.300 Whisper to .300 Blackout?

[tobnpr]

Customer I'm doing some other work for wants to send me a .300 Whisper barrel to be rechambered to AAC .300 Blackout.
I know these two are damn close in dimensions but I've never worked with either yet. Since the Whisper is CIP all the dimensions are metric so it's a pain to try to convert and check the critical ones.

Anyone know if the Blackout reamer will clean up the Whisper chamber without a setback?

 

[Bill K]

Why not ask the maker of the reamer, you have or are getting ? They should be able to advise you on that issue.

 

[rockrat]

I think the neck is a bit bigger in diameter on the Blackout, but as said, ask the reamer mfg

 

[dhagerty40]

I cannot help with reamers specs on either but here are the cartridge specs for each. the drawings are in both metric and standard measurements.

 

[Old Navy]

I guess the only reason we have a Blackout is because someone liked the name better.

 

[dhagerty40]

I guess the only reason we have a Blackout is because someone liked the name better.

actually no. The name and cartridge were patented by the originator for the 300 Whisper. To get around the Patent, the 300 AAC blackout was formed.

 

[Old Navy]

actually no. The name and cartridge were patented by the originator for the 300 Whisper. To get around the Patent, the 300 AAC blackout was formed.

I thought maybe something like that. I remember reading the first test of the new cartridge. The gun was suppressed and the ammo was sub-sonic. They said all you could hear was the action cycling.

 

[tobnpr]

Update and question...
Cust. finally got around to sending the barrel in, it's a Savage nutted barrel- 12" shorty.

Obviously can't set it up through the spindle.
The muzzle end is already threaded for a can, not much to grip there but I'll put in the Buck 6-jaw set tru.
Dead center in the chamber to line it up and run the breech threads in the steady.

I think I only need .040 or .050 with the Blackout reamer to clean up the Whisper chamber.
Set up the reamer with a micrometer stop in the floating holder and run it home. With the floating holder it should follow the existing chamber.

Don't have a receiver fixture like Pastor's to set up and indicate, but I don't think there's a need to anyway for the little bit that needs to be done. Would anyone here take a different tack, and if so- why?

 

[Dusty Stevens]

Update and question...
Cust. finally got around to sending the barrel in, it's a Savage nutted barrel- 12" shorty.

Obviously can't set it up through the spindle.
The muzzle end is already threaded for a can, not much to grip there but I'll put in the Buck 6-jaw set tru.
Dead center in the chamber to line it up and run the breech threads in the steady.

I think I only need .040 or .050 with the Blackout reamer to clean up the Whisper chamber.
Set up the reamer with a micrometer stop in the floating holder and run it home. With the floating holder it should follow the existing chamber.

Don't have a receiver fixture like Pastor's to set up and indicate, but I don't think there's a need to anyway for the little bit that needs to be done. Would anyone here take a different tack, and if so- why?

Man you ought to work toward getting that viper fixture just for times like this. Havent used mine in a long time but those AR pistol barrels get in there when i need. What youre wanting to do is perfectly acceptable though. Chuck up the barrel as close to the steady as you can

 

[AccelR8]

If it were me, I'd take a look in the throat with my mighty Teslong and make sure it looked pretty much even all around. I've seen some crooked, with free bore on one side and lands all the way to the neck on the opposite side.

If it looked okay so far, me, I'd simply put the muzzle threads in a collet. I would assume the threads are concentric to the muzzle, more so than the barrel OD. Or in your case I'd stick a pin of about 5/8” in the Buck Chuck first and check to be sure it was zeroed. In other words I wouldn't put an indicator on the barrel OD and move the chuck.

Center in the tail stock and then steady on the tenon threads. I'd probably run a test indicator in the chamber neck throat to make sure nothing too wild is going on. Then use a fully floating reamer holder, I have a Bald Eagle.

But I'm a machinist, not a gunsmith so...

 

[tobnpr]

What's wrong with this picture , WTF....

 

[dhagerty40]

What's wrong with this picture , WTF....

just a minor screwup

 

[Dusty Stevens]

Looks like a machinist with no gunsmith experience chambered it. Most times the hammer stamps tell the tale

 

[tobnpr]

Waiting on a reply from the cust, I'm assuming he has no clue.
Best as I could measure, that's about .075+ deep. If there was typical .125 protrusion beyond the breech that's about .200 of unsupported .223 case. I'm surprised nothing separated on him.

I needed to clean up the BO chamber anyway, now I'll need to go a bit deeper after facing that away.

 

[AccelR8]

I bet it was done with countersink!

 

[tobnpr]

Most times the hammer stamps tell the tale

Ya think?

Even when I used to use hammer stamps, I at least used a shop-made jig to keep everything nice and purty.

 

[Dusty Stevens]

Ya think?

Even when I used to use hammer stamps, I at least used a shop-made jig to keep everything nice and purty.

Hey those guys are from arkansas