Anyone know why this happens?

[44Blam]

Occasionally, I get one of these:
271905

The crimp just opens up.

I'm reloading these on a Lee reloader, Fiocci hulls with the 7mm pastic base, RXP12 1-1/8 oz wad, a 0.07" card and 1 1/8oz of #4 birdshot on top of about 26 grain of herco.

[Bloodman14]

Basically, the hull is too full. I loaded hundreds of rounds for trap and skeet years ago, using Remington Black and Green hulls and Claybuster wads. Had that happen occasionally, using an old MEC semi-progressive press. Check your shot measure, or load 1 oz. of shot using 1 1/8 oz. data. Solved it for me, and you get a touch more velocity.

[44Blam]

Basically, the hull is too full. I loaded hundreds of rounds for trap and skeet years ago, using Remington Black and Green hulls and Claybuster wads. Had that happen occasionally, using an old MEC semi-progressive press. Check your shot measure, or load 1 oz. of shot using 1 1/8 oz. data. Solved it for me, and you get a touch more velocity.

I'll try this. I made 100 on Wednesday, shot 75 today in a match and found this one little bugger when putting everything up...

[la5676]

Yup, too much stuffing in the cavity. Stack height should be just below the folds of the crimp. I crimp mine pretty tight, get the normal dime depth and bevel the top pretty hard locking the crimp. That shell didn't look like it had any crimp depth at all to it.

[Hogtamer]

1 out of 75: that's a shell telling you Look! You did something wrong! Toomuch powder, an extra spacer, obviously something is different. Take it apart and see what it is.

[beagle]

It's a matter of matching the "load column" to the case. The internal dimensions are pretty critical on a case to get good crimps. The "book" recipes are designed to give a good crimp with a specific set of components. Any variation in the recipe or the failure to seat wads correctly and you get that result. Back when we used card and fiber wads, you could split wads and a specific wad pressure was stated for a specific load. Now, I believe the recommendation is to seat the plastic wad firmly on the powder.
In some loads, there's not much wiggle room in the recipe and a charge bar throwing light or heavy or a shot bar throwing light or heavy or different wad seating pressure can cause the "poochies" as I call them or a dished crimp. Just a matter of checking things to see why you're using too much space in the case. Also, shot bridging in the shot drop tube can cause this. I check the level before going to the crimp form station. If it looks too high or low, I discard in a container and re-drop./beagle

[dverna]

I suspect the rest of your shells were not very good either.

Using a card is a red flag for me. Very few published loads require a card if using the proper wad. Another red flag is using #4 shot in a match. Not allowed in trap or skeet so ???

I have never had a published load not crimp properly....so it is curious. Shotguns have a lot less “forgiveness” than a rifle or pistol so please do not experiment with loads. Wads are cheap. Use the proper data.

[rancher1913]

might try one of the spin crimpers, kind of a cross between a roll crimper and a fold crimper, it makes a nice tight clean fold.

[Bloodman14]

Internal hull capacities can differ as well. Learned this early on; had a 'backyard' range incident when my brother touched off a shell in my Winchester 1200. The shell had 'crushed' just slightly, and I thought nothing of it. He fired, the gun's report sounded bad, and I did some investigating. Discovered a crack in the chamber from the extractor notch, 6 inches up the barrel! That's when I bought Lyman's Shotshell manual, and learned that the shell manufacturers use different hulls for different loads, though they may be the same color. I had been using Hogdon's reloading manual, without consulting any other, not thinking that the hulls from the same manufacturer would be different. Expensive lesson.

[44Blam]

I suspect the rest of your shells were not very good either.

Using a card is a red flag for me. Very few published loads require a card if using the proper wad. Another red flag is using #4 shot in a match. Not allowed in trap or skeet so ???

I have never had a published load not crimp properly....so it is curious. Shotguns have a lot less “forgiveness” than a rifle or pistol so please do not experiment with loads. Wads are cheap. Use the proper data.
You know, matching load data would be great - if we had the components/powder/etc. So, when we can't we go figure things our for ourselves. I've been shooting this load pretty consistently since I ran out of stuff and it shoots well.
I use a little nitro card because that holds all the powder down at the base, I found that a lot of wads will let some of the powder kind of migrate up into the column... I see this even in commercial loads. I'd rather hold that powder down and get a consistent burn.
Anyway, the match was a combat steel match - not a trap/skeet match.
It's just every once in a while I get one of these guys.

[tomme boy]

I used to take a 1/4" steel rod a heat it till it was red. Then stuck it against the center of the crimp like Winchester does on their hunting loads. I figured these are the ones I would not get back so I did not care.

Some of my steel shot loads would do this but I did not burn them. The day before I was going hunting I ran them in the crimper again just to make sure they had a firm crimp. Steel shot loads need that extra firm crimp.

I also noticed that just sometimes the case has a little different flexibility to it and will not hold a crimp. I am sure that was what you ran into was an oddball case if it was just one. If the components were correct anyway. Thats why I hand weigh the powder and shot in each case.

[rancher1913]

one other idea is to make sure the hulls are trimmed so all are exact in length, an everso slightly longer hull will have the fold be to tight and make it want to "back off". I was having a problem with fold crimps and this turned out to be the problem

[FullTang]

Sounds like the issue is that you're getting a bit of extra powder migration because you're using a wad that's optimized for tapered hulls in a straight hull (and a thin-walled hull at that.) I feel your pain, as I always hate to see powder migration, and I think it does decrease consistency in some loads. The over-powder wad is probably a bit of overkill, though, and you might look at one of Ajay's slug posts---he uses a little square of newspaper over the powder to bump up the diameter of the wad's powder cup. This adds almost nothing to the stack height, whereas your card adds a lot and may be a problem.

[Sig]

Stack height. 10lbs of stuff in a 5lb bag.

[44Blam]

Sounds like the issue is that you're getting a bit of extra powder migration because you're using a wad that's optimized for tapered hulls in a straight hull (and a thin-walled hull at that.) I feel your pain, as I always hate to see powder migration, and I think it does decrease consistency in some loads. The over-powder wad is probably a bit of overkill, though, and you might look at one of Ajay's slug posts---he uses a little square of newspaper over the powder to bump up the diameter of the wad's powder cup. This adds almost nothing to the stack height, whereas your card adds a lot and may be a problem.

Very interesting. I didn't have any issue without the little nitro card, but I did have powder migration. I'll load up a couple like this and just cary them around in my pocket for a couple days and see what happens. Thanks!

[Hogtamer]

use a wad for straight wall hulls like the Fed SO3 substitute fom claybuster. They are slightly wider at the base. The Rem wad fits the slightly tapered Rem hulls.