question re a 300 blk or whisper

Hi guys,
Im running a suppressed .308 that is extremely, extremely quiet, it’s an old omark thats bore was not up to standard for target shooting so I made it into a project rifle, I run a rather large suppressor on the old girl.

I have loads that are based on 220gr out to 240gr (when I can borrow that mold) from lead cast projectiles I make and size to suit barrel, roughly .310 out to .311. I I run it around 16.6 or normally 18BHN in hardness.

Ive also projectiles that have a HP that is brutal, but yet untested, their length is no way near as long as the ones mentioned above

The reason I prefacing my question is that I am considering a 300wisper or Blackout as a project and i have the ability to make very good loads using lead projectiles that i cast myself. I dont just make a heap and shoot em, if they are not up to a high standard when i cast them, they go back into the pot! Its good therapy :D

I am curious if anyone is running such a rig, and if they don’t mind sharing some info on usable case capacity, what is the OAL of the round, Barrel lenghts and rate of twist, as I want to work out what molds that I have that may well work in this project!

Also do you run lead (gas checked) through your M4/AR

Lead in a AR is always a funny topic
Heaps of opinions and story's of bad stuff, but no real info ever provided in evidence to confirm it
Anyway, around 10gr of 05 or 07 Is where you will be with a 220 or 240 in a whisper/blackout so case capacity is spot on

Thanks Spanners,

ive had a heap of conflicting info on Lead in Gas Guns, however one particular clever bugger ran it some time in his with no issue,( i think to be fair his was a mini14 )

the only trick that i have found is to really clean the barrel and remove copper as lead doesnt seem to shoot well from a barrel with a lot of copper in the barrel, otherwise ive really not done a lot to do with semi auto's, except my M305.

The projectile that i intend to use (oneday!) measures 1.254 in lenght with a gas check, that is the 240gr

the powder choices you recommend are 2207 and 2205?

Cheers

Hogdon 110 9.8 grns 240 grn matchking,19.2 grns 125grn BT.I have not had anything to do with cast bullets

Twist will be the only issue with a really heavy pill
H110, w296, 05, 07, and a few others around that speed will work.
I'd have to check my data for what I'm loading for subs. 07? Supers 296
I think shoot a couple of jacketed supers after a session of lead subs and no issues will come about with has system

Thanks, by really heavy pills over what grain ?????

The change in accuracy ive noticed has been with bolt rifles, so again this will be a learning curve. i am going to size some 223 projectiles (cast) and run them for a while and see what effect it has on the rifle, just curious!

For subs i was looking at say 2400 or TB Red dot??

Now silly question time, how well does the 300 or whisper cycle on subs?

300 Whisper suppressed subsonic - YouTube

Quote:

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Originally Posted by Tertle

Now silly question time, how well does the 300 or whisper cycle on subs?

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Here's mine. 300 BLK but i had to do some work to get it cycling. Took all the internal weights out of the carbine buffer in the end, and drilled my gas port out a bit. It's carbine length gas, so with a sub-sonic load, there's not a lot of pressure at the port.