Taper crimp

[Brad]

I went to set the 550 up to load some 45 ACP. The taper crimp die was a bit loose. I snugged it down and tried a few test cases. Crimp seemed a bit tight. Wait a second, the bullet rotates freely in the case! What the hell?
Tried another, same thing. Hmmmmmm

WAY too much crimp. A seated bullet won't move but once crimped like this it will. Neck tension is all gone. You can see how much it sized down my bullet too.
I did some adjusting and got it where I wanted it. I hate playing with a mic to see what the crimp measure, got to be a better way.
Made a little gauge. One side has a .470- hole, the other a .467+ hole. One is a go, the other a no go.


Crimped round fits snug in the go, won't enter the no go. Tells me my crimp is in the .468-.469 range.

 

[fiver]

I thought 470 was the recommended 45 acp crimp?

I wouldn't really know I don't think I have ever measured a crimp.
I kinda go by eyeball and feel then drop it in the gun.

I know, I know, something else I do wrong.

 

[Rick]

What if your next lot of brass is thicker or thinner?

 

[Brad]

If it works then it is never wrong.
I measured a few where the bullet would spin and they were under .462.
I have seen numbers from 470 to 468, I figure this lets me get close to that upper end. This round will just start in the .470 hole. That tells me I am very close to .470, probably. 4695 or so.

 

[Brad]

What if your next lot of brass is thicker or thinner?

Then those bullets get a little more or a little less crimp, right?
Time will tell if I can notice a difference shooting offhand.

My 1911 shooting is largely plinking at 25 yards or less. I'm not sure if the precise amount of crimp makes a difference. What I want is ammo that is reliable and reasonably accurate. My goal was more to ensure I don't over crimp.

I found that a severe over crimp lets the bullet move in the case. It also sizes the bullet a bunch. I don't want a bullet to telescope and raise pressures.

 

[fiver]

lot of brass?
in 45 acp?
a lot of 45 brass is when both pockets are full.

 

[Brad]

This lot is what I bought once fired. Mixed headstamps. Lord knows how many firings on each case.

 

[Stonecrusher]

That first picture looks almost like a bottleneck 44-40 case. Is that just the picture ore are you just partial sizing the brass? If not, that is a serious taper crimp. Didn't think the dies would screw down far enough to do that.

 

[Ian]

Bill gave me a Lee TC die after all our previous discussions on the subject. It puts a nice, well, TAPER crimp in the mouth but it is fairly short, meaning only about 3/32" back from the case mouth when the mouth is crimped to .469" which is where I prefer them. Bill insists on .465" or so but that's for competition ammo using SWCs.

Your crimp die looks like it is resizing the whole "neck" of the case like a Lee FCD does and is killing the neck tension. This is BAD. The crimp should not affect the bullet tension at all, if it does either your expanding spud is too bit, bullets too small, sizing die isn't doing its job, or the crimp die is affecting the whole top half of the brass. I had a minor blow-up due to bullet setback one time (my fault for being a little over-zealous with soft bullets and oversized expanding spud and not checking bullet retention on every headstamp of the mixed bag of brass). Winchester cases seem to be the thinnest and ever since that blowup I segregate headstamps for the most part, and my mixed "blazing" brass is all of known tension properties.

 

[Brad]

That is a Hornady taper crimp. Brass was full length resized. And yes, it is a major league over crimp situation. That crimp is closer to 460, maybe less! Totally destroyed neck tension.

I would like a taper crimp that didn't touch the case except the last 1/32 or so like Ian mentioned. Squeeze the very top of the case mouth and leave the rest alone. Resizing the leading edge of the front band doesn't bother me as much as sizing down the middle and rear of the bullet.

 

[freebullet]

Don't care for taper crimp. Only have 1 because it came in the set. Seems to be even more fussy to setup for me. I've never found the need for it.

 

[Ian]

BTW, neat tool you made there. It's difficult to measure crimp at the case mouth and a gauge is a good way to tell for sure.

 

[Brad]

Ok Ian, you love a challenge. Near as I can tell the 45 ACP tapers .3°. If we assume, and I hate doing that, that the Hornady die tapers about triple that it is still well under 1°. Am I seeing this correctly?
What if I cut a die with an internal taper closer to 2°. I could have the taper I want at the case mouth but leave the majority of the body alone. Still not enough angle to be a roll crimp but a sharper angled taper.
If my math is correct, and trig is not a strong suit, my current die tapers 1.3°. 3° might be a better choice.

Certainly worth a shot.

 

[RicinYakima]

I'm not sure if the precise amount of crimp makes a difference.

Since I don't shoot Bullseye at 50 yards anymore, I will say that it doesn't.

 

[Ian]

Cabin fever much?

Ok, for your curiosity Brad I took a fired case and ran it way up into the fabulous Lee TC die to give an exaggerated taper that could be measured. Using a back light and machinist's scale for a straightedge I got a pretty solid idea of the internal angle of the die. Overlaid on a small protractor, I come up with 4° per side. Crimping the case mouth to .469" with a .4515" bullet installed only scuffs off about 1/32" of Sharpie mark back from the mouth. Crimping all the way down to .465" affects maybe 1/16" of the case back from the mouth. It's hard to measure but you get the idea that even when cramming them down to .456" at the mouth 1/16" isn't much of the bearing length of the bullet and the 4° angle won't pucker up the case at all. Hope that helps.

 

[Brad]

Ok, 4° will be trial number one.

Yes, cabin fever has hit. I don't hide it well, do I?

Now to see how long I need the die to be to work in the Dillon and take a lock ring.

Thanks Ian. I know that when it comes to math and drawings I can count on you.

 

[fiver]

I'm going back in the gun room and trim some more 308 brass...

 

[Ian]

I was vacuuming the carpet in mine. It's amazing how many primers the Dyson can find in the short-pile stuff when I can't find them with half the crew from CSI. So far I've managed to clean and organize the first three feet into the room since Friday night. 11 more feet to go! Before anyone says "Why would you put carpet in there?" all I can say is my MO is to pick something up, drop it, pick the cat hair off, drop it again, forget the cat hair, and then do whatever I was going to do with it. More than one nice rifle has fallen over on the floor and every time it happens I'm SO glad there's at least a little cushion there. 1/4" industrial fire-rated carpet put right down on the slab is a heck of a lot better than an epoxy finish if you suffer from Butterfinger Syndrome. Well, except for all the little bullet lube and grease stains.

 

[RicinYakima]

Yep, I use that rubber mat made for floors!

 

[fiver]

mine is carpeted too.
it come that way with the house and was a greyish color to begin with.
it's now grey with black spots.
it gets vacuumed pretty continuously but I have to do the brass with the little 3 gallon shop vac.
I hooked the vac up to the trimmer once and it was so loud I had to wear earmuffs.
I just took a box and cut the front out to go around the press the trimmer is mounted on and it mostly keeps the trimmings in one place.
so I just have to do a little 2x2 area on the floor after brushing off the bench.
I will have the PMC cases done tomorrow, and will start on the federal's, then the Remington's the day after, and so on.