I'm currently developing a 175 SMK load for my LMT 308. I am limited to mag length, so I loaded ten rounds to test for accuracy and velocity and used a RCBS competition die to seat the bullets to 2.800. Knowing that I would need to load more rounds, I left the seating set to that depth. The next evening I loaded some rounds only to find the seating die was now seating the bullets to 2.77. I did not touch the die or remove it from the press. Any ideas as to why this would happen? I was under the impression with this die that once I found where I wanted the bullet seated I would be able to "set it and forget it."
Competition seating die
- Thread starter afd77
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Re: Competition seating die
The die, once set, will remain constant. Did you remove it from the press after loading those ten rounds?
Also, was it screwed into the press tightly? I have seen times when a die will loosen either from the lock ring or the press.
Normally I would say, if slight difference, that it could be varying bullets but SMK should not vary that much.
The die, once set, will remain constant. Did you remove it from the press after loading those ten rounds?
Also, was it screwed into the press tightly? I have seen times when a die will loosen either from the lock ring or the press.
Normally I would say, if slight difference, that it could be varying bullets but SMK should not vary that much.
Re: Competition seating die
Did you lock the lock ring around the die? .030" is a lot of movement for not changing anything. Did you use the same lot of 175 SMK as the previous time?
Did you lock the lock ring around the die? .030" is a lot of movement for not changing anything. Did you use the same lot of 175 SMK as the previous time?
Re: Competition seating die
Did you sort your bullets with a comparitor? This is why more and more people are seating per the ogive and not C.O.A.L. not saying this is 100% your problem but if you are looking for precision ammo and you aren't already reloading this way, I would start.
Did you sort your bullets with a comparitor? This is why more and more people are seating per the ogive and not C.O.A.L. not saying this is 100% your problem but if you are looking for precision ammo and you aren't already reloading this way, I would start.
Re: Competition seating die
Same lot of bullets, dies is locked into the press tightly. I don't use a comparator, but .030" is enough of a difference that the round is visibly shorter than the others just holding them side by side. I have since removed the die and inspected it to make sure there wasn't debris built up or lodged in the die. I didn't see anything. My only thought would be temperature possibly causing things to expand/contract? I load in an uninsulated basement, but the temperature hasn't varied to the point that I would expect it to be that pronounced. This a guess at best. The die is in a T-7 turret press. I checked to make sure the turret head was not loose and it is good and tight.
Same lot of bullets, dies is locked into the press tightly. I don't use a comparator, but .030" is enough of a difference that the round is visibly shorter than the others just holding them side by side. I have since removed the die and inspected it to make sure there wasn't debris built up or lodged in the die. I didn't see anything. My only thought would be temperature possibly causing things to expand/contract? I load in an uninsulated basement, but the temperature hasn't varied to the point that I would expect it to be that pronounced. This a guess at best. The die is in a T-7 turret press. I checked to make sure the turret head was not loose and it is good and tight.
Re: Competition seating die
What about your brass prep? Did you change anything? Was the first batch on virgin brass, and the next on once-fired? The bullet can seat deeper/ shorter with different lubricities inside the case neck. This would be my guess as a source for your issue.
What about your brass prep? Did you change anything? Was the first batch on virgin brass, and the next on once-fired? The bullet can seat deeper/ shorter with different lubricities inside the case neck. This would be my guess as a source for your issue.
Re: Competition seating die
All Lapua brass, all new brass, all prepped exactly the same and then sorted by weight. This is why this is becoming quite a mystery to me. Anyone that's used these dies knows that the adjustment knob is stiff enough that it would take a pretty good bump to actually turn the knob enough to make that big of a difference. I also noted the hash it was set on after the first batch, and it was still there before seating the next. I'm hoping it's a one time anomaly, perhaps some debris that has since fallen out. Future loadings will tell. I appreciate the ideas.
All Lapua brass, all new brass, all prepped exactly the same and then sorted by weight. This is why this is becoming quite a mystery to me. Anyone that's used these dies knows that the adjustment knob is stiff enough that it would take a pretty good bump to actually turn the knob enough to make that big of a difference. I also noted the hash it was set on after the first batch, and it was still there before seating the next. I'm hoping it's a one time anomaly, perhaps some debris that has since fallen out. Future loadings will tell. I appreciate the ideas.
Re: Competition seating die
The next option is FM. Freakin' Magic! Or the calipers are reading different. Just dial out .030", and roll on.
The next option is FM. Freakin' Magic! Or the calipers are reading different. Just dial out .030", and roll on.
Re: Competition seating die
Magic is the only explanation I have. I am going to assume that I missed something, bumped something, loaded some rounds for different rifle in my sleep, or that gremlins hide in my basement and giggle at me after effing with my stuff. In all seriousness, it is not that big of deal. Like you said, adjust and move on. I'll keep worrying about only if it continues to happen. Thanks again for the help.
Magic is the only explanation I have. I am going to assume that I missed something, bumped something, loaded some rounds for different rifle in my sleep, or that gremlins hide in my basement and giggle at me after effing with my stuff. In all seriousness, it is not that big of deal. Like you said, adjust and move on. I'll keep worrying about only if it continues to happen. Thanks again for the help.
Re: Competition seating die
I suspect that the neck of the sized and prepped brass is loosening up after the initial sizing. That in itself can change the resistance to seating and thus the OAL. This is why Greg loads his ammo just before the match.
I suspect that the neck of the sized and prepped brass is loosening up after the initial sizing. That in itself can change the resistance to seating and thus the OAL. This is why Greg loads his ammo just before the match.
