Necking down brass for wildcat

[mechengr]

Ok I just wanted to confirm it was nothing basic.

I would also recommend paying attention to JE Custom. While I have done wildcatts and know more about the 6.8 AR15s than most he has likely done 10x case forming for every one I have done. i.e. he knows his stuff from everything I have seen him post on the forums over the yrs.

Honestly the issue you are having is minor. As he stated its likely hard brass at the case neck. You could switch brass going forward. As you already have what you have why not try a few seconds spinning the neck under a propane torch flame to fix it. You do not need to anneal it to ideal loading level just stress relieve the crystal slip joints in the brass structure of the necks. Its called the recovery phase of annealing. (IMO it likley what the low temp molten slat pot annealing kits are actually doing give temp and time vs typically foubd using torch or induction) Start out with a few seconds (3-4) in the flame spinning on a drill and go up or down in time till you find what allows you to finish the sizing.

Another suggestion for good brass is S&B its tough and might be hard but IMO to do this right no matter what annealing is in your future. In general its the closest I have found to my old early runs of SSA brass when Art Cox was still the owner. He was a great guy and super supportive and helping with testing etc donating ammo components piezo pressure test our barrels etc. Glad I had a large supply.

Another thing is if you turn the brass prior, then as you neck down, some of that neck becomes shoulder of the same thickness as the neck. That will reduce the likelihood of doughnuts forming as you have multiple loadings on it. You also will have less to finish turn and should make sixing down the necks easier with less snap back after coming out of the neck bushing.

The reason I asked if you had a barrel already chambered is you can do more to improve the case if you want.

But first what is your plan for this cartridge? What barrel length? What bullets are you planning? Paper punching varmint hunting what?

As your platform is ar-15 you are limited in COAL to 2.30 maybe another.01 but that's it with the roomiest mags unless you notch them. So the bullets you plan can play into what ideally you may want to change. Not to mention how much freebore you have cut.

The AR feeding angle has no issues with sharp 40° shoulders etc. Heck, it can feed short super fat sharp shouldered WSSM cases no issue which most bolt actions have a seriously hard time with. So lots you can do here if you are game and it fits your goals.

I think there's a good chance the brass could be the root cause here so I've already gotten some Remington brass on order, should be here middle of next week. You make a good point though, I may try my hand at lightly annealing some of the Starline case mouths just to see how that works as well.

I did actually consider an even "wilder" cat, I ran across a cartridge called the 22 PDK which is a necked down and 30° improved 6.8 SPC case. It'll yield a hair more velocity than the 22x6.8 but requires custom dies and fire forming, so I decided not to go that route yet.

 

[The Hock]

Look for pbike257 on here and 6mmbr.com. He makes a sweet set of dies that are not cartridge dependent. He has a YouTube video demonstrating it. Using it might solve your issues.
His barrel vice and action wrenches also get great reviews.

 

[mechengr]

Look for pbike257 on here and 6mmbr.com. He makes a sweet set of dies that are not cartridge dependent. He has a YouTube video demonstrating it. Using it might solve your issues.
His barrel vice and action wrenches also get great reviews.

Just looked up his thread on 6mmbr and wow those dies look high quality! The general concept doesn't really seem much different than what I'm attempting with a bushing sizer die, but if the softer Remington brass doesn't work for me I'll definitely be getting in contact with him about ordering the dies I need. There seems to be pretty generous taper on the mouth of his bushings

 

[The Hock]

Good deal! I really got interested when I was contemplating a 270-8x68 (270 Booboo) on RWS brass. I love the brass because it's really tough but my experience was the same as yours. For now the project has been shelved...

 

[tim_w]

I think there's a good chance the brass could be the root cause here so I've already gotten some Remington brass on order, should be here middle of next week. You make a good point though, I may try my hand at lightly annealing some of the Starline case mouths just to see how that works as well.

I did actually consider an even "wilder" cat, I ran across a cartridge called the 22 PDK which is a necked down and 30° improved 6.8 SPC case. It'll yield a hair more velocity than the 22x6.8 but requires custom dies and fire forming, so I decided not to go that route yet.

Sound like a good plan. Watch out as wildcatting is addictive!! Its nice when no can make a case with the neck length that works for your bullets and a shoulder that helps keep turbulence in the case etc.

Take the 6.8 you could take 0.005 out of the taper. Shoulder to 37-40°. Adjust the neck shoulder junction to allow ideal location of the bullet of choice for 2.30 coal. Adjust throat so you are not a huge .100 jump but closer for better tuning.

The 6.8 base case would make an awesome base for a 100/200yd BR 22 and 6mm case. Its a short rimless 30-30 for all purposes and the first sub 0.200 agg was a wildcat off a 3030 that could be made much easier with a 6.8 and small primer like the old usa3030 cases. .01/inch taper 30 degree shoulder set back to equal ppc case vol. Keep a tad longer case neck. Lapua manf is the only thing to make it better.

 

[ILVTOHT]

I'm starting down the path of my first wildcat and need some help figuring out what's going wrong. I've decided to build a 22x6.8 in an AR for use as a coyote thumper. I made my first orders and started out by getting stuff to mock up dummy rounds for me to oogle at while I gather up the rest of the rifle parts over the next few months. Starline 6.8 SPC brass, a 6.8 SPC Redding Type-S bushing die and a bunch of bushings to progressively neck it down to 22 cal. I've got bushings in size .288, .280, .269, .260 and .250, I read somewhere that recommended a .010 step down in bushing size and those are the closest I could get for what was in stock at the time I ordered. The problem I'm having is that after two steps down, the case mouth flares out causing it to not be able to enter the next smaller bushing. All the coaxing I can give and it just crushes the shoulder instead of reducing the neck.

Here's the full progression of how it's going down:
1. I chamfered and deburred the case mouths prior to any work. Checked diameter along the full length of the neck and they're straight (no flare) when they come out of the bag. Also, case length is about .002 below book trim length
2. Setup the die to just touch the shoulder with ram at full extension. For this wildcat the shoulder doesn't have to move, only the neck gets reduced. Bushings are floated using the "rotate 1/16 off" trick the Redding instructions call for.
3. Lubricated the neck OD thoroughly with Hornady Unique and run the case through. The factory brass measures .299 outside neck diameter, so the first step down to .288 is 11 thou. Brass runs through smooth and easy. Case length grows by .001 and no measurable flare at this point.
4. Next up is a .280 bushing. This is the one that's giving me the issues. Lube case neck again and run it through, feels no different than the .288 bushing did but comes out having the case mouth flared. Case length grows by .003-.004 this time. Measured with calipers the mouth is flaring out about .003 from the rest of the neck
5. The .269 bushing does have a radius lead-in, but I have yet to get these flared case mouths to enter the bushing without completely crushing the case. Already ruined three cases trying to finagle it and don't want to ruin any more until I can get some advice on how to move forward

Any idea what causes this? I'm considering buying a .275 bushing to try and go a smaller step thinking maybe the flare will correct itself... Not sure if it make a difference, but all the bushings are LE Wilson except the .280 that's causing the issues is a Redding bushing. Could it be a bad bushing? Do I need to do any other brass prep between bushings? Everything I read about this cartridge said brass prep was easy as a few passes through a bushing die, no trimming necessary. Hope I can figure out a way to make that true!

My opinion... your overworking/overthinking it. Do the sizing in 2 steps. .277-.257, then .257-.224. I resize 30-06 up to 35 whelen in one step, and 30-06 down to 25-06 in one step. With no problem all the time.

 

[mechengr]

My opinion... your overworking/overthinking it. Do the sizing in 2 steps. .277-.257, then .257-.224. I resize 30-06 up to 35 whelen in one step, and 30-06 down to 25-06 in one step. With no problem all the time.

You make a solid argument.... I guess I took this route (using many bushings in ~.010 increments) solely based on threads I came across in some other forums written about making brass for this specific cartridge. I'll give this a try though with not so many steps, it's worth a shot! Thanks for the recommendation

 

[ILVTOHT]

You make a solid argument.... I guess I took this route (using many bushings in ~.010 increments) solely based on threads I came across in some other forums written about making brass for this specific cartridge. I'll give this a try though with not so many steps, it's worth a shot! Thanks for the recommendation

What your running into is... every time you run a case thru a die, (any die) the neck gets longer and harder(work hardened)... also when you neck down a case the neck gets longer and thicker... you "may" need to trim, and or turn the necks when your done sizing, it all depends on the chamber.

 

[J E Custom]

Am I missing something? I have read every post. Isn't the .224 Valkyrie a necked down 6.8 SPC? If so why would you be going to all this trouble to neck down to a known cartridge with brass available. Part of the reason you are crushing the shoulders is because as you neck down the neck the shoulder gets longer. I would think after each step down you would have to back the sizing die up a bit.

Here is a video of the difference that might help. the Valkyrie overall case length is 1.600. the 6.8 has a overall case length of 1.686 adding more case capacity.



J E CUSTOM

 

[mechengr]

Okay everyone, if you have an extra Moron-of-the-Month trophy lying around I'll give you my mailing address because I've probably got the nomination in the bag, no contest....

I know in an earlier post I had said the decapping rod was completely removed. Well in reality I had removed the expander, but left the rod. Guess I was thinking one thing and typing another... Anyway, the decapping rod was preventing the neck from being reduced any further and was the cause of the crushes necks. Going back and rereading the original post I found on making 22x6.8 brass he explicitly lists to make sure the expander rod that comes with the 6.8 bushing die is removed, total bone head move on my part.

I removed the decapping rod and had no further issues taking the neck down to 22. Feels good to have that part figured out. I even tried it in two steps as was recommended and that seemed to work just as well as the 5 smaller steps. Attached is the end result: original 6.8 SPC case, 22x6.8 dummy round loaded with Speer 55 TNT @ mag length, 223 Rem w/ 55 TNT @ mag length, and a 22-250 for reference

I did also realize however that I'll probably have to get a separate FL sizing die... Since the hole in the bushing die was originally cut for a 6.8 diameter neck, trying to use it to size the shoulder and body on a case that now has a 22 cal neck results in only the outside half the shoulder getting sized even with the bushing in place... I've read Hornady and Whidden will make custom full length dies based on fired brass, probably will go that route

 

[MNbogboy]

Looks great, glad you found the "quirk".

 

[tim_w]

We all have done things like that. Ask me why it was the first thing I asked....BTDT lol

Glad its all working ok now.

As you have not got the reamer do a search on 22 6.8 wildcats. There are a couple that were popular. Basically what I mentioned doing. One was 22PKD the other 22 Beast. The later is basically what we did early on in the 6.8 creation. With SB cases its right on the edge of 36gr h2o capacity. PU a 22 barrel and have it chambered for it.

Get the slightly oversized BAT barrel extension to ensure a tight heated fit to the receiver for best accuracy. Clean up/square the upper reciever face. I just lap it square. I would not go with anything shorter than rifle length gas port location.

Makes me want to finish my last couple AR wildcat builds I have going.

Good luck on your build.

 

[J E Custom]

Okay everyone, if you have an extra Moron-of-the-Month trophy lying around I'll give you my mailing address because I've probably got the nomination in the bag, no contest....

I know in an earlier post I had said the decapping rod was completely removed. Well in reality I had removed the expander, but left the rod. Guess I was thinking one thing and typing another... Anyway, the decapping rod was preventing the neck from being reduced any further and was the cause of the crushes necks. Going back and rereading the original post I found on making 22x6.8 brass he explicitly lists to make sure the expander rod that comes with the 6.8 bushing die is removed, total bone head move on my part.

I removed the decapping rod and had no further issues taking the neck down to 22. Feels good to have that part figured out. I even tried it in two steps as was recommended and that seemed to work just as well as the 5 smaller steps. Attached is the end result: original 6.8 SPC case, 22x6.8 dummy round loaded with Speer 55 TNT @ mag length, 223 Rem w/ 55 TNT @ mag length, and a 22-250 for reference

I did also realize however that I'll probably have to get a separate FL sizing die... Since the hole in the bushing die was originally cut for a 6.8 diameter neck, trying to use it to size the shoulder and body on a case that now has a 22 cal neck results in only the outside half the shoulder getting sized even with the bushing in place... I've read Hornady and Whidden will make custom full length dies based on fired brass, probably will go that route

Sounds like you have it figured out !!!
The results look great and we are interested in hearing how well it does. Keep us posted.

J E CUSTOM

 

[yorke-1]

It really seems like you're over thinking this. I'd just use a 6mm BR die to go down from 6.8 to 6mm, then run the brass into a 224 Valkyrie die held off the shell holder far enough that it only sized the neck. After that you can use your 6.8 SPC die with whichever bushing you'd like to get the neck tension you're looking for if you needed to. Your brass could be ready to load and fire in two press strokes.