I have a 222AI that shoots like a house on fire. However, I have noticed that my straight 223 brass shortens during fire forming, and they don't always end up the same length. They can vary as much as .030. Is that normal? Seems odd to me.
223AI Fireforming
- Thread starter Campguy308
- Start date
Not unusual, but you can mitigate that some. Depends on how the chamber was set up. Ideally you’d have some crush fit between the virgin case and the chamber when in battery. This pins the neck down and all the case stretch comes from the shoulder and body. If there’s no crush fit, the stretch takes the path of least resistance and comes from the shoulder and neck. Imagine walking up to the side of your bed, nearer the head, and giving the comforter a tug. Where does the comforter move, more towards the head, or the foot of the bed? Without the neck pinned, it all comes from the top.
Most of them are pretty consistently short, but some come out long. I'm using virgin Lapua brass currently but have had the same problem with other brands. Sometimes I feel a crush fit, sometimes I dont. I am jamming the bullet into the lands for FF. So what should I do? Cut them all to the shortest length?
I would say the bullet jam is not helping you at all. You’re creating an air gap at the shoulder. Probably be better to seat normally (Jump) and let the firing pin thrust the whole cartridge forward when it smacks the primer. It might stabilize the variance amidst some cases in a crush and some not.
No, shouldered barrel chambered in AI from the beginning. I had 4 misfires out of 100 FF loads this weekend
Lapua brass is usually pretty close in headspace case to case. If some are crushing, the short ones can’t be far behind, so headspace is unlikely to be your issue. Can you measure the FTF cases? You have a softer primer you can use, like a non-magnum small primer? Are these FTF’s a new occurrence with this barrel?
FTFs have been all CCI450 and BR4. When this thing was first rebarreled from its stock 700 VLS form, I was using the stock firing pin and pin hole. I had pierced primers with softer primers, so I always used the harder primers. The FTF issue has always existed, albeit intermittent.
I just got the pin hole bushed, and have not tried the softer primers yet.
It's just frustrating to FF 100 Lapua cases and have them be all different lengths afterwards. Between the FTFs and the length issue, it's a PITA. If it didnt hammer so well, I'd rebarrel to straight 223.
I just got the pin hole bushed, and have not tried the softer primers yet.
It's just frustrating to FF 100 Lapua cases and have them be all different lengths afterwards. Between the FTFs and the length issue, it's a PITA. If it didnt hammer so well, I'd rebarrel to straight 223.
