Cast 300blk load ?

[clearcut]

In order to get a Lee CTL312-160-2R (sized to .309 gas checked) to chamber in my 300blk I'm ending up with a oal of 1.967 that leads to the question .The bullet sits .398 in to the case changing the case volume. The powder I will be using is IMR4227 the bullet with check and powder coat drop at 166.7 + - my Lee table has 15.8 grn. for168 grn. jacketed as a start load will this be a safe with the cast bullet ? It looks like it will be compressed .Any one got an answer?
Thanks CC

 

[Swampman]

I haven't actually used any IMR-4227 for supersonic BO loads, but I have used it a little in subs and for 7.62x39 supersonic loads.

IMR shows a range of 15.8 to 16.9 with a 168 grain Hornady BTHP.

They also show a C.O.A.L. of 2.230", were it me, I'd back off at least a half grain and probably .8 grain if running pistol gas

IMR-4227 isn't near as squirrelly as H-110 with low charge weights. The worst you're likely to see is a bunch of unburned powder and maybe a lack of functioning.

 

[Jesse Heywood]

I would determine how much powder will give a compressed charge when your bullet is seated. Then reduce 5-10% for a starting load, working up to your compressed load. In my experience, 4227 does best when compressed.

 

[LoonWulf]

Just checked this on quickloads. Its predicting that youll top out at around 16.4, but youll be at 110% of case capacity.....im using a bullet length of .998, and a case length of 1.367

 

[clearcut]

loonwulf so what is your oal

 

[LoonWulf]

Adjusted to match your measured depth of bullet in the case....like an idiot i forgot to add the resulting coal to my post and i wont be home till tomorrow night to do so.


*Edit* so after realizing that its easy math i come up with a coal of 1.967, same as what you were using.
I believe what i did was modify the bullet length in quickloads to give me a 1.967 coal, with your noted bullet shank seating depth. The bullet length listed in quickloads, i believe gave me a longer oal when seated to .398 shank depth.....

Also why the short coal? My ar mags could take 2.25+ and tended to feed the longer rounds better than the 1.9ish 110-125 rounds?