Making .300 BLK Brass

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Definitely something to check. With my barrel and the LC 08 brass I used I am good to go, but with other barrels, who knows?

Good point. :)
 
There is a nice spring detent jig on IIRC the BLKout forum, can also be found on castboolits, will worth it if using the H/F saw.

I didn't like the way cut cases feed from casefeeder so I've just been doing all the sizing and trimming with the RT1200, didn't like milling a 1050 toolhead down but works slick and I've found I'd rather make 300BLK the process .223 brass

link to jig being used http://youtu.be/2rySmFSnk0U
 
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I like that. Very nice. I bet folks have a lot of neat ideas for doing .300 BLK brass out there.
 
What makes the cut off piece of brass shoot out like that?

Agh... I see. :)
 
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Wonder what blade he is using on that chop saw mine sure doesnt cut like that.

I ended up using the metal saw blade that came with the chop saw. I tried an abrasive cut off blade but it was slower than the steel blade. Also, the abrasive blade was consumed as it cut and life was fairly short.

The brass is softer than the blade and the thin walls

I also found that the blade lasts longer if you let it do the cutting as opposed to plunging the saw blade into the case. The plunge cuts work at first but dulls the blade.

At 1200-1300 cuts, my blade was pretty much shot but it was abused in part to determine its life. With proper use, it will last longer.
 
What makes the cut off piece of brass shoot out like that?
I am wondering that as well. It might be the detent ball. The 22 caliber mouth of the next case pushes the cut case so the detent ball has room to move. As the detent ball clears the rim, it may have enough snap to push the case out.

The spring for the detent ball is probably fairly stout to keep the case from spinning during cutting.
 
I counted out about 525+ cases and started cutting them again today. Shortly into it the aluminum gear that is run by the belt loosened up and the wheel started slipping. My old eyes told me there was a pin in the gear so I took the thing apart. Wrong, it was a set screw (Uses a 2MM Allen wrench), and I could have fixed it without taking it apart. *sigh*

Got that fixed up with a touch of blue Loctite for good measure. The spring that helps keep the saw blade rotated up was a bit of a PIA to put back on, but not too bad.

Back to cutting cases. After finishing all the cases, I deburred and chamfered them. I am tumbling them for an hour or so and will size them later.

Red is still keeping an eye on things.
 

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I can't wait to start making 300blk brass. I just got my Forster dies in yesterday. I ordered the Redding 300k form and trim die. Do y'all use that?
 
I am going to add some measurements on neck thickness and neck diameters of loaded rounds soon, but the bottom line is that with my chamber I have no need to ream the necks.

I'll go get those measurements again.
 
RP factory .300 BLK case:

10.0 to 11.3 thousandths at the neck.


LC 08 case converted to .300 BLK:

11.3 to 12.8 thousandths at the neck.



Loaded round with a .3105 123 Gr Z Max intended for 7.62X39:

I measured it at .3346 at the widest spot on the neck.

This chambers freely in my .300 BLK barrel.

.0113 + .0128 + .3105 = .334.6. Hey, it matched my actual measurement of the loaded round. This doesn't always come out just that close.

What are other folks getting as far as actual measurements of loaded rounds with converted brass? What neck thicknesses are y'all seeing on other years of LC brass, as well as other brands of brass?
 

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I cerrosafed my 300BLK chamber, .335". So I keep the neck at .334" or less. Safest to actually measure what your chamber needs. Helps minimize the bullet that gets pinched and blows the gun up.
 
With a .308 bullet I would be at around .332 to .3325 (Some .308 bullets are a bit over .308)

Perhaps I will get some cerrosafe and do that though, even though I know they are chambering easily.

Any one else know their chamber measurements, or have loaded round neck OD measurements on your converted cases?
 
SAMMI diameter for the neck on .300 BLK is .335 (+.002), so the neck walls would have to be an average over .012 to cause a problem. That is assuming a .3085 bullet. .0125 gives .333, which gives .001 all the way around. Tight, but safe. .3085 + .01225 + .01225 = .333 That Lee piece says max .334, which is even tighter.

Naturally you have to test this in your chamber, and I now have some cerrosafe on the way, but I have already proven to myself that my .3346 round using a .3105 bullet clears. (Perhaps my chambers neck is over .335) That easily gives me .001+ clearance with a .308 bullet vs that 7.62X39 bullet in this LC08 brass. I have fired some of these 123 Gr .3105 Z Max bullets with no more pressure signs on the cases or primers and virtually the same velocity as the similar .3085 125 Gr SST. These are not max loads! I am sure the tighter bullet would show more pressure eventually.


My question is what other neck wall thicknesses are people seeing on other brass converted to .300 BLK before reaming, if it is reamed?
 
Neck thickness on my reformed R-P 223 Remington cases average 0.0115" plus/minus 0.001". Necks were NOT reamed.

Neck thickness on R=P 300 BLK cases averaged 0.011"

I have only reformed a handful of 5.56 NATO cases but did not have to measure.
 
I made a cast of the forward part of the chamber today with the Cerrosafe. The neck has a slight taper. After cooling for an hour inside, just forward of the shoulder measured right at .3394 and then right at the end (forward of properly trimmed brass), it measures right at .338.

Wow, lots of room. No wonder I am having no problems with clearance. YMMV of course.

If I was making brass to sell commercially, I expect I would ream them to be sure, but for my use these will be fine as is. Even in a chamber with a .334 neck, a round that is .3326 (.0113 + .0128 + .3085 = .3326), or even .333 should be fine in any but an undersized chamber.

Other LC brass may be thicker, and that would definitely be pushing it. I wonder what other LC brass years measure out at after being converted.

The Cerrosafe description at Midway said:
It melts at a temperature just above M&M's
and that is pretty accurate. I melted a small portion of the Cerrosafe in an extra powder scale tray and poured it in the chamber through a cut off .06 case. Both held with Vise Grip pliers of course. The propane torch melted it it just like they said, nearly like M&Ms.

Oh yea, inside it was the cats supervising. Not much help actually. :)
 

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Yes, I have read numerous threads there. Looks like LC 5.56 has, in general, been OK, but some foreign cases have been too thick. Always pays to check things when forming cases, even with .300 BLK, which barely qualifies for case forming.

My first big clue I was OK, besides chambering an inert round, was a LC08 case fired round which would accept a bullet loosely in the neck.

Chambers are going to vary though, and it pays to check carefully. If my chamber had been .334, my non reamed brass necks would have been borderline OK.
 
Yes, I have read numerous threads there. Looks like LC 5.56 has, in general, been OK, but some foreign cases have been too thick. Always pays to check things when forming cases, even with .300 BLK, which barely qualifies for case forming.

Several years ago, I weighed about 500 of W-W cases and 500 of LC cases. I think the LC cases were late 90's vintage but I do not specifically remember.

The W-W cases were significantly heavier than the LC cases.

As Walkalong said, it pays to check .

Also, remember what they say about "assume".
 
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