry if I was not clear on this point.

Thats interesting...I've never seen one with a crimp groove. All my 45acp molds don't have one. I'd like to see a pic of one if you don't mind putting one up.

[jonp]

Attachment 68710

The boolit is a Missouri Bullet Company IDP #4-XD 200gr RNFP .452
This looks like a crimp groove to me. The lube can be seen clearly beneath it. Am I wrong in this?

[soldierbilly1]

Sorry guys, shoulda been more clear. The boolit is a 452-200-RF; I believe it was made for the 45 Long Colt. they always worked well, until now. BTW, they look exactly like the gent's XD bullets.
billy
eta: jonp I believe you got it right!

In addition, I have some TL Lee boolits that are SWC's, OK, where do you recommend I crimp on these guys? the first microband? thanks for the help!

[35remington]

Given that the taper crimp is not designed to "dig" the case mouth into the bullet very much, as flush gets that job done too, there is no necessity for it to be "in" a groove. Anywhere that still allows the bullet to chamber in your pistol is correct.

[jonp]

Agreed but when I seat it to the edge of the groove it comes out just right for feeding so that is a good and easy length gauge for me.

[35remington]

Great......just so long as you know crimping in a groove with a taper crimp is not necessary.

[BD]

Actually, depending on how you have your die adjusted, the groove can defeat the purpose of the taper crimp. Auto loaders are taper crimped, (rather than roll crimped), for two reasons; to preserve the case mouth diameter for the cartridge to headspace on, and to prevent the boolit from being "set back" into the case when it contacts the feed ramp on the way into the chamber. Taper crimping in to the groove may require you to reduce the mouth diameter beyond the point where it will provide positive headspace in order to get it "dug in" enough to prevent boolit set back. You can check this out by using the "thunk" test for head space, and by pushing a loaded cartridge against a solid surface to see if the boolit can be set back into the case. The boolit in this case looks like the Lee 200 gr RNFP. For me the best OAL with that boolit put the case mouth, and crimp, on the full diameter band just shy of the crimp groove. YMMV
BD

[35remington]

Consult SAAMI specs for ID of the chamber stop shoulder to know what degree of "overcrimp" is needed to make the case mouth smaller than this dimension. It's around .455" or so, as I recall. Or just a tad larger than the bullet, which makes sense.

The degree of crimp needed to prevent bullet setback when using a lead bullet is much greater than most apply when speaking of taper crimps. The typical .470-.471" taper crimp that is applied won't do much. Jacketed bullet retention is not helped with any amount of taper crimp.