Thursday - August 20, 2009

.45-60 Project, part 4 I think

In which Drew and Doc spend an afternoon sweating buckets, while using lead to shred 100 pounds of newspaper in the backyard. And great fun was had by all.



Spent some time this afternoon with Doc and his Uberti 1876 Winchester reproduction in .45-60. He came into a Dillon 550 press for just about free, so I’m teaching him how to reload.

Today we made ammo with the components he had on hand, plus fired off a few rounds I’d made him several months ago.

He had Reloader 7. In a round silver paper can. How old is that? It’s been in a black plastic jug ever since I’ve been rolling my own. But it was a sealed can before today, and the powder still worked, mostly.

None of the loads we tried today exceeded a calculated pressure of 27,000psi on the QuickLoad software, which is less than the rated pressure for this rifle, and none of them met the expected velocity either. Which leads me to believe that, as usual, QuickLoad generates pressures and velocities on the high side, for safety reasons. We were probably in the 20-22,000psi range.

Using Starline brass, with the rims thinned to 0.063” and the cases cut to about 1.89”, we loaded the Meister short nose 300gr cast bullet. That’s the one with 2 small crimping grooves. Seated to the rear groove it functions through the action with no problems at all. This gives an OAL of 2.239”, a hair short of the maximum 2.25” length.

Loads were of older Reloader 7, with charges going from 38 to 43.5gr, and average (6 shots each) velocity from 1733 to 1933ps. That’s from the Uberti’s 28” barrel. No pressure signs or even the slightest difficulty in extraction.  THIS LOAD DATA IS NOT FOR ORIGINAL WINCHESTER RIFLES, NOR FOR ANY OTHER BRAND OF REPRODUCTION 1876 RIFLES. Actually, I won’t be using any of these loads either. They went off, we got good velocities, but the shot to shot variation was too large. These are NOT GOOD LOADS. DO NOT USE THEM if you want any kind of repeatable accuracy.

But he only had Remington 9 1/2 Magnum primers, which he neglected to tell me! Velocity variation was pretty awful, varying from 90 to 124fps per 6 shot batch with these loads. Was it the primers or the powder? It could be either.

Magnum primers give much larger velocity variation than do regular primers. And they are totally unnecessary in a case as short as the .45-60.

Even the largest charge of Reloader 7 we used came nowhere near being a 100% density charge. Lower density loadings often have more velocity variation. Plus the Uberti has a small throat in the chamber. This means that the bullet can move about 2/3 of a diameter forward before it engraves itself on the rifling. I have a personal theory that this is the actual effective length of a cartridge, because before that the bullet has no real resistance against it, and you can’t build up pressure behind it (and thus get a clean powder burn) until such resistance happens. So this travel room equates to even more unused interior volume, which lowers the actual load density, which in turn can lead to even more velocity variation.

A “magic load” would be about 104% density, either settled or slightly compressed, so that on ignition it was still over 95% density at the bullet’s engraving length. This situation doesn’t really happen with modern bottlenecked cartridges, only the older straight walled ones. In a bottlenecked cartridge, (and the steeper the neck angle the more this applies) the bottleneck causes the igniting powder to swirl within the case, burning there all nice and dense, instead of being blown down the barrel before it gets fully ignited, as is often the case with straight cases. While most pistol cartridges are straight walled cases, they are comparatively very small, and they use much smaller amounts of powders that burn much, much faster, so this situation doesn’t really apply to them either. But large charges of slow powder in a big straight rifle case will often take 4” to over 12” to burn properly. And with a repeating rifle like this one, you can’t just seat the bullet to a longer length. The cartridge has to be kept short enough to function through the action. So it’s a challenge.

This project is even more of a challenge, since a) very little smokeless powder load data exists anywhere for this old black powder cartridge, and b) what little smokeless data there is, is for original rifles which are precious antiques by now. So those loads are little popgun rounds, which still manage to match the anemic original black powder velocities of around 1250fps. There is one person - ME - actively trying to develop modern loads for this modern version of an antique rifle and cartridge. But hey, that’s the same thing I’ve been doing for a decade with my .45-70, and I’ve been pretty successful at that.

I had some rounds I had loaded with 40gr of new Reloader 7, behind the Cast Performance 300 GCPFP bullet. Seated to it’s crimp groove, this round is too long for the action at 2.32”, but it single rounds hand feed just fine. And my loads used either CCI or Federal regular primers. These loads averaged 1850fps, but had a 80fps spread from the 6 rounds we fired. Not great.

The last ammo I had for him used the same Cast Performance bullet, same length, but 49gr IMR3031. 5 rounds. The first 4 were all within 15fps of each other, averaging 1875fps. Round 5 went 1812fps, throwing off the variation of the whole batch. Was that an anomoly indicitave of a bad powder choice, or did I use a slightly lighter charge? I don’t know. I try to weigh each charge to well within a tenth of a grain, but I’m not a machine. And a small breath of air or a small temperature change can throw off the scale’s reading. You do your best, but shit happens anyway.

So we learned several things: the new .45-60 from Uberti is a great rifle, though it’s very heavy. It’s toggle link action is at least strong enough for rated pressure loads. The .45-60 in a modern proofed rifle is easily the equal of the .454 Casull or .450 S&W lever guns, and encroaches on .45-70 factory ammo specs. Reloader 7 is not the right powder. IMR3031 might be better. Next powders up will be Norma 200, Reloader 10x, Ramshot X-Terminator, and maybe BLC-2. We’ll try a little faster, a little slower, and see what happens. If I could lay my hands on some XMR 2015 - the stuff is really hard to find lately - I think that one would be just about right.

We fired the bullets from 10-15 feet, across the chronograph and into bundled dry newspaper. The Meister bullets penetrated about 2 feet of that but then shattered. SHATTERED. Into dust. Way too brittle an alloy. The Cast Performance bullets drilled right through 3+ feet of newspapers and magazines, and kept right on going. Though to be fair, by the time we got around to shooting them, the paper was pretty chewed up. So who knows? But they shot right through all of it. Good thing the rifle was pointing towards a patch of woods.

This was my first time shooting into dry newspapers. They get hot! Put a few 300gr bullets into them and the papers are hot to the touch. And utterly destroyed too. We turned 100lbs of newsprint into confetti, just about. Fun! 45 caliber bullets like these chew a hole into newsprint nearly as big around as your forearm. Easily 1 3/4” in diameter. That’s a damn big bullet hole.

Posted by Drew458     on 08/20/2009 at 10:38 PM   
Filed Under: • Guns and Gun Control •  
• Comments (1) • Trackbacks(0)  Permalink •  

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