compressed load

[whiskey08]

got a couple of questions

when is a compressed load too compressed? Im loading 308 win, lapua brass and 155 lapua scenars with 47 grs of varget. (coal is 2.850) The powder is into the neck and the base of the long scenars are at the base of the shoulder. I can hear some of the powder crunch when Im seating the bullet.

other question is has anyone ever seen the compressed air in the case after seating, push the bullet back out? Not that im seeing it but just wondering.

 

[Mikem]

Well, I do shoot and reload for a 308, and I use a lot of Varget in it, but with 168g SMKs mostly. And with 44.5g of Varget the powder is about even with the bottom of the shoulder, but your loading 47g and a 155g bullet, personally I dont think that's too hard of a compression load. I neck size my 308 Lapua brass, so if your F.L. sizing, that may be why the case is as full as it is, but it should be fine.

Compressed air, enough from seating the bullet will push the bullet back out? You must have forgotten to size the case neck, its way to loose, and dont lube the inside of the neck.
If you do during sizing, clean it out. I use a little lacquer thinner on a bore mop, but any good solvent will work.
Mike.

 

[Laurie]

When it bulges the case shoulder or starts to push the bullet out of the case giving inconsistent COALs. Extruded powders don't seem to mind being broken up a bit, but it used to be said you should never over-compress ball powders as they rely on surface 'deterrent' additive coatings rather than physical shape to get the correct burning rate. Break too many little balls open and you change the charge characteristics and increase pressures.

Personally, I hate to hear and feel powder grains 'crunch' as you seat the bullet in very heavily compressed loads as in some magazine-length .223 Rem combinations with 69s, 75s, and 77s, so try and avoid the situation if I can. However, such 69gn loads in .223 always performed OK, except they sometimes pushed bullets out fractionally and caused magazine feed problems.

Your 308 loads will be fine. It may be worth getting a powder funnel with a six-inch drop tube - Forster does an excellent universal calibre model, and MTM does a plastic funnel kit with several tubes including one four or five inches long. If you pour powder into the funnel slowly and tilt it so the powder stream swirls around the funnel sides before entering the tube, this will compact the grains a little and likely see the top of the charge drop down below the shoulder-neck junction.

Laurie,
York, England

 

[alf]

Along with a longer drop tube and a slow drop, I sometimes use an el' cheapo metal engraver that vibrates to beat the band. One lap or two around the loading block settles the powder right nicely.

 

[CJ6]

+1 what alf said or turn the tumbler on hold case (finger over mouth thumb on base ) and just a touch on the tumbler will settle it (powder) right down.

 

[Ackman]

when is a compressed load too compressed?

Depends on the powder. How we used to fireform 22-250AI cases. Fill a new 22-250 case right up to the mouth with W760 powder then seat a 55gr Sierra BTHP....in my chamber it went probably 1/2way down the neck. It was a pretty compressed charge. Some people would dump in a bunch of powder and scrape it off flush......I'd set the powder measure to just slightly less than full and the charge was whatever it came out to be, usually about 41.3 or 41.4gr. I formed something like 1200 cases that way and accuracy was quite good.

In a .223, the most accurate 55gr. load with VV135 has the powder compressed about .100" or so.

 

[whiskey08]

ill try the drop tube and vibrate it down a little, I just didnt like the sound of the powder crunching. Sounds like it should be fine tho, thks for the replies

 

[clowdis]

I'm using 47 grains Varget in Lapua brass with the Berger 155.5 and the chamber that I have allows me to seat the bullet with the back of the boattail about even with the back of the neck. This compresses the load just a little bit but not excessively. If I remember correctly the Lapua Scenar seats a lot deeper into the case than the Bergers so you're probably compressing pretty hard. I also remember that the Scenars didn't need that much powder to work well, but to each his own. I'd have my gunsmith throat my chamber out a little bit more if the compressed load worried me which would allow me to seat the bullet out a little more. Another option is to try some Winchester brass which is usually a bit lighter and might allow a little more powder room.

 

[1000yardstare]

In F Class two years ago shot 107 SMKs out of a .243 Win using 46.5 gr RL25. Moderately compressed. Very accurate out to 1000 yards. Won several events with that Savage 12FV.

Wondered myself if over time the compression would start pushing the bullet back out. As previously stated, this would depend a lot on neck tension. Measured COAL on cartridges stored over a Winter and they measured the same as when loaded the previous Summer. Just as accurate. So my neck tension must be adequate.