Trail Boss cast Bullet Load in .308 Win?

[Sistema1927]

I have loaded Trail Boss in .30-30, creating a nice "plinking" load using a 165 gr hard cast FP over 6.9 grains. Probably around 1000-1100 fps, and very accurate.

I have been thinking (always dangerous, I know), that a similar load in .308 Win cases might allow me to get more utility out of my Ishapore Enfield in 7.62x51.

Has anyone tried this? I don't want to experience detonation by loading too light, and IMR says that they haven't done any work with this powder in any bottle neck rifle cases other than .30-30. I am thinking (there I go again), that since the .30-30 and .308 differ about 20% in case volume, that a starting load for the .308 should be ~7.8, which is 120% of the .30-30 starting load of 6.5. This is still well under the .30-30 max of 9.0.

I am open to any suggestions or comments, and don't anticipate starting this little project prior to doing a bunch more research.

 

[griz]

Your reasoning seems sound to me, and the bolt action should be stronger anyway giving some more safety margin. Maybe look at the data for the 45-70, not for a load but to see how it behaves in an even larger rifle case. Of course I have done even less research than you or IMR, but I think I would try it.

 

[Sistema1927]

I thought about that. They prescribe a starting load for .45-70 of 14.0 (max of 16.5) for a 300 grain cast bullet. That is almost twice the weight that I want to use, in a significantly larger bore, with a straight case. Kind of hard to interpolate there, but my load is approx. 1/2 for a bullet approx. 1/2.

(Of course, they recommend 12 to 13 for a 405 cast bullet in the same caliber. So much for a straight interpolation!)

I am sure that in a couple of years plenty of folks will have figured out what works, but I don't know if I want to be one of the first.

 

[Vern Humphrey]

Ed Harris' "The Load" for .30 caliber rifles with cases .308 size and larger is 13 grains of Red Dot with any reasonable bullet weight. Red Dot fills the case about halfway full or more, and obviates the need for fillers or "positioning the powder" before firing. For .30-30, you should cut that in half.

If Trail Boss is what you're committed to, compare volumes of the .30-30 case and the .308 case, and scale up the load accordingly. I would set the max charge at 1.5 times what you're using in .30-30 (or around 10 grains), and work up slowly.

 

[444]

People are playing around with Trail Boss in bottleneck rifle cases (jacketed bullets) on www.silencertests.com including .308. Look under the ammo section/General Ammo of that board (you will need to register).
The goal is to work up a good subsonic load for use with a suppressor while still achieving a decent volume of powder in the case.
I posted my results of working up a load for the .223 Remington cartridge and the 77 grain Sierra Matchking bullet. I came up with a load that was subsonic and very accurate out to about 75 yards. The report (with a suppressor) is truely Hollywood quiet.

 

[Sistema1927]

Thankls for the responses. Based on the info from the silencers site, it looks like 10 grains is a better starting point, and then slowly work up from there.