Lapua Brass, 139 Scenar, and 4831 SC in 260 Remington

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DMT

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I am loading Lapua brass, with 4831 SC with 139 Scenar. At 44.3 grains when seating the bullet, there was a bit of crunching of the load, whereas at 44 grains it didn't seem like much. Each load is individual weighed, and once the brass is filled, it is tapped and held on a vibrating motor to try to settle the grains in a bit more compact. From my Nosler reload info, it quotes a load as high as 46 grains, which is almost a full case. LOA is 2.75 and that is about 0.028" off the lands, so can only come out a bit more.
Any suggestions on getting it to settle more? I could try a long drop tube, but feel with the tapping and vibration, I am getting the powder in the brass as compact as possible.
Let me know your thoughts.
 
The problem you have is the bullet, Scenar is long & pointed (VLD), seating this to COL of 2.75 means you'r seating the bullet deep. You can seat out a bit more reduce the .028 to .015, if that will fit your mag. To settle the powder try tapping the brass base (gently) on the bench as you fill it.
Enjoy
 
I load .260 Rem as well, and I am surprised by your numbers. It sounds like your chamber may be smaller than spec. The "textbook" OAL for .260 Rem is 2.800", but based on what you have said, that is significantly longer than what your rifle's chamber is. If you loaded to 2.800", you likely would not be compressing your powder. I use 139gr Scenars as well, and load to an OAL of 2.800 and in my rifle, I have the room to load even slightly (a few thou) longer if I need to.

Are you able to chamber and fire factory ammunition?

Another option would be to try another powder that does not require as much powder per round. I am using IMR 4064, and my load is roughly 36-37 grains. That gives me lots of room to seat the bullet.
 
I agree with Hoag, that seems like a lot of powder. In my 6.5x47L with the same 139 scenar's, which has a very similar case I think, I'm using 38ish grains of varget. You might need to try a different powder.
 
If you like that bullet and powder, you should consider lengthening your throat so that you can seat it to 2.800" or near your magazine capacity if greater.

The slight "crunch" you heard is kernels being forced against each other, but I wouldn't be surprised if after tapping the round a few times that you can shake it and hear slight powder movement. The act of seating was more a forced rearrangement in a confined space than the crushing of powder. Remove a bullet and examine the powder and you'll see.

I have used compressed loads of H4831SC many times (as recently as last week in an 8X57) as do many others. If you want to start a fight here within five posts, start a thread on compressed loads.....
 
My .260 load is 47gr H-4831 in a R-P case with cci 200s for a hair over 2800. You didn't say what your velocity is but if it's around 2800 and your load shoots good then don't worry about it. If the crunching doesn't make you warm and fuzzy try another powder or switch cases to one that is thinner than the Lapua. I've got brass that have been shot 7 times with this load in my rifle.
 
According to the Nosler reloading data for a 140 grain bullet, his load of 44.3gr of 4831SC is (theoretically) just about perfect.

My concern wasn't with the compressed load. I was concerned because to me, it sounds as though he can't chamber a round with an OAL of 2.800 without being significantly into the lands. I'm no expert, but this sounds to me as though the rifle's chamber may be too short to fit a full sized round. That was why I asked if he was able to chamber a factory round.
 
I use N160 in my 260rem, takes up a bit less case capacity and gives a bit more speed too grain for grain.
2.75 seems pretty deep for being that close to the lands. What's the spec on that chamber/reamer that was used?
 
I have a load for my 260, (can't remember the specs without looking it up) using H1000 and 139gr Scenars. I know the lapua case is filled to the top, literally, to the top. I seat the bullet in. Lots of crunching. Load shoots amazing.
I wouldn't worry about it too much as long as you have no pressure signs
2.900" is what most of my 260 loads are finished at, that's the max my Sako Magazine will hold
 
I load for the 260 rem , Lapua cases 120gr GMX or 125 Partitions. I also use 4831sc the cases are full to the top with my particular load. but well within book specs. I've never had a problem. I just shoot em, no pressure signs ect with it.
 
Don't worry about compressing the powder, it does not affect the load at all. I have used loads so heavily compressed that I had to crimp the bullet in the cannelure to keep it from oozing out.........this was one of the most accurate loads I ever put together and had the lowest ES of any load tried in that 340. The only powders I have found that do NOT like heavy compression are the slow Reliant powders, from RL 17 and slower. They do very odd things when heavily compressed and almost always lose velocity as compression goes up. I strive for compressed loads in almost all the calibers I load for, with some exceptions. But in my turnbolt hunting rifles it most definitely is the norm.
 
In Nosler , there is no load using Varget and 140 grain projectiles. How about in any of the other sources?
thanks for all the useful information.
 
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