40-grain Varminator Load Data

[Tdk1098]

Hello, I started reloading for a couple of my .223s a few months ago and recently picked up some 40 grain Barnes Varminators to try out in my Savage. Unfortunately, I can't seem to find any data for these projectiles and CFE223 or Varget. Does anyone here have access to (or at least know of) a reloading manual with maximum/minimum charges for either of these two combinations? Lyman 49th and the Hodgedon website don't seem to have anything on them. If nothing else I can buy a different powder, but I would prefer to keep the number of powders I have on hand to a minimum.
Thanks!
-tdk

[Unclenick]

Those powders are too slow for a bullet that light. That's why you don't see data. When a bullet is too light for the powder, it runs away from the case so fast a slow powder can't make gas fast enough to keep up with it. The result, at best, is disappointing velocity and a lot of powder being thrown out of the muzzle unburned. The powders you mention really work best with 69 grain match bullets and heavier, IME.

The worst case scenario is that a funny secondary pressure can develop when bullets are too light for the powder burn rate. Gas columns in barrels don't make a uniformly distributed pressure, and drops a bit behind the bullet. If the bullet is there long enough, the higher pressure zone throws a pressure front up against it that reflects up and down the bore and it can double up making additive pressure very high as the zones pass through each other. Normally, this is an artillery issue, as in small arms as the barrel time is typically shorter than the resonant frequency of the waves. However, when a bullet scoots away from a powder too fast, it is possible for pressure at its base to drop an unusual amount, letting the bullet slow down, thereby lengthening barrel time enough for a pressure wave of gas to create the high pressure nodal additive condition. Texas gunsmith Charlie Sisk has blown muzzles off 338's with a particularly bad combination. It can take a dozen shots, but the barrel bulges down near the muzzle and it happens at a consistent location, so it finally bulges enough to develop cracks and lets go.

This is not always happening, but you have to be aware it can occur when you start messing with inappropriate powder burn rates. I would recommend you look at Reloader 10X, which is made specifically for light bullet use.



Even commercial loaders can mess up sometimes:

[Tdk1098]

Oh man... That's definitely good to know. I was hoping they would work since I had gotten some pretty good results running 69 grain SMKs over both powders. I'd been told by a CS representative at Barnes that both of those powders would be good choices for the lighter Varminators, but I'll go ahead and pick up some RL10X anyways. Call me crazy, but I prefer my rifles in one piece. 104,000 PSI? Yeah, that's definitely messing up... Thanks for the heads-up.

[old roper]

Best place to look for data is Barnes site and they have that bullet listed

http://www.barnesbullets.com/files/2...compressed.pdf

[Tdk1098]

Thanks for the link. It looks like Reloader 10X is their recommended powder as well. That'll definitely be my first choice.

[Unclenick]

The traces you see above are strain gauge readings, which measure the actual deformation of the steel. When a pressure event happens that is local to a particular position in the barrel that is not the chamber, it is invisible to a piezo transducer or a copper crusher. The strain gauge picks it up because the steel expansion at the site of the event (usually down nearer the bullet) reflects back as along the steel. That's why you could see it in the commercial ball ammo. The maker, using a transducer, never knew it was there.

By the way, as high as those pressure spikes are, barrel steel can withstand a lot. Hatcher turned down a .30-06 barrel, including over the chamber, to a thickness of 1/16", and it still fired service ammunition just fine. He did blow it up with a high pressure "blue pill", however. He said these measured 75,000 CUP. It has been learned since, that copper crushers are so non-linear in the high range that this probably would have been about 125,000 psi (extrapolated by logarithmic curve fit to the plot on page 43 (Acrobat page 54) in this study). That said, in the second half of this paper, Ristow describes an AR barrel that was ringed by it over time. His theory of the cause, though, seems less likely to me than the known gas waves found by military research on artillery.