i have about 99 105gn's left from one lot # that measure BTO .566. The new lot # i have measure .644, if i seat the new lot # to the same as i did with the .544 lot will it still shoot as good? or will i have to go through the whole seating depth process again with the new lot#?
may seem like a dumb question, but
- Thread starter michaeljp65
- Start date
DShortt
Gold $$ Contributor
I have my suspicions, but you'll never know until you try.
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If you can get the same "seating depth". . . that being how far down the base of the bullet is from the mouth of the case, it very likely will work just fine with the same powder/load. At least, that's been my experience with my .308. The other factor that'll have some effect is the difference in the bearing surface, which with that much difference in BTO, it's likely to have a significant difference in the length of the bearing surface. If so, you might need to make some adjustment with your powder or seating depth.
thanks for the replies gents. Ill load 5 same as the originals and see how it goes and using the chrono to see if im anywhere near the fps i was getting, then adjust seating or powder one at a time and see if it makes a difference.
Try the same base to ogive dimensions. It is generally quite close, but you may have to adjust the seating depth a few thou one way or the other.
ELR LVR
Silver $$ Contributor
^^^this
if your seating depth actually was measured in the correct spot on the Ogive
@michaeljp65 There are no dumb questions except the one that's not asked!
There are as many dumb questions as there are dumb answers.
They shouldn't be asked until they're not dumb.
That said, I think OP's question is good.
I doubt 10thou bearing/base seating depth change will matter to the load.
His CBTO will still be where he puts it.
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Please let us know what you find out. I for one would be interested to hear how it all shakes out.
Maybe the asker doesn't know that it's a dumb question which is why they asked in the first place.
The question maybe dumb to you!
CF Junkie
Gold $$ Contributor
Bullet length change in different lots is not as rare as one might think.
I measure every new lot of every bullet weight for every bullet brand I buy.
Most vary by a few thousandths and that amount of change has do to which forming machine the bullet was formed by or how old the dies were.
That amount of change will probably not be visible in your results.
But occasionally, the manufacturer changes bullet shapes to improve BC or some other charactistic, and the changes are much more significant.
Your change of 100 thousandths is very significant and you need to consider it as a totally different bullet.
I would also expect that the change in bullet length also may have changed the base to ogive measurement and probably also changed the ogive to tip measurement. Newer bullet designs with the same bullet weight usually increase the ogive to tip measurement and add a longer boat tail.
My experience says it will change the load approach considerably. You basically have a totally different bullet.
Changing seating depth will change velocity with the same power load and a longer boat tail will reduce the amount of bullet shank that can be touching the cartridge neck.
With the newly designed high BC bullets with shorter bullet base to ogives and longer boat tails, I have to monitor how much bullet shank is actually touching the neck while I attempt to keep jump close to the barrel's optimum jump distance, because if the amount of bullet body (shank) touching the cartridge neck becomes too small, you can't maintain neck tension consistency and accuracy diminishes.
I measure every new lot of every bullet weight for every bullet brand I buy.
Most vary by a few thousandths and that amount of change has do to which forming machine the bullet was formed by or how old the dies were.
That amount of change will probably not be visible in your results.
But occasionally, the manufacturer changes bullet shapes to improve BC or some other charactistic, and the changes are much more significant.
Your change of 100 thousandths is very significant and you need to consider it as a totally different bullet.
I would also expect that the change in bullet length also may have changed the base to ogive measurement and probably also changed the ogive to tip measurement. Newer bullet designs with the same bullet weight usually increase the ogive to tip measurement and add a longer boat tail.
My experience says it will change the load approach considerably. You basically have a totally different bullet.
Changing seating depth will change velocity with the same power load and a longer boat tail will reduce the amount of bullet shank that can be touching the cartridge neck.
With the newly designed high BC bullets with shorter bullet base to ogives and longer boat tails, I have to monitor how much bullet shank is actually touching the neck while I attempt to keep jump close to the barrel's optimum jump distance, because if the amount of bullet body (shank) touching the cartridge neck becomes too small, you can't maintain neck tension consistency and accuracy diminishes.
64Rambler
Gold $$ Contributor
With Berger 105s, I've been lucky once with a lot change and seating depth was spot on for the previous lot, but otherwise I had to find the new sweet spot, but the old spot was a great starting point.
It's easy to flame people. Show some respect . We all have different kinds of experience reloading, target shooting and hunting. A few questions are dumb but most people ask because they are trying to learn. I try to just ignore some replies and pretend I never saw them instead of flaming guys. I did jump on someone yesterday because he had no idea what he was talking about when he tried to correct me.
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