Loading HV long range .308 cast bullets
- Thread starter waco
- Start date
fiver
Well-Known Member
http://www.ballisticproducts.com/Buffers-Mica-Wad-Slick/products/72/there are a couple of types and sizes it's basically an inert plastic, poly, or mica based spherical filler.
it does a couple of things.
it boosts the load by making it think the case is full [good for some powders]
it protects the base of the bullet.
it helps control gas cutting.
it provides a bit of cushion from the primer shockwave and gas pressure on the bullet.
even a small amount is a big help, actually a small amount is the best application.
it also just poofs off into the wherever at the muzzle without creating a problem.
fiver
Well-Known Member
or lee scoop it's a volume thing.
you fill to the base of the bullet plus a titch then compress lightly almost like a 103% load.
so you'd try a say .2cc amount and look at your mark of where the base of the bullet seats and then a .25cc etc. your basically eyeballing the first bit then feeling the seating then settling on the amount.
it just sets everything in place.
then you can try different primers to tune the load a little more.
you fill to the base of the bullet plus a titch then compress lightly almost like a 103% load.
so you'd try a say .2cc amount and look at your mark of where the base of the bullet seats and then a .25cc etc. your basically eyeballing the first bit then feeling the seating then settling on the amount.
it just sets everything in place.
then you can try different primers to tune the load a little more.
Ian
Notorious member
No.
How you use it depends specifically on which buffer you use. I ONLY recommend this stuff right here, which is a shredded/granulated stuff that does not flow like BBs, it clumps and packs together under pressure: https://www.midwayusa.com/product/695248/bpi-shot-buffer-original-500cc-approximately-1-2-lb
Your current load is actually pretty much perfect for this kind of buffer, but you need to make certain you understand how it works and what you're trying to achieve with it. Just dumping it in and hoping won't get you very good results, and can raise pressure dangerously if you use too much or use it in the wrong way.
What you want to achieve with the compacting, granulated stuff is a solid, plastic wad behind the bullet which does the things Fiver outlined above. To do this, you need the correct amount in the case, and it needs to be at the right density before firing.
Generally, you need a slightly slow-for-cartridge powder, such as what you're using. Establish a good load near where you want to be, as you've done, with powder volume approaching the base of the neck, and still have a safety margin for pressure, which you've also done. Then you have a load you can reduce volume-wise to make room for the buffer. If you reduce powder and add buffer the way I explain, the velocity will be about the same as before you reduced the powder.
In the .308 case, buffer does its magic when the powder level is right at the shoulder/body junction (less than you have now) when the case is gently tapped with a pencil to settle the charge to that point. Never build a load with buffer where the powder is more than 1/16" below the shoulder/body junction, understand? Too much buffer creates an obstruction behind the neck (remember, the buffer plug is taking all the force of engraving the bullet), and very quickly will spike pressure. I have seen photos of a cartridge missing the shoulder part forward where buffer tore the whole mess off and shoved it through the bore, NOT good. This mishap was caused by powder being about 3/8" below the shoulder/body junction when buffer was added.
Your IMR 4831 load should be reduced to settle in at the shoulder/body junction inside the case, then a powder funnel installed over the case mouth, and buffer sifted very carefully into the case a pinch at a time between thumb and forefinger until it comes up in the neck the thickness of a gas check higher than the bullet base will be when seated. That amounts to a little over 1/16" compression when the bullet is seated, you do not want any more than that.
There are little smoke plumes going up all over the country right now, so before anyone has a stroke, I will mention that I learned how to do that from 45 2.1, in a post long ago on the CB forum, so remember to give him all the credit.
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Ian
Notorious member
Naw, differerent stuff, the kind I showed is cheaper....
I've used puff-lon and the spherical BPI stuff, both have their place but not for this IMO. The "Original" like you and I both linked is a whole different animal. Your saying "103% compressed" sounds spot-on to me, that's about what it ends up for me and the target tells when you got it right.
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F
freebullet
Guest
Your doing some really nice work, waco. Thanks for sharing.
waco
Springfield, Oregon
Well thank you for the kind words. It's a work in progress and I couldn't do it without all of the help I have gotten from
Fiver, Ian, and Brad. Credit where credit is due.....
waco
Springfield, Oregon
I have often thought how cool it would be if we could just all hook up for a long 3-4 day weekend to shoot and BS. Get to meet one another face to face. Would be good times.....
waco
Springfield, Oregon
I might be able to swing that....
