Compressed Loads

[CVO]

Exactly what effect does this have on the case and the bullet?

The reason I ask is, because I just loaded some 155 Lapua Scenars with 45.8 grains of Varget, you could feel the slight resistance and hear the faint sound of the powder being compressed.

It was my understanding that 47.0 grains is a compressed load.

My load specs

Lapua brass 2.005 factory new
Varget 45.8 grains
OAL 2.81
155 Lapua .308 Scenars
CCI BR

 

[Thud]

Re: Compressed Loads

No real base effect. Need to watch pressure. The best way to prevent a full case of powder is to use a LONG drop tube for the powder. It lets the powder fall and distrubite its self evenly and stacks the powder evenly. A short drop tube just dumps the powder fast and doesn't let it stack evenly. Hope this helps

 

[19Scout77]

Re: Compressed Loads

You can also tightly tap the side of your reloading block shaking the cases slightly and the powder will settle considerably---just don't hit it so hard you spill the powder!!

 

[Thud]

Re: Compressed Loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 19Scout77</div><div class="ubbcode-body">You can also tightly tap the side of your reloading block shaking the cases slightly and the powder will settle considerably---just don't hit it so hard you spill the powder!! </div></div>

If you do that keep your finger over the case mouth..

 

[CVO]

Re: Compressed Loads

Thanks guys, I am using a short drop tube.

 

[Victor N TN]

Re: Compressed Loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CVO</div><div class="ubbcode-body">Thanks guys, I am using a short drop tube. </div></div>

Turn the handle VERY very slowly. That will have the same effect as the long drop tube. (Although I DO use a long tube myself. I also drop the charge slowly.)

Some powders actually work better with a full case load. Most accurate powders work better at 80%+ fill of the case. That holds the powder in place for the flash to ignite the powder column more uniformly. Compressing a charge is OK if the pressure doesn't get too high. A lot depends on the burn rate for that powder. Just watch and make sure the bullets don't start oozing back out. They will do that after a certain point of over filling.

 

[Grump]

Re: Compressed Loads

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Just watch and make sure the bullets don't start oozing back out. They will do that after a certain point of over filling.</div></div>

That's also a good way to ID which cases lost their neck tension or are too thin. I loaded some match .223s for my son (Varget and 77-gr) and was perplexed to find that a few weren't mag length any more.

 

[sp388]

Re: Compressed Loads

I load varget to 46.3 grains in lapua new brass for use with 155 scenars. My OAL is plenty big enough at 2.910 - so there is no obvious crunch or compression that I know of with this powder charge....

That being said is there an advantage of loading varget compressed.

Another posting here mentioned something like more consistent ignition but of the bullet isn't sitting on the powder (after it is compressed) then won't the powder just loosen itself back up when the casing is handled or thrown into your pack or whatever ???

How much of a difference in accuracy or SD/ES speeds is there going compressed versus non-compressed

 

[stephenmaturin]

Re: Compressed Loads

The best loads with 155gr Silver Scenars for me have been, 45.5gr of N-140 and 46.7gr of N-150 both compressed charges in Lapua brass, very accurate for my TRG. Better the N-140 but near. Perhaps compressed could produce primers fails if the burning rate is slow for the caliber.

 

[MontanaHick]

Sorry to drag an old thread up from the depths, but I'm facing a situation where I'm going to need to run compressed loads in my gas gun... What percentage of compression is safe before you start breaking kernels of double-base powder and effing up your burn rates (double base powders having burning retardants on the surfaces of the granules to adjust the rate of ignition, AFAIK)?

 

[P7id10t]

If it's a gasser, presumably a shorter barrel (18" or less) -- will you burn all your powder before the bullet leaves the muzzle? Curious as to why you need to run compressed loads, and on what caliber.
I find RL17 with a 200gr pill is compressed at ~46gr. What are you running? Also, because the slower powders are longer pieces of extrusion (at least the ones I use), I find putting my finger on top of the case and tapping it on the loading table before seating my bullet can settle the powder in the case from mid neck down to the neck/shoulder bend or a little more.