Fixing 300 BLK brass thick neck wall?

[HankC]

I bought bulk converted 300 BLK brass from a forum private sale last year, did not know enough at the time and did not check headstamps. Now I pull the brass out and realize majority of the brass are known bad brass, CBC, PPU, RWS, PMC headstamps, for 300 BLK conversion due to thick wall. Loaded one and the neck diameter was .337, would not chamber at all. Is there any easy way to "thin" the brass neck? I know there is neck turning tool available, but they are not cheap and slow. If I put the brass back to sizing die, run a few times with the expander, would that stretch the neck thinner? I have 7.62x39 die with .311 expander, can I use the .311 expander to thin/stretch the neck?

If I end up scrap the brass, any good reliable source for 300 BLK brass? The bad part about this wall thickness thing is you won't know until loaded.

 

[rcmodel]

No easy fix.

Neck turning, or neck reaming is your only options.

No amount of sizing & expanding will ever make the necks thinner.

rc

 

[Dirtdgger]

Look up grumpa over at castboolits he will have what you need.

 

[HankC]

Is there a chamber reamer that I can open up the neck diameter to .340instead of the stupid .334 SAAMI? Don't know how they come up with the 334 spec for 300 BLK using 308 projectile, 308WIN SAAMI is .3435, if I can open up to .338 or .340, majority of the range pick-up brass will be fine to convert to 300 BLK. Most brass has wall thickness under .015".

 

[Reefinmike]

Lake city 556 brass is consistent quality brass that can be had for only a nickel a case. The annealing typically reaches down to where the new neck is formed.

 

[fguffey]

Is there any easy way to "thin" the brass neck?

Yes there was. I have two of the old ones that were made by R. Lee. Then there is the Reamer die by RCBS. The RCBS reamer die is a full length sizing die with a guide in the top of the die for a reamer. I have one for the 243; the cost is close to $90.00 plus an additional $70.00 for the reamer.

Yes it is possible to increase the diameter of the neck in the chamber. And it is possible to increase the length of the throat and it is possible to form cases with longer necks to increase case capacity etc..

Anyhow, when I ream the inside of the neck I use support for the case neck on the outside. A reloader called the other day asking if I still had a RL1200 Dillon case trimmer for sale. He said he was going to start forming Blackout cases etc.. I did not get involved.

F. Guffey

 

[HankC]

I contacted a guy who bought the same batch of brass and he said he also had chamber problem on that brass but he did not realize it was because of brass thickness and thought maybe sizing issue, he sized the brass a few times and chamber fine, now he load the brass OK. Another guy just sorted and scraped over 70% of the brass. I just contacted the guy who sold me the brass, he agrees to take the brass back. I will buy LC brass from now! If there is a chamber reamer to open up the neck diameter, I will be still interested, it will be more reliable. Finding out on loading rounds is a pain! Potential high pressure if chamber and fired is another concern.

 

[Walkalong]

If you have a Wilson trimmer all you need is a Wilson reamer and an expander to get the necks where you need them prior to reaming.


It can be done, but costs to get started.

 

[armarsh]

Is there a chamber reamer that I can open up the neck diameter to .340instead of the stupid .334 SAAMI? Don't know how they come up with the 334 spec for 300 BLK using 308 projectile, 308WIN SAAMI is .3435, if I can open up to .338 or .340, majority of the range pick-up brass will be fine to convert to 300 BLK. Most brass has wall thickness under .015".

Yep. http://pacifictoolandgauge.com/thro...eamer.html?search_query=neck+reamer&results=3

It shows 5 on hand but you would have to call them to see what diameter they have. You can specify any diameter you want but you might have to wait for a custom diameter.

 

[HankC]

Yep. http://pacifictoolandgauge.com/thro...eamer.html?search_query=neck+reamer&results=3

It shows 5 on hand but you would have to call them to see what diameter they have. You can specify any diameter you want but you might have to wait for a custom diameter.

This is just what I look for! Now, do you guys see any ill effect if opening up the neck diameter? To what diameter? I have built a few rifles and cut chambers with chamber finish reamer before.