Sub or transonic loads for 308

bpost

My buddy is looking for a cast bullet load that is transonic for his suppressed bolt action toy (308 Win. 173 grain Lyman bullet). Lyman lists loads at about 1250 FPS. Does anyone have a load slower. I have not gone below starting loads.

charliemeyer007

Use the Unique load. You can slow it down until the bullet barely makes it out the barrel. I had a 8mm Mauser load that I couldn't hear the difference but the dogs a couple hundred yards away would bark with .1 more grains of unique.

Ray B

The lowest loading I see for the #311291 w/GC for the 308 Win in the Lyman manual is 8.0 grs of 700X for 1209 fps & 23,400 CUP. However, using data for the 300 Sav, 7.5 gr Red Dot gets 1185 fps @ 24,000 CUP. There is data using faster powders where the velocities get down to about 900 fps, but I'd have to search for the book.

bpost

quote:Originally posted by Ray B
The lowest loading I see for the #311291 w/GC for the 308 Win in the Lyman manual is 8.0 grs of 700X for 1209 fps & 23,400 CUP. However, using data for the 300 Sav, 7.5 gr Red Dot gets 1185 fps @ 24,000 CUP. There is data using faster powders where the velocities get down to about 900 fps, but I'd have to search for the book.

I should have said I am using the Lyman 311041 mold.

lostriver1

hi, use unique just load it down to the speed you want. I used it for fire lapping. there you want as slow as you can get it to go out the bore. did a 308 but didnt right the load down.

charliemeyer007

I would think about 8.5 grains of Unique and work up until you hear the crack.

Ray B

A bullet maker friend of mine had a rule of thumb regarding minimum loads. He took the case capacity and divided by ten; eg 270 Win cap = 60 grs, /10 = 6. this amount was what he would load using Bullseye. I used this load in a 270 and 130 grain cast bullets. I chronographed the loads and avg 800 fps. I don't know what the equivalent weight bullet for a .308" bore would be.

Blacklion66

Trail Boss works pretty good

Okie743

Just a suggestion:
You might consider trying XMR5744 (check with accurate arms tech for suggestions)
I've referred to them when a reduced load was not listed for a caliber and they were not hesitant to make suggestions for their 5744 powder. (it's listed for some calibers for reduced loads and cast bullet loads. I started with cast bullet suggested loads but used jacketed bullets when testing for accuracy.

I quit using Unique because looks like burned dirt inside the barrel of a rifle when using reduced loads and also when using unique no consistent accuracy. When testing Unique the rifle would shoot to different point of impact if the barrel was pointed down vs pointed up before firing. (powder against the primer vs powder away from the primer. Look into the barrel after you fired a reduced load of Unique and sometimes you cannot see thru the bore.
For some calibers the powders were critical of type of primer used with reduced loads for consistent accuracy. I used pistol primers for some loads with good consistent accuracy results especially the 223 centerfire calibers reduced loads at 22 rim fire caliber velocities.

I never tried going sub sonic though.

RobOz

http://www.ramshot.com/faq/

Good info on loading down. ?21