309-150 mold , looks like I need to size.

[capt.hollis]

Got this mold for my 300 AAC blackout AR15 . Just for grins I worked up a load last night , and just decided to see if the bullet would at least chamber. That would be a noooo, lol. What are you guys sizing these bullets down to . I do have a thin coat of epoxy on the bullets , but I'm guessing this bullet needs to go through a 309 sizing die?
This is a 150 gr 30 cal.

[fredj338]

Did you measure it BEFORE you seated it? Most chambers, regardless of caliber, will tolerate 0.001"-0.002" larger bullet dia, depending on brass. So I would start @ 0.001" larger than groove dia. You might also check seating depth, The Ogive looks like ti could be causing chambering issues as well.

[capt.hollis]

Did you measure it BEFORE you seated it? Most chambers, regardless of caliber, will tolerate 0.001"-0.002" larger bullet dia, depending on brass. So I would start @ 0.001" larger than groove dia. You might also check seating depth, The Ogive looks like ti could be causing chambering issues as well.

No sir Fred I did not, I just went with a standard fmj bullet seating depth, and OAL ive been using. Im fixin to go measure this now, and I appreciate the info. This never crossed my mind. Im new to this cast bullet stuff.
Thanks again Fred.

[capt.hollis]

Did you measure it BEFORE you seated it? Most chambers, regardless of caliber, will tolerate 0.001"-0.002" larger bullet dia, depending on brass. So I would start @ 0.001" larger than groove dia. You might also check seating depth, The Ogive looks like ti could be causing chambering issues as well.

No sir Fred I did not, I just went with a standard fmj bullet seating depth, and OAL ive been using. Im fixin to go measure this now, and I appreciate the info. This never crossed my mind. Im new to this cast bullet stuff.
Thanks again Fred.

[Moonie]

You have seated that boolit out too far. Remember, in a semi-auto you do not have the caming action of a bolt and you must seat the boolit deep enough that full groove diameter bands do not hang up in the chamber throat. Try seating them to the crimp groove and do a plunk test with your upper. Put the cartridge in the chamber and with your thumb gently push the BCG till it clicks in. If you can't you have problems. You should be able to easily push the BCG home with just a little thumb pressure. Keep in mind that this will cause you to seat this boolit very short and can cause some feeding issues depending on your magazines. I had this trouble with the lee 170gr because the nose is so short and if loaded further out they wouldn't allow the BCG to lock.