Trail Boss In 338 Lapua Mag

[barnesuser28]

I am thinking about trying some trail boss in a 338 Lapua to test low end expansion with the 280 grain Barnes Lrx. Barnes says they will expand down to 1600 fps in water so i figure i will need about 1700 fps to get 1600 fps at 100 yards. Do you think i can get this velocity or even anything above 1600 fps with this powder in a 26 inch barrel? Has anyone tried trail boss in a 338 Lapua? Or will i be one of the first?

 

[Nimrodmar10]

You can probably get the velocity you want with Trail Boss but you won't be able to get it consistently. There is too much empty space left in the case after you find the correct ammount for the velocity. I use Trail Boss in my sub-sonic 308 rounds and it's very hard to get consistant 1050 fps due to the powder shifting to different positions inside the case. If I want any kind of accuracy at all, I have to load the round in the chamber, put the gun in a vertical position, bump the recoil pad twice on the shooting table, carefully lower the rifle to the shooting rest and fire it. I haven't tried using fillers in the case because I'm shooting it through a suppressor and don't want the inside coated with synthetic fiber or organic filler.

 

[barnesuser28]

What type of fillers could I use to increase the load density? I have heard about using them before but didn't know what materiall to use.

 

[Nimrodmar10]

I've heard of people using everything from cream-of-wheat to corn meal to polyester fiberfill to you name it. Some company used to make a fiber filler just for squib loads but it's been too long for me to remember the company or name. Try Google.

 

[barnesuser28]

Does using a filler affect pressures at all? Do you just pour your powder then add cornmeal until it is at where the base of the bullet would be when seated to the correct depth?

 

[barnesuser28]

well i picked up 2, 9oz jugs of trail boss yesterday. i am going to try it with the hornady 285 grain bthp bullets first just to get me close to the velocity that i want then i will switch to the Barnes to get my final powder charge. so do i need to put something like a piece of paper between the trail boss and the filler so they dont mix? or do i just pour the powder and put in the filler. (i am going to use cornmeal)

 

[Outlaw6.0]

Yes the filler will effect your pressure. The easiest way I can describe it is, the filler becomes a projectile as well (doesn't have anywhere to go except down the tube). You are adding to the mass of your bullet, by a LOT. I use the corn meal to fire form 6.5-06AI brass & it works really well, but this is done w/o a bullet.

Be extremely careful with this experiment, there is a gent here locally who decided to use corn meal to increase the consistency of his target rifle's full tilt loads. He now only has one eye & no thumb after his rifle grenaded on him.

Be very careful, I just can't advise doing that....

 

[barnesuser28]

I really dont want to use a filler unless absolutly necessary. But if i do end up having to use cornmeal i will be very careful.

 

[Nimrodmar10]

I don't reccomend using the corn meal either. Take a look at the thread below. It's one of the better series I've seen on using filler.

filler - Cast Boolits

 

[barnesuser28]

so you think i should use dacron as a filler?

 

[Kevin Thomas]

Actually, Cream of Wheat or Corn Meal both work great as a filler for fireforming cases, but that doesn't involve a bullet. I've used both extensively, and always with good results. The idea of using it between powder and bullet, however, seems like a phenomenally BAD idea. As has already been stated, anything that goes down the bore becomes part of the projectile weight (the "ejecta", to be more precise) and will most definately alter the load dynamics.

As for Dacron, Kapok or any other sort of filler, the NRA tech staff did some studies on this many years ago. They determined that it ocassionally caused ringing or bulging in chambers, as well as ocassional unexplained pressure spikes. It's your barrel, and has been mentioned, your eyes, face and fingers, but I'd steer very clear of this. Too many pitfalls, not enough benefit to justify the risks.

 

[barnesuser28]

Time to bring this thread back to life for some results!

I started with 27 grains which was the highest powder charge i had with me, and i decided to start with 27 because i didnt want to shoot the lowest powder charge i had with me (19 grains) and to shoot and have the bullet get stuck in the barrel.

27 grains gave me 1277 fps, 26 grains gave me 1357, and 25, grains gave me 1290 fps?!?!?!

I decided to save my bullets and not shoot anymore.

I am looking for 1450 fps, 1550 fps, and 1650 fps so i can test expansion of the Barnes 280 grain LRX at 1400, 1500, and 1600 fps in wet newspaper.

When i got home i pulled the remaining rounds and added powder to them and seated them closer to the lands to give me higher pressures and more velocity. I now have 28, 29, 30, 31, 32, and 33 grains loaded up to touch the lands. (the others were .100 off the lands)

 

[barnesuser28]

Another update.

These are touching the lands.

28 grains, 1374 fps
29 grains, 1404 fps
30 grains, 1465 fps (One of three goal velocities)
31 grains, 1446 fps
32 grains, 1511 fps
33 grains, 1552 fps (One of three goal velocities)

I loaded up three more rounds when i got home, at 35, 36, and 37 grains.

BTW: You can only fit 38 grains of Trail Boss in a 338 Lapua case until it flows over the case neck.

 

[Outlaw6.0]

What do you intend to use as a test media?