.300 BO & .308 Win boolit seating

I wanted to avoid this one, being a nub, but I have a few friends pushing me. Trying to tackle .300 Blackout, from AR platform.
I am using Lee C309-170-F and Lee C309-180-R molds. I am also working out of Lyman 51st Edition, Lyman AR Reloading Handbook 2nd Edition and Lyman Cast Boolit Handbook 4th Edition (which doesn’t even cover .300 Blackout )
They only have data for their Lyman cast boolits, in the .300 BO category, but my Lee’s are really really close. I have my data all laid out nice, for H335, as per these books. ATM, I am only really interested in supers, not subs.
I’m hanging up on the OAL’s. This seems to be my Achilles heel with necked boolits, so far. From a previous post, I learned a lot about the seating of CBs… but I’m still getting somewhat twisted.
If I set the OALs as per the similar Lyman boolits OALs, I don’t quite reach what appears to be the groove intended for the crimp. I would be in that first band.
Is that OK?
If I set it a little bit deeper, approximately 0.065” , the case gets a very nice taper crimp, right into that groove. What I do notice, is 1) I’m at a smaller OAL than what’s listed, and 2) the GC is just starting to enter case.
Is that OK?

IRONICALLY, or perhaps not, lol, I haz the exact same issue, with these exact same boolits, from exact same molds , while reloading .308 Win, with that same exact 0.065” short of cannilure groove.
Which is my best solution? To set at similar mold listed OAL, and have the cartridges look funny… or to go that extra 0.065” to reach the groove, and look right, risking the slight entrance of case ?

Personally, I really hope for the later, as the crimp is sweet, and I don’t want it to look like a googan winged it, but because I am a nub, I’m trying my very best, to go by the book, and hard numbers, to get it “correct”.

Thanks for any help…

Edit: I should add, that both the .300 BO & .308 Win dummies, that I made, drop into Lyman case guage, and fall out, like buttah, with the boolits set back, to groove.

Forget about the crimp groove. You can crimp anywhere with the Lee die. Set your OAL to reach the leade, or beginning of the rifling. Engraving a touch is good. Then make sure the OAL will fit through your action.
Rick

I thank you , sir

Engraving a touch is good -- nope seat just off touching, 10-20 thou. Else you may get jams. They are not fun. Forget the crimp groove. Proper neck tension (ID ~ 2 thou. less than bullet OD) and just flatten any flare you put on the case mouth.

Thank you

The 2 boolits you list may be tough to get to feed in a 300 BLK AR. Have you tried to run your dummies out of a magazine? Make up 15 or 20 of them and see how they stack. Do they pinch in on the magazine ribs and bind the stack?

H335 is too slow as well. Try something between H4198 and H110/Lil Gun for powder.

Yup, need 2400, 4227, 1680 for those loads. I run a 170gr about 1400 for fun/SD but a 145gr with H110 for 2k stuff. Pistol and carbine.

i use h110 for.300bo supers


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