Where’s the 12.7 Blackout?

[JoshPutman]

It would be sweet to see one of these rounds show up on Texas Plinking's 1000 yard challenge.

 

[cas6969]

I also bought yet another mold, 700gr flat nose to....

Ah, I thought I had a picture.

 

[MO Fugga]

Ah, I thought I had a picture.

View attachment 8424414

Makes me wanna dust off the ol 4-20

 

[dk17hmr]

This is what I did. Cut them at 2.100. That allowed seating a 690gr SA ball slug at the cannalure and plenty of room feeding through Rem 700 LA Mag after a few tweaks to the follower. Thought I was clever but just reinvented the wheel. As I remember Trailboss velocities were low so I went to Unique, 2400, VV340. All have a good sub spot but I do use a coffee filter "wad" to keep the powder against the primer. I see about a 200fps difference from Gordon's predictions. Will try VV110 next. Got sidetracked on a 250gr .338 slug in a 5.56 case feeding from a standard mag in an AR. Looks good so far. Attention span of a gnat.

Thank you,
MrSmith

My razorback is 2.375" I think. I use 50 Alaska dies. Sounds like your a little closer to 50 Alaskan.

I mostly shoot 500gr cast bullets from it. NOE has a 850gr mold I keep thinking about but for as much as I play with it the 500gr lee 50-70 bullet is good enough.

 

[45-90]

I don't think a Lapua-sized bolt face will work in an AR10.

If you have a lathe, they will absolutely work in an AR 10.
Just turn the case head to fit the standard .535" mag bolt face, and recut the extractor groove...done.
Rebated rim and it fits into an AR 10.

I machined some for AR 10 but saved the 510 whisper project for a bolt gun, and 3.7" long cartridges and turned this AR 10 .510 whisper project into a 338 Ruger Compact Magnum, and now have 18" AR 10 338 magnum.

 

[biffj]

Sorry Dogtown, I don't remember the company that made my trimmer. I got it from Sinclair and its gold anodized....I'll have a look tomorrow. I did make up a pilot for it so I can trim without resizing. It fits the case mouth after I run the expander into it. Works great with a battery powered drill.

I've built some AR10's in 338BR and they work great but I'm a little leery of opening up the bolt face for the larger case heads. I'm not that interested in the ARs anyway so haven't pushed it.

Frank

 

[45-90]

I use a Bridgeport mill, with lever collet closing fixture, set up with dead lenght collets, to trim to exact length.
Cut time, about one second to trim to length.

 

[45-90]

My 510 Whisper boltgun is done, in two days after... converting the AR 10 project to 338 RCM, and testing loads for it, it was a total sucess...running full power 338 RCM loads through a 18" barreled AR 10.
Barrel of the 510 Whisper is 25.75" to take full advantage of the light copper bullets available for supers.
I ain't gonna run a suppressor, the extra barrel weight will help with the recoil, and put the blast away from the shooter...kind of.
It was a bit more involved than a standard rifle build, of chambering, threading, etc. Bolt modifications, fitting the bolt, fitting the extractor, slight magazine mods to the 338 MDT Lapua mag 3.715" it feeds the long 750 Amax from the mag.
Gonna set up to make 100 or 200 cases. Made 10 cases just for fun, and a dummy cartridge to check feeding, and one modified for the Hornady case gauge.
Then on to load development.

 

[45-90]

Trim to exact length in the mill, with a dead length collet in a lever closing fixture.
Light ID deburr, in the lathe for neck turning.
trial and error working with the FL 510 Whisper die, to get it exact and Your rifles chamber.
Lube with Lee sizing lube, and run through die.
Check in homemade gauge with tbe reamer that made the rifles chamber
And you're done.

 

[45-90]

So I shot my 510 Whisper about 80 rds today.
Here's what I found, newer, 612 GR APIT pop on impact on every shot even with muzzle velocities down to 780 fps.
Totally fun to shoot, see the impact flash in the scope then the "pop" report.
Low velocity equals low recoil.
The all copper, Cutting Edge .510, 350 gr handgun bullet, was tried ...it was accurate and produced 2447 fps with 4700 ft/lbs of energy for a nice supersonic load.
Recoil was less than the supersonic 647/650 fmj bullet.
A fun day at the range.

 

[Rumlover]

If you want to go through all the aggravation to make 510 Whisper, go for it. If you want easy, get a 50 Alaskan. Starline makes brass.

 

[45-90]

I

If you want to go through all the aggravation to make 510 Whisper, go for it. If you want easy, get a 50 Alaskan. Starline makes brass.

Starline is always out of 50 Alaskan brass, made from 348 Win... that is rare too.
If one adds power accessories to the making of the .510 Whisper its easy..
Just made 100 of them a few days ago. Starting another one hundred today.
The rim of the 50 Alaskan is more for lever guns, which doesn't have the length in the action for long 650 gr plus bullets.
Mostly it's single shots proposition, with fast twist and throsted for 750 gr bullets. ...not boltguns with magazines.

For a single shot it would do the job with a fast twist and long throated barrel.
But the 50 Alaskan Starline brass is not readily available, I heard that Starline was 6 years behind in brass orders, filling the most common.
I got all the brass for making 510 Whisper for about 65 cents, for 600 Norma and $1 ea.for the 200 Lapua cheaper than Starline price for the 50 Alaskan.
But you can have your brass now, and if one adds some motor power to the process it's pretty easy. The box on the right was fired yesterday. A box of new brass started today, with a few minutes work.

 

[Dogtown]

You guys motivated me to try something besides pulled M33 Ball. Kind of surprising that it has that cavity in the base.

 

[biffj]

A few reasons for the cavity, first it moves the CG of the bullet forward which can help stability. It also can help the bullet expand into the rifling. I've heard some other reasons but many seem odd. My guess is you won't get any better engagement if you're loading for subsonics. Not enough pressure....
I found the turned solids worked much better in my 33XC. Accuracy was more consistent and I wasn't spinning the jackets off them.

Frank