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Subsonic 308 without trail boss

In my 45/70 subsonic loads I use Unique with toilet paper wadding. The paper tends to be a bit singed around the edges. For hunting loads when there is a high fire danger I am using model rocket parachute wadding. It is a biodegradable paper treated with fire suppressing chemical.
I don’t want to be known as the guy who started a fire that burned down a Texas town.

 
Check out the Hodgdon Reloading site. I'm seeing more data on subsonic loads with alternative (non Trailboss) powder for a bunch of chambers.
 
I just learned there is a new Hornady subsonic bullet line called Sub X. The Hodgdon site shows data with Benchmark - 175 Sub X/12.8 benchmark/1066 fps.

What is different about the sub x bullets? Has anyone tried benchmark with regular 168s?
 
I finally fired some loads. The Hodgdon site shows 8.0 grains of Titegroup with a 168, so I tried 7.5 grains with a 150 Hornady fmj at 50 yards. I used lake city '18 brass weight sorted and neck turned and remington 9-1/2M primers. Five rounds into one hole success! It was just too fast with 7.5 grains - average was 1188 with a high of 1227, a low of 1164, with es of 63 and sd of 19.8.

Hodgdon also shows loads with benchmark, but only with the new Hornady Sub X bullets. Well I tried it anyway with 168 ELDM's, same brass and primers, and it was a disaster. I started with 15.0 grains. The first shot went 1245, then each following shot dropped about 100fps sequentially to a low of 690. I could see the bullets as they walked down the target! Average was 852, es 555, sd 188. The brass came out more sooty with each shot, so all I can figure is the pressure was too low to fully seal the brass and the barrel carboned up. I bronze-brushed the barrel and tried a couple more with 14.0 gr benchmark. They were also super slow, so I stopped.

Titegroup worked great except for the es and sd. I can hardly wait to try it with 168's out to 100y. TG is a compact powder, so I wonder if something more bulky like red dot might light off better. But I'm also wondering about CFE Pistol. It's slower than tg or red dot, more in the power pistol range, so maybe I can run a few more grains to add bulk.
 

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Titegroup will work OK but is more prone to positional burn rate changes.

Try a fluffy, bulky, FAST powder and report back... Trying to increase charge weight by using a slower powder will just make for a dirty, inconsistent load.
 
I finally fired some loads. The Hodgdon site shows 8.0 grains of Titegroup with a 168, so I tried 7.5 grains with a 150 Hornady fmj at 50 yards. I used lake city '18 brass weight sorted and neck turned and remington 9-1/2M primers. Five rounds into one hole success! It was just too fast with 7.5 grains - average was 1188 with a high of 1227, a low of 1164, with es of 63 and sd of 19.8.

Hodgdon also shows loads with benchmark, but only with the new Hornady Sub X bullets. Well I tried it anyway with 168 ELDM's, same brass and primers, and it was a disaster. I started with 15.0 grains. The first shot went 1245, then each following shot dropped about 100fps sequentially to a low of 690. I could see the bullets as they walked down the target! Average was 852, es 555, sd 188. The brass came out more sooty with each shot, so all I can figure is the pressure was too low to fully seal the brass and the barrel carboned up. I bronze-brushed the barrel and tried a couple more with 14.0 gr benchmark. They were also super slow, so I stopped.

Titegroup worked great except for the es and sd. I can hardly wait to try it with 168's out to 100y. TG is a compact powder, so I wonder if something more bulky like red dot might light off better. But I'm also wondering about CFE Pistol. It's slower than tg or red dot, more in the power pistol range, so maybe I can run a few more grains to add bulk.
Well thanks for trying it out and saving me the hassle. I use Benchmark in my .308 for 165/168 grain bullets already at 41 grains, and had hoped for an easy subsonic fix.
 
Today I shot 168 ELDM's with 8.0 grains of titegroup and 8.0 of Red Dot. The titegroup was still too fast - 5 round averages of 1160 and 1177. The red dot was perfect, 1067 and 1070. Here are the red dot targets at 100 yards. Better than some groups I get with normal loads! Had good and bad spread and sd numbers with both TG and RD. There was one extra fast round in the second target that blew the group and the es number. The target is wrinkly from it starting to rain this morning, which also prevented me from shooting at 50 yards. I think cloverleafs at 50 will be routine with red dot.
 

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Today I shot 168 ELDM's with 8.0 grains of titegroup and 8.0 of Red Dot. The titegroup was still too fast - 5 round averages of 1160 and 1177. The red dot was perfect, 1067 and 1070. Here are the red dot targets at 100 yards. Better than some groups I get with normal loads! Had good and bad spread and sd numbers with both TG and RD. There was one extra fast round in the second target that blew the group and the es number. The target is wrinkly from it starting to rain this morning, which also prevented me from shooting at 50 yards. I think cloverleafs at 50 will be routine with red dot.
I'd be happy with either group, shooting subsonic. I think the ES/SD numbers probably mean little when dealing with small charges in a relatively large case.
Scott
 
 
Just discovered this thread.... I have a 1/10 twist 308, Lapua Palma SR brass, and Hornady 190gr Sub-X bullets. Trail Boss is unobtainium and I am looking for alternative powders. Hodgdon's load data shows 13.3gr H4895. I have a bunch of 8208XBR which is very close in terms of burn rate. Has anyone tried any 8208XBR loads?
 
Just discovered this thread.... I have a 1/10 twist 308, Lapua Palma SR brass, and Hornady 190gr Sub-X bullets. Trail Boss is unobtainium and I am looking for alternative powders. Hodgdon's load data shows 13.3gr H4895. I have a bunch of 8208XBR which is very close in terms of burn rate. Has anyone tried any 8208XBR loads?
Hodgdon will warn you not to substitute any other powders for the H4895 reduced load data. This is because of the dangers of powder detonation, as well as inconsistent ignition.

My recommendation is to try a pistol or shotgun powder such as Clays, Titegroup, or Red Dot. I find that they burn a little cleaner than powder typically used for rifle.
 
Hodgdon will warn you not to substitute any other powders for the H4895 reduced load data. This is because of the dangers of powder detonation, as well as inconsistent ignition.

My recommendation is to try a pistol or shotgun powder such as Clays, Titegroup, or Red Dot. I find that they burn a little cleaner than powder typically used for rifle.
THanks for the advice. Where is this warning? I don't see it in their subsonic load data PDF. I just finished loading up 20 rounds with 13gr 8208XBR to an OAL of 2.690. Let's see how this goes.....
 
THanks for the advice. Where is this warning? I don't see it in their subsonic load data PDF. I just finished loading up 20 rounds with 13gr 8208XBR to an OAL of 2.690. Let's see how this goes.....
Just because the burn rates are similar on a chart, doesn’t mean the two powders react the same. Flashover/detonation is a serious and dangerous event. I would not fire those rounds without further investigation.
 
FWIW - I reached out to Hodgdon. Their response:

"Thank you for contacting us. There are only certain powders that will work for these reduced loads with these lower case fill percentages. We thoroughly test each load and powder for case position sensitivity when developing these loads. Only powders listed would be appropriate."
 
Ok but 60% of a full charge of h4895 will not be subsonic. I haven't been to the range in 6 months due to multiple pretty lame reasons, but next time I shoot subsonic it will be with red dot. Also H4895 is pretty much unobtainable too. I heard it's no longer being imported. Would imr 4895 work?
 
One bullet which was exceptional for me in 308 was the hornady 170 gr FBFP used for lever action in 30-30.
i was loading it with a fast shotgun powder and a light crimp on the crimping groove. I was getting between 1/2moa to 3/4 moa at 100m with it.
Crimping and switching to magnum primers and readjusting the load can sometimes be very beneficial.
 

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