Lucky1,
Id always been of the understanding that a slower twist was used in the 300 Whisper back when JD Jones created it so that at subsonic speeds those long heavy bullets would tumble on impact and create larger and more reliable wound channels. Gotta remember, that cartridge was designed to run subsonic in the AR platform for law enforcement doing no knock entries and the like and they were unhappy with 9mm bullet performance in those days. (Yeah, im older than dirt.
Time passes and Advanced Armament Corporation is charged with a quite similar task and in my eyes basically recreated the Whisper, giving it a longer bullet seat in the chamber and having SAMMI bless it.
Summer of '25 I bought a 300 Blackout barrel from Midway for my Encore. What arrives is an SSK Industries barrrl marked 300 Whisper. I didnt put a lot of thought into until now. I asked chatgpt to find info on the twist for that barrel and what it could find about what JD may have said about it
Well, I was hoping I wouldnt have to run a tight patch in mine to find out, but I do. Yet Chat came up with an interesting article where JD says he experimented with 1:6, 1:7, 1:8 and settled on 1:8 as the best compromise for subsonic accuracy. Said nothing about on target performance. The semi solid kind amyway.
Ive not shot that barrel in a while but have got cases loaded up im shooting over the weekend. In memory from last year I was getting good results out of Lee's 312185, Lyman 311299 and the RCBS 150 CM
Will be shooting Lyman 311299 this weekend ill share what happens and ill push a patch through my barrel and tell ya its twist.
As a side note, I got this this barrel because my AR will not shoot cast worth a hoot. Jacketed it shoots like a house afire so I feed it what it likes.
