308 subsonic loads - no trailboss no n32c

[CiPo]

Hi.

I'm looking for powder recommendation for subsonic loads.
My current recipe is:

Reduced capacity 308 brass
5gr vitavhuori n330
168gr smk
Cci BR
Coal 71mm

I want to use lapua brass in the future but I cant purchase trailboss or n32c. Do simeone have data for powders like vithavuori n320 and lapua 220gr subsonic bullets?

Thanks!

 

[Dogtown]

I used the classic 10.5gr of Trailboss with the Lapua 200gr Subsonic for years - good combo. But given your situation, let me run some numbers for you...

So here I set the parameters for >70% case fill with a targeted velocity of 1050fps. It looks like the slow magnum powders are your Huckleberry

 

[CiPo]

I used the classic 10.5gr of Trailboss with the Lapua 200gr Subsonic for years - good combo. But given your situation, let me run some numbers for you...

View attachment 7618833

So here I set the parameters for >70% case fill with a targeted velocity of 1050fps. It looks like the slow magnum powders are your Huckleberry

Maybe % of burnt podwer are a little on the low end.
Some of my friends are using n320 but with case filler that i want to avoid.

 

[Dogtown]

Ah good point - didn't think of that.

 

[MarshallDodge]

Just an FYI, I tried some N32C in 223 and 30-30 and it didn't work that great.

Do you have access to Unique?

 

[CiPo]

Unique is not available in Italy due to pollution restrictions. Same as trailboss and n32c.

Maybe i'll have some luck with 12 gauge powders. I have to find a density chart, they all are about the same in terms of burn rate.

 

[stefan73]

I figure you should be able to get your hands on Vhit. Might be a good way to go with that 20n29.

 

[Dogtown]

This is the best I can see with N320. The main problem is the Fill % is 30, which is a really bad idea. You'd need some kind of filler to make that work and that can often be problematic. Time to switch to .300BLK

 

[CiPo]

300 blk is on the list.
Wich type of filler do you raccomend?
No need to be suppressor-proff since in italy are not allowed and military restricted items.

 

[Dogtown]

I've never used any type of filler in a load (even when fireforming wildcat cartridges), but there's probably someone here who has and can offer suggestions.

 

[redbullitt]

I saw in the op you mention reduced capacity brass. That sure does make loading 308 subs a bit more interesting.

Do you plan to keep using those cases or move to full capacity 308 lapua cases?

Details on the brass, capacity etc would be helpful if possible if you plan to find more data on the reduced cases.

Otherwise, filler for the full capacity cases... people use things like cornmeal and dacron pillow stuffing. Not liked fillers much myself though as the can mess with the chamber supposedly sometimes I've heard.

 

[CiPo]

I use reduced capacity brass with some success but I want to move to lapua full capacity since i use them for every load.

 

[redbullitt]

Gotchya, makes sense to me if you can find a workable load that does what you need.

Honestly you might just be ahead using those reduced cases, provided you have enough or a reliable source for them... 308 subsonic loading is a persnickety beast to get reliable and consistent results with at distance even with trailboss and similar powders.

Most 308 subs I've messed with using less than ideal powders never have the velocity spread I'd like... reduced cases tend to fix that and open up powder options enough to get good results at 150 yards and beyond... it might be best to save the lapua brass for full power loadings. I know that's not what you want to do really, but if you are going for subsonic and consistent with less than ideal powder availability, I think it needs to be said.

 

[jambau]

Has anybody tried Unique? I have a full container that's been sitting on the shelf for years.

 

[ward1102]

I used the classic 10.5gr of Trailboss with the Lapua 200gr Subsonic for years - good combo. But given your situation, let me run some numbers for you...

View attachment 7618833

So here I set the parameters for >70% case fill with a targeted velocity of 1050fps. It looks like the slow magnum powders are your Huckleberry

How did you get this information? This is amazing

 

[Dogtown]

QuickLoad Ballistic Prediction Software – Neconos.com

www.neconos.com

One of the best investments I've ever made in reloading....

 

[ward1102]

How did you get this information? This is amazing

Do you have time to run another?
308
18” 1 in 10”
Using Hornady 175 gr subx or 190gr subx?
I don’t have the 170$ to buy the product at the moment.
Thanks

 

[Dogtown]

No 175 SubX in the library, so here's what it says for 190s

Not good data, I think...

The problem in general with this kind of stuff is that you can get into a danger zone with Filling/Loading Ratio below 70% very quickly. Trailboss is popular because it fills cases quickly without generating that much power. A good rule of thumb with developing subsonic loads is to start with a safe supersonic charge weight and then work backwards until you're subsonic, but you have to be careful with low fill % otherwise you may get a detonation.

Hodgdon suggests 2.69" COAL with 190 SubX and 10.5gr of Trailboss, so maybe start there....

 

[ward1102]

QuickLoad Ballistic Prediction Software – Neconos.com

www.neconos.com

One of the best investments I've ever made in reloading....

Thanks

 

[BigSkyRF]

Has anyone tried a flake shotgun powder like Universal? I'm looking at a 175 subX in a 18" 10T