powder crunch

[wjarrell]

Hey y'all, I'm still working on loads for my 260 rem. Criterion 24" match chamber 1:8 twist. 140 vld lapua brass and CCI 200 primers. I using H4831sc but without any published loads in the Berger manual for 140 I'm going slow. 44 grains gave me good accuracy, 44.5 and 45 opened up, no pressure signs. So today I loaded 45.2, 45.4, and 45.6, 5 of each. Powder crunch on all and it seemed that at 45.6 my bullet was slightly pushing out after seating, no more than .010 of and inch. My COAL is 2.900 right now and that is .022 off the lands.

Now what I should have done was shoot my 44 grain load that shot about .5 moa through the chronograph to see if I was getting good speed. If I got the speed I want with 44 grains (2650-2700) I would have stopped.

Is powder crunch ok and if so what about my bullet growth?

Can someone with quick load calculate what kind of velocity I would see with 44 grains of H4831sc using Lapua brass, CCI 200 primer and 140 vld?

 

[Gord0]

I don't mind a little crunching, but am not a fan of really compressed loads. It may be time for you to try a little faster powder if you're starting to get bullet push out. Bullets pushing out of the case just says inconsistent to me.

 

[MagnumManiac]

Hey y'all, I'm still working on loads for my 260 rem. Criterion 24" match chamber 1:8 twist. 140 vld lapua brass and CCI 200 primers. I using H4831sc but without any published loads in the Berger manual for 140 I'm going slow. 44 grains gave me good accuracy, 44.5 and 45 opened up, no pressure signs. So today I loaded 45.2, 45.4, and 45.6, 5 of each. Powder crunch on all and it seemed that at 45.6 my bullet was slightly pushing out after seating, no more than .010 of and inch. My COAL is 2.900 right now and that is .022 off the lands.

Now what I should have done was shoot my 44 grain load that shot about .5 moa through the chronograph to see if I was getting good speed. If I got the speed I want with 44 grains (2650-2700) I would have stopped.

Is powder crunch ok and if so what about my bullet growth?

Can someone with quick load calculate what kind of velocity I would see with 44 grains of H4831sc using Lapua brass, CCI 200 primer and 140 vld?

Bulky powders will always be slightly compressed, and the more you add, the more compressed they'll be.
I run 200gr Accubonds in the 300WM, it's such a long bullet it gives huge crunch with most suitable powders at near or max loads. I have to single load rounds if using Retumbo, otherwise the bullets back out overnight after seating!

The compressed loads are perfectly safe, if that is your concern.
Lots of powder actually burns better compressed than loose in the case.

Hope this helps.

Cheers.
gun)

 

[Buckskinner]

Bulky powders will always be slightly compressed, and the more you add, the more compressed they'll be.
I run 200gr Accubonds in the 300WM, it's such a long bullet it gives huge crunch with most suitable powders at near or max loads. I have to single load rounds if using Retumbo, otherwise the bullets back out overnight after seating!

The compressed loads are perfectly safe, if that is your concern.
Lots of powder actually burns better compressed than loose in the case.

Hope this helps.

Cheers.
gun)

I do the same thing, with the same bullet/powder in the 300 RUM. Why not put a bit of a crimp on it so it doesn't back out, and might just shoot a little better to boot...

 

[jimbires]

are you using a funnel with a drop tube ? this helps settle the powder in the case . I had this bullet growth problem before , I ran my ammo back through the seater die the next day and my bullets stayed where I wanted after that .

 

[Rymart]

Look up the 6.5 Guys video on this. They use a 'sonic care' vibrating toothbrush touching the side of the brass to help settle the powder. Surprising how well this works.

 

[Buckskinner]

Now that is a great idea!

 

[Frank in the Laurels]

A drop tube will solve your problem in a second... A little speed and gravity will pack it right in...

 

[jimbires]

I forgot in my other post . 44.0 grains should give you 2699FPS at 54441 psi ( 60191 psi is max ) and this is 103.8% case fill . at this case fill a drop tube funnel should be all you need .

45.3 grain would be max 106.8% case fill 2786 FPS 60368psi


for more velocity I'd be looking at RL26 , RL17 , RL16 these will get you into the 2825 - 2875 FPS range . with case fills of 97 % to 105% at max loads . I use RL17 in my 260

 

[wjarrell]

I forgot in my other post . 44.0 grains should give you 2699FPS at 54441 psi ( 60191 psi is max ) and this is 103.8% case fill . at this case fill a drop tube funnel should be all you need .

45.3 grain would be max 106.8% case fill 2786 FPS 60368psi


for more velocity I'd be looking at RL26 , RL17 , RL16 these will get you into the 2825 - 2875 FPS range . with case fills of 97 % to 105% at max loads . I use RL17 in my 260

Thanks for the info Jim, I might try different powders but I need to stick with a temperature stable powder.

 

[DocDoc]

RL-16 and RL-23, are supposed to be temperature stable like the extreme powders. RL-26 is fairly stable - mixed reports on how much it varies with temperature.