Compressed

[ricky5042]

Hi all does anyone know if compressing the powder is ok or not ok?
Thanks

Rick

 

[Laurie]

Within reason, it's fine. If too much, you have trouble seating the bullet and will break up some powder kernels which affects their burning rate. Some cartridges / loads nearly always involve a degree of compression - eg 69gn bullets in .223 Rem seated to magazine length COAL of 2.25-2.26" with a full pressure charge of suitable powders like N140 and Varget.

 

In other cartridges / combinations, excessive compression is a symptom of a poor powder choice - ie it's too slow and therefore needs an overly bulky charge to obtain normal pressures and velocities.

 

Black powder and Pyrodex charges should always be compressed to burn consistently.

[farmer7]

A bit of compression is absolutely fine.

[Wildcat69]

Depending how long your freebore is, this will determine your case capacity when measuring a standard length from the lands. If these 2 are of a good match then you can maximise power load without great suffering of pressure signs. I.e my ftr load for 185gr LrBt is 46.9 of N150 at 10 thou jump and I have no strong pressure signs although the case gets a reall battering . I had to bring my rifle to get the throat reamed as I couldn't get the desired velocity with the particular bullet without suffering from strong pressure signs.

 

But as Laurie explained too much is not good either as you will not get your desidered seating depth, good way to found out is by using a harbour press, you can feel and hear the kernel crunch is excess or not.

[ricky5042]

Hi all the bullets im using are Lapua 155gn scenars and they are longer than the sierra 175gn bullets I was using I am loading the oal 2.800" to start with and see how they do. Mark helped me measure to the lands the other day so once im done with the 2.800" il load them 10thou off the lands and see how that goes and by doing so they will be seated further out.
My last test with the elcho 17 saw me up to 48gns with no pressure signs and my new batch iv loaded them up to 49.5gns 5 at 48.5gns 5 at 49gns and only 2 at 49.5gns but I will do as I usually do and that's fire 1 check for pressure signs then carry on checking every other shot, I don't advocate loading this high so please do your own tests.

Rick

[Wildcat69]

What setup do you have? Have you measured your MV?

[Laurie]

My last test with the elcho 17 saw me up to 48gns with no pressure signs and my new batch iv loaded them up to 49.5gns 5 at 48.5gns 5 at 49gns and only 2 at 49.5gns but I will do as I usually do and that's fire 1 check for pressure signs then carry on checking every other shot, I don't advocate loading this high so please do your own tests.

 

Rick

 

 

Rick,

 

Elcho / Alliant Reloder 17 (same thing) is too slow burning for 155s. It's a powder that needs to run at close to full pressures to perform consistently. With a 2.900-inch COAL assuming that's around where you end up with the bullet just 'out', 100% fill-ratio is achieved at ~47.4gn with Lapua brass in a tightish chamber. That charge only produces 50,000 psi according to QuickLOAD.

 

You'd need to break the 50gn mark and see pretty marked compression to reach 308's maximum SAAMI pressure. My own experience with Re17/E17 is that it's not ideal for the 185gn Berger even, and needs to go up to the 200gn and heavier mark for it to perform well in the cartridge.

[Wildcat69]

Rick,

 

Elcho / Alliant Reloder 17 (same thing) is too slow burning for 155s. It's a powder that needs to run at close to full pressures to perform consistently. With a 2.900-inch COAL assuming that's around where you end up with the bullet just 'out', 100% fill-ratio is achieved at ~47.4gn with Lapua brass in a tightish chamber. That charge only produces 50,000 psi according to QuickLOAD.

 

You'd need to break the 50gn mark and see pretty marked compression to reach 308's maximum SAAMI pressure. My own experience with Re17/E17 is that it's not ideal for the 185gn Berger even, and needs to go up to the 200gn and heavier mark for it to perform well in the cartridge.

I agree with you Laurie I have tried RL 17 for 185gn and never got the performances that I would with N150, it's too slow burning. Also N150 burns much cleaner in the barrel.

[ricky5042]

Hi Wildcat69 mine is a howa 1500 24" 1-12 I don't know the velocity yet as im doing that on Wednesday with the load test.

Laurie that's what I was wondering but I keep getting told it will be fine for the 155gns but once iv run out I will get the TR140 as it seems to be more suited to the 155s from what iv read.

I will let you know you know how I get on after my testing and if my f1 crono works ok I will have velocities as well.

 

Rick

[Wildcat69]

Worth comparing different loads with different powders, you'll see the difference.

Good luck.