We have a question for the community. Hodgdon has recently published subsonic load data: https://hodgdonpowderco.com/wp-content/uploads/2023/04/subsonic-data-final-1.pdf
The list contains the following load data: .308 Win, 190 GR Hornady Sub-X, 2.69 C.O.L.: 2.690'' - 13 GR H322 Hodgdon
The bullet is 1.3'' long. Seated depth is then 0.63''. The empty case capacity is 56 GoW, the powder bulk density is 55.8 lbs/ft3.
So the fill rate (volume taken by powder in the cartridge) for this suggested load is around 33%. Only one third of the available cartridge is taken by the powder.
HOW CAN SUCH A LOAD ENSURE CONSISTENT IGNITION BY THE PRIMER? Has someone tested this load? Any feedback in general at what minimum fill rates you start to get problems /nervous?
Hi - we got some direct feedback by mail, thanks for that. The current punchline is that people would accept fill rates of only 50% when a filler is used. We have updated our subsonic load data accordingly and accept fill rates with a minimum of 40% and flagg these loads that a filler is recommended. We leave this post open in case there is more feedback.
I used this load data this weekend out of a ruger bolt gun only made up 10 rds for trial and didn’t use any filler and all 10 fired and velocities were around 1050fps out of a 20 in barrel
Bonsoir, j'habite en France donc pas accès a vos poudre Hogdon, Imr, Accurate etc etc ... En rechargement subsonique qui fonctionne à merveilles pour moi, dans une Bergara au twist de 1/10 est la 190 gns Sub-X de chez Hornady et 9 grains de BA9. Je sort à 289 m/s Trou d'évent de la douille uniformisé pas de kapok ni du dacron, de toute façon avec ou sans cela ne sert absolument a rien. A 100 m 5 cartouches tiennent dans un diam de 2 cm et traverse un poteau en bois de 120 mm X 120 mm sans aucun problème.☺️
Happy New Year!!! Not sure where we are on the Sub Sonic application scene? When working with these very low velocities always document all your variables that may change or affect the set (goal) velocity. Rifle/Barrel/Length/Twist/Grooves/Powder/Fill/No Fill/Bore Clean after each use/Reliable Powder Scale/DO NOT USE COTTON/same chronograph for each test/barrel cool/not cool/ Once you have established 'your' set of preferences you can begin. Choice of primers: AR Type Small: Rem7½, SRMag, CCIBR4, SPMag, AR Type Large: Fed215M, CCI#250, Fed210M, CCIBR-2. Use an adjustable gas block. Attached is my comprehensive list of Sub Sonic Cartridges. Enjoy. Have a Great NEW 2025.
I'll be testing the 190gr Sub-X in 308-Win in the near future. Currently, I'm using a 208gr Hornady A-Max with IMR-4895 with no filler. So far, with no ignition issues.
Minimum fill would be anything that will cycle the round without adjusting your gas block on a semiautomatic (AR type) rifle. Using powder like Trail Boss will nearly fill the case without using filler.
I would recommend using IMR/Hodgdon data from:
https://hodgdonreloading.com/rldc/
Less confusing and reliable. The best powder is Trail Boss
I've used grits or cotton before as a filler, but there maybe something out there that is better ?
Hi - just checking if anyone has a view? What is the minimum fill rate you are accepting for normal and for subsonic loads?!