300 Blackout converted LC brass necks too thick

[popper]

BO chamber neck is 0.335 max. I check all rnds for neck greater than 0.330, pull anything over sized. Get an outside neck turning tool, Elec drill with large chuck, put base in chuck and hold the turn tool - goes fast. I strive for 0.011-0.012 neck wall thickness and outside turning will uniform wall thickness - inside reaming doesn't. I can turn 100 or so before I get tired and it only is done once per case.

[Hardcast]

It seems my thread has split into 2 separate threads. If that is my fault, I apologize, but I do not know how it happened. Just measured several 300 Blackout cases.

Factory 208 grain factory round, also loaded in LC brass: neck diameter .331"- chambers fine
"" "" "" fired case: neck thickness .014-.015"

Converted LC brass :neck thickness .016-.018"
Converted LC brass loaded round
with Sierra 220 grain RN soft point :neck diameter .336"- will not chamber
Converted LC brass loaded with coated cast boolit :neck diameter .337" -will not chamber

The converted brass necks measure .324" OD before loading

Looks like I would need to outside neck trim several thousandths off of each case to use these.

Tried to post a pic but this site does not upload images very well.




IMG_0902.jpg

[Hardcast]

Forster does make an outside case turner https://www.forsterproducts.com/prod...e-neck-turner/
I have one and it works very easily and does not take long to outside turn necks. Can also get a power adapter to use a handheld drill or power screwdriver so you do not need to wear yourself out with the hand cranks, both well worth the money.

$59.00, plus shipping I assume, and it is out of stock. Already spent close to $30 for the inside reamer. This is ridiculous. I would be spending more than the cost of the 500 pieces of brass just to make them work.

[Hardcast]

BK7saum, I was intending to post a Want To Trade ad here on the forum. I have plenty of new Starline .45 Colt brass to trade. Waiting to do some more experimenting first. Thanks for the offer.

[Hardcast]

I have cut/formed and trimmed hundreds of LC brass for 300BO and have not had any issues, is there a lip on the brass from the sizing/trimming process?

No lip.

[brstevns]

$59.00, plus shipping I assume, and it is out of stock. Already spent close to $30 for the inside reamer. This is ridiculous. I would be spending more than the cost of the 500 pieces of brass just to make them work.

Know what you are saying, I bought mine many a year ago when the price was less than half what they are now.
Sometimes you can find them on ebay. They do come in handy for other cals as well. I got mine to help my Father to make 243 win from 308 win. I have also loaded it to a cousin to make 257 Roberts from 30-06 brass.

[brstevns]

Just a thought, but is the brass the correct length for 300 blk?
No longer than 1.368

[Hardcast]

[QUOTE=brstevns;5051529]Just a thought, but is the brass the correct length for 300 blk?
No longer than 1.368[/QUOTE

1.358-1.360"

[brstevns]

OK that should not be the problem,

[Alferd Packer]

Try paper patch?

[Lloyd Smale]

I have 4 bo rifles. 3 ars and a ruger american. Two feed anything one ar works a 100 percent if i use 308 bullets and my american is still stiff to close on 308s and probably could stand some outside neck turning too. Im not to conserned about that one because im thinking on opening it up to 300 harm'r but anymore all my 300 bo cast is sized to 308 and i found there every bit as accurate as when i was sizing to 309.

[tbpollard]

I have used allot of LC brass for 300 BO, I've never had an issue with neck thickness, but I do put a good bit of flare on the neck.

[popper]

Neck SPEC is 334 BUT chambers are all over the place. Cut down brass the case wall is now the neck and could easily be thicker as well as non-uniform. Mic the neck of a fired case from your gun and that is max! Seat your bullet and measure OD of neck. If larger than previous, won't fit! If using jacketed, probably don't need to turn necks.

[tbpollard]

And for clarification, I'm shooting cast 230gr subs and 145 gr supers.

[popper]

I have a tight custom barrel carbine but the others are very loose. Mostly shoot cast. I use the RCBS neck tool.