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Matt, are you able to stay above the donut?9 and .220
Matt, are you able to stay above the donut?
I just sent a 7 RSAUM dummy round to JGS and they say it was .230" FB. My barrel will be an 8.5-twist.
.230 at touch or some specified amount of jump?
I'm running a 28" Bartlein with 8 twist. When starting the build, I called Dave Kiff at PTG and told him I wanted to seat just above the neck/shoulder junction, to avoid the donut, with 180 Hybrids jumped .005 and he recommended a .218 freebore.
How does that relate to the OP’s question?
I assume they set it at touch. I set the bearing surface/boattail junction ~.070" ahead of the neck/shoulder junction on the dummy round I sent to them.
I assume they set it at touch. I set the bearing surface/boattail junction ~.070" ahead of the neck/shoulder junction on the dummy round I sent to them.
New to 284. I'm necking up 6.5-284 lapua. Could you explain the donut? I'm freebored at 220, and want to shoot the Berger 180VLD's or 180 Hybrids. Is this enough freebore? Bullet seems quite far down into case. Thanks!8.25 and 230, it is above the donut. Straight 284
the donut is a reduced inside neck dia. that forms @ the neck shoulder junction from brass flow . the problem is if a bullet is seated in this donut it increases outside dia. of that portion and can cause a crimping effect witch can be dangerous by creating extreme chamber pressure . this can be over come by proper free bore, and seating bullets in front of this area. be safe dave. also you will be ok with a 220 fb and 180s if you don't use a long jump,New to 284. I'm necking up 6.5-284 lapua. Could you explain the donut? I'm freebored at 220, and want to shoot the Berger 180VLD's or 180 Hybrids. Is this enough freebore? Bullet seems quite far down into case. Thanks!

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