Mushroomed case

Another day at the reload bench, another problem. I was building five shot groups for my .204. I got completely done with the job and I was setting up my new magnifying light to admire my work when I noticed about half of the completed rounds have a slight swell just below the neck. About .003 . I crimped all of these rounds 1/4 turn, and I did all the crimping after I installed the bullet, not in the same process. So at this point I'm not completely sure when the problem occured, the COAL is still the same as when I set the bullet, this I know because I check each one. This tells me that this happened during the install process, not the crimp.???? Does this mean that the neck is to small, or maybe the bullet was not set pefectly into the case? I'm using a boat tail bullet, so it seemed fairly simlpe. I guess my biggest question is what I can do with this brass. I was building these for test loads and don't feel they should be used for that, but what now can I do with the brass. They will still chamber, should I fire these as a hunting load, or can the brass be resized again without going through the firing process? Thanks Larry.

Relax. OOOMMMM. There, that's better. The necks are fine, the bullets are fine. Since OAL is the same, it must have happened at crimping, and because of where it is, you discovered the maximum possible crimp for your bullet/brass.
Use them for tests, they will give you useful data.
No safety issue as they will chamber, you slightly over crimped them, just enough to notice (and you have sharp eyes) but not enough to affect function. Back off your crimp die just a tad bit. Better still, get a Factory Crimp die. I doubt the slight difference in degree of crimp to eliminate the bulge would affect the accuracy, but you never know. If it likes a heavier crimp, the FC die can do that without distorting bullet/case ala roll crimp.

do your bullets actually have cannellures or a crimp ring?
you may not need to crimp your rounds unless for a semi-auto, or lever action.
for rifle loads the neck tension will suffice usually.
and don't be surprised if those actually shoot better then your others.
and never,never,ever. take your seconds into the field,or shoot for score with them either.

Thanks for the reply's. I think I may have mislead you as to where the wrinkle on the brass occured. It happened at the very end of the body before it starts to neck down. If you misunderstood where I was talking about it's because I'm stupid, and if you did understand and answered my question and I missed it, well......I'm.....you know. My apologies.

Ok, here we go. Since this happened at the end of the body and the COL is exactly the same as the undamaged cases, doesn't that mean that it happened before the bullet was pushed to it's final resting place. All lengths are the same. The reason I did the crimping in a seperate step was to eliminate this problem. The thought of inserting a bullet at the same time your crimping sounded like a good way to compress the case. I know this is probably the way most people perform this, but I have the extra time. I don't know for a fact when it happened because I did not inspect them after inserting the bullet, just after the job was completed. Another thing that concern's me is if this did happen during the loading process, the damaged cases are now shorter and recieved less of a crimp, no? Next time I load I will pay closer attention and figure out exactly when, but my biggest concern was what to do with this brass. Since the bullet will chamber I am not afraid to use them, (not for accurate loads), but if they can be resized without firing, I will disassemble them and start over. Nothing then will be lost but time and pride.

runfiverun, these bullets are completely smooth if you still want to know. And If you wouldn't mind explaining, I don't completely understand your last sentence. Thanks guy's.

you are buckling the shoulder.
you are trying to crimp the bullet and the case has no where to go [no cannelure]
and you are pushing straight down on the case.
[you really don't need to crimp these.]
but if you feel you do then back out the sizer untill you just feel a slight amount of pressure in your press handle.
crimps are measured in thousands of an inch, not in foot lbs.
if they will chamber fine you should be able to shoot out the wrinkles.

my final sentence means.
if you want to make your best shot everytime, you have to have the confidence in your bullets and equipment each time you pull the trigger.
think about it like this, if i was there and said. i bet you 100.00 i can hit closer to the bullseye at 300 yds then you...................which bullets would you rather have.

Sounds good. I will pay closer attention this time making sure to inspect the rounds after each step.
That was kind of my thinking on the damaged rounds also, just shoot them as a hunting load or some other non critical situation. Probably most of them would resize, but some might not resize accurately, then it would be inconsistent and I would not know it.
I didn't understand what you meant by seconds, so I was trying to read more into your last sentence. sentences. sentence than was there. :mrgreen: I bet you gave your L.A. teacher a head full of grey hair. :-D Merry Christmas

r5r is right on top of the situation, as usual. :)
Treat them as plinking/practice loads. It probably wouldn't hurt to anneal the cases before loading them again.
Personally, I wouldn't consider a hunting load a non-critical situation. There is a life involved and it needs to be ended quickly and cleanly, even if it's a rodent. Ethics. Paper doesn't feel a thing if the POI is an inch or two off from what you expected. In the field or in a match the added confidence of being sure where the bullet is going can be critical. When I miss, (and I do) I want to KNOW it was because I jerked the trigger or misread the wind, not because there is some doubt about the ammunition I loaded or the gun I'm firing. I want to be the biggest variable.

There is nothing at all wrong with crimping in a separate step. Many if not most of us do it, at least for some rounds. Your problem illustrates the downside of roll crimping, and it makes no difference if you do it in a separate step or all at once, you can still have problems. It is not usually a good idea to apply a roll crimp to a bullet with no cannelure as you found out. But, learn something the hard way and you learn it forever. Happily, there are other ways to crimp.

As mentioned, often you don't need to crimp unless the action demands it (lever, pump, semi, revolver, heavy recoil). When it is optional, I will often try some of the best load crimped and uncrimped to see if there is a difference. Sometimes it is a positive difference, sometimes a negative, but it usually makes some difference. Most of my bolt action and Contender rifle loads get no crimp at all, but a few specific loads for them do better crimped for some reason. I don't know why, but the groups are much better in those specific instances, and the same barrel with a different bullet/powder shoots much better uncrimped.

Taper crimps use a die with a gradual taper to impart a light crimp that helps to prevent telescoping during feeding. They are most often used with straightwall semiauto handgun cases that index on the case mouth, but some also use them for cast bullets in handgun and rifle cases.

Factory crimps use a collet that squeezes the top of the neck circumferentially with a horizontal force. This is very similar to what is used by the big ammo manufacturers, hence the name. They are less particular about case length variation (you don't need to keep adjusting them) and they have no problems with non-cannelured bullets. They do require a separate operation, but it is well worth the extra step. Overdoing it results in a bullet with a constriction around its middle and a case mouth worked more than necessary (which may shorten it life), but no damage to the shoulder of the case. The handgun FC dies have carbide rings at the bottoms to insure that the rounds will chamber even if the bullet is seated a bit cocked, etc. (that happens sometimes with shorter bullets).

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Originally Posted by versifier

Personally, I wouldn't consider a hunting load a non-critical situation. There is a life involved and it needs to be ended quickly and cleanly, even if it's a rodent. Ethics.

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Thanks for taking the time versifier, I too share you concern's here, I just chose poor wording. I was letting this tunnel vision I have right now with getting these loads as accurate as I am able, do the talking.

When you talk about the crimping, I assume that the off the shelf RCBS dies that I have perform the taper crimp. I plan to no longer crimp until I get this gun dialed in, then see what difference a crimp makes from there. My 30-378 on the other hand I feel requires a crimp and don't feel I need any data from a non crimped bullet. Even if I find that they shoot slightly better, I don't feel I should risk possible bullet movement in the field. Thanks again. Larry

No, your RCBS dies roll crimp. There is a shoulder in the die neck that forms the crimp. You can see it inside with a bright light. When the die is over adjusted the neck or shoulder collapses from the downward veritcal pressure as you saw.

The taper crimp applies pressure both vertically and horizontally. Depending on the actual angle of the taper, the vector is hopefully more horizontal than vertical. I do not own a rifle taper die, so I am not sure what happens to a bottleneck case when the die is overadjusted, but in a pistol die they make it difficult to impossible for the case to index on the rim - if you are lucky, the extractor can still hold the case well enough for the firing pin to strike tthe primer, but it's an iffy thing and shows itself as erratic ignition with the misfires showing minor or no firing pin strikes on the primers.

I normally wouldn't bother crimping a .204, but I would try five crimped rounds after an acceptable load is worked up to see what difference it makes. There should be sufficient neck tension to hold the bullets in place against the minimal recoil the round produces. (If there isn't, the bullets are too small, the expander ball in the sizing die is too big or the neck of the sizer has too great a diameter.) For instance, I don't crimp jacketed bullet loads in .22-250 or .308 rounds for my bolt actions - their recoil levels do not make it necessary, their neck tensions are sufficient to keep the bullets in place during feeding/under recoil, and neither showed any positive benefit when I crimped them experimentally. I do crimp cast .308 loads however as it does have a very positive effect on group size (possibly due to improved ignition).

I would definitely be crimping a .30-.378 too. And if possible I would likely be trying to find someone else's shoulder to use for much of the bench work. :mrgreen: Not exactly my idea of a friendly plinking round, but I have heard a lot of positive things about it as a long range large game round.

balzout
i am glad you come and ask questions here.
you need to look around the net some, like at dillons website and forsters,,etc
what this will do for you is let you see the tools out there and then you can see what is available.
you will also get a better understanding of what the tools you have will do.
and what they won't do.
some of this stuff versifier and I am able to answer just because....well.... we bent, broke, mangeled. stuck,oopsied and other words.... equipment, brass, bullets, dies, stocks, blueing. recoil pads.

i for one wish i was able to ask questions from some one who had already done this.
so keep asking and i [and i will bet others] love to help, and confuse some too
as long as we can keep you on the safe track to getting the most out of whatever you are working on.

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Originally Posted by runfiverun

some of this stuff versifier and I am able to answer just because....well.... we bent, broke, mangeled. stuck,oopsied and other words.... equipment, brass, bullets, dies, stocks, blueing. recoil pads.

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:mrgreen: :rolleyes: ;) Truth is where you find it.

R5R and Versifier have the problem nailed for you.....its all in the crimping.

Just be aware that with a roll crimp (which is what I use) the case length is critical. Any variation in case length will cause more or less pressure during the crimping process. I would bet that your cases with the distortion were longer in length than those without the distortion. You might check your case lengths. You might also want to invest in a taper crimp die.