338 Federal Subsonic loads

[Aussie26]

I would like to make some subsonic loads for my Federal 338. I've been reading some of the info on here for 308 subsonic loads which I think should get me in the ball park. So far I'm thinking of using RN 250gr with Trailboss powder starting at about 12gr.

Has any one here played with 338 Federal Subsonics? What are your thoughts on my starting load above?

Any info much apreciated

[LouBoyd]

Aussie26, you didn't mention the length and twist of your barrel or the type of action. Without that its just guessing. It would also be good to know what sort of performanc you want to give an idea if it's practical at all.

I've run computer simulations (Quickload) to see what might work for my DPMS LR-338L. It has an 18" x 9" twist barrel. I didn't come up with anything which I think would come close to cycling the action without extensive modification of the the gas system including moving the location of the gas port. Like the 308, there's just way to much chamber volume to be a good subsonic round. If that barrel were on a bolt action there would be better choices.

If you just want subsoinic reduced loads for just about any bolt action cartrige there are two methods to explore. One is shooting lubricated cast lead bullets. They usually have decent accuracy to a couple of hundred yards. Without knowing a specific barrel length and bullet I can't suggest a load.

Another way is to make reduced volume cases by "filling and drilling" the case with solder or epoxy reduce the chamber volume to something reasonable. The Federal 338 had 57.5 grains case capacity. The 338 Specter, a cartridge known to perform well subsonic with 250 grain jacketed bullets has 28.8.

[HUNTER2]

FYI...Just got an e-mail from Dave at Lehigh Bullets. Testing is complete on .338 and 458 subsonic bullets. Will be on website as soon as quantity is in stock....375 is still in testing phase......I should have noted before - They are hunting bullets that will open up at subsonic velocities!!!!

[Aussie26]

Thanks for the help guys.
The rifle I'll be using this load in is a bolt action with a 20 inch Maddco barrel with a 1 in 10 twist. I'm hoping to be able to hunt pigs with this round. I'm thinking about starting with a RN 250gr Hornady projectile.

[Aussie26]

Does anyone else have any handy advise for the above???

[Tiffy]

Here is an add for one I have just sold, 1:10 is marginal for 250gners, fine for RN though, have a look, may be of interest.
Cheers
www.gunworks.co.nz


Rifle is set up for suppressed use, to launch a heavy bullet below the speed of sound for quiet operation, here are some examples of loads.
250gn bullet with 11gns trailboss powder 900fps
250gn bullet with 16gns trail boss powder
1050fps

Comes with rings but NO SCOPE.


Barrel twist is 1:10, stabilises 250gn Sierra gameking, shoots under 1", wouldn't shoot 250gn Hornady BTHP as they were a bit longer. Ideal bullet would be the 250gn round nose. Won't stabilse 300gn SMK, which at the current price is probably not a bad thing!

http://www.trademe.co.nz/Browse/Listing.aspx?id=222960175


http://images.trademe.co.nz/photoserver/tq/34/95707834.jpg

[Tiffy]

I posted a bit of info on this calibre/ suppressor etc yesterday but it never showed up, so I'm seeing if this post sticks before I bother typing again.
Cheers

http://images.trademe.co.nz/photoserver/tq/55/95707855.jpg

[Aussie26]

My first test of sub loads for my .338 Federal have been very succesful.

12gr of trail boss will 250gr woodleigh projectiles gives me an average of about 1030fps. After about 30 shots the slowest was 1001fps and the fastest was 1080fps. After I have let the barrel cool my first shot was always around 1010 to 1020fps. Will the 3rd and 4th shot starting to get a little quick at mostly around 1040 to 1060fps. Never fired more than 4 shots in a row.
Groups have been around 1 inch at 50 meters. 2 1/2 at 100 meters.

Overall I was pretty happy with the resuts. And havnt felt a great deal of need to try and improve on it.

Cheers