74A95 said:
It should be pointed out that QuickLOAD states: "WARNING! The data predicted by QuickLOAD CANNOT be used as a substitute for information gained from standard handloading manual references; . . . "
In other words, QL is no substitute for actual pressure tested load data, which VV has.
Which source would I trust? The VV manual.
Why did you ask me to take the time to put up the QL and GRT data if all you intended to do was dismiss it? I am puzzled by that. If you had bothered to read my original post #3, what I said was:
Unclenick said:
I note that in this case, both QuickLOAD and GRT think the VV maximum load is overpressure. They are computer models that can be wrong for several reasons, but I add this as a caution to work the load up in steps…
So, I presented the simulator output as one additional clue that the load should be worked up from minimum. I've been using QL for twenty years and made many, many comparisons of its output to published data that included both pressure and velocity and found that when the velocity is a match, the predicted pressure is virtually always equal or lower than the measured pressure due to modeling limitations. In this case, the pressure was high for the reported velocity, which I took as unusual enough to consider it a caution to work the loads up from the bottom.
So, the question is, do you actually disagree with the advice to work loads up from minimum? Every loading instruction manual I can recall reading, including those from the bullet and powder makers and distributors, has said to do this if you want to be sure to stay safe. And numerous folks, as the OP appears to have done, ignore it. And while one
usually has no trouble starting higher, every once in a while, it causes a problem. It is rare, but it's not zero probability, and expending half a dozen rounds coming up from the bottom eliminates the chance of it, so it seems to me to be a prudent thing to do.
We had a member a while back who was working up through 243 Win load data in the Speer manual, and a little over halfway to the top, his Handi-rifle was popping its action open on every shot, and the velocity he was getting was more than 200 fps above the published one. He knew the trick about checking the Handi-rifle catch for dirt and debris and had none, and he had no problem like this with commercial loads. So, he called Speer to report the problem. Their response was to tell him they had a ballistic technician's signed pressure test document showing the top load was within SAAMI limits. Period. Apparently, the lawyers have Speer's backside covered, whether it was covered by an error by the ballistic technician or not. Indeed, the lawyers might tell them that checking it out would be an admission of uncertainty which would leave them vulnerable to a lawsuit.
And it may not have been a ballistic tech error. Their lot of powder may have been slow compared to what is current. They may have used a higher capacity case, a milder primer, or all of the above. The SAAMI standard P&V test barrels use a nominal bore diameter, while the Handi-rifle may have had a tight bore. I've even seen a couple of guns with tight chambers and short "throats" because only the roughing reamer had been run into them at the factory and the finishing reamer step had been omitted, and those, if you can close the chamber on a live round in one at all, can jam bullets pretty hard in their "throats" and give you high pressures. Whatever the reason, and here is the point, the test was showing there was no safe way to get to the published charge maximum in that gun without the risk of gun damage or primer blowout or possibly even a cased blowout.
So, again, it makes sense to always work up from the bottom. It only takes one round at each step for a total of half a dozen rounds to have that safety assurance.
Reddog81,
We also don't "know" what the OP's guns are. If his Smith is an old aluminum frame Airweight, I would be very concerned about frame stretching on a steady diet at those pressures, as +P ammo is known to do it to them at just 20,000 psi max. If his Charter is the aluminum frame Boxer model, it's not rated for +P as their thicker aluminum frame 5-shot models are, so, again, I would be concerned about frame stretching in the long term if those pressures are right.
Regarding the crimp, what you advised the OP to use was a "light" taper crimp. I don't know if you have ever owned a light snub-nosed revolver, but with full-house loads, the lighter they are and the warmer the load, the more smartly they recoil, which means they try to pull the cases off the bullets. Heavy magnum loads can do this in heavier revolvers. As an extreme example, a friend of mine with a titanium cylinder 5-shot snubbie in 45 Colt cannot use even roll-crimped commercial loads with 250-grain bullets because that gun recoils so sharply that the bullets are inertially pulled and end up sticking out of the cylinder and jamming its rotation. He had to stick to 200-grain bullet commercial loads to reduce recoil enough to prevent this until we got him a Redding Profile Crimp die and put really hard roll crimps into his bullets. A Lee Collet-style Crimp Die might have worked, too, but while it is available in 45 Colt, it isn't available in 38 Special, so I can't recommend it to the OP. In neither case is brass life as good as it is with a taper crimp, but if you really need to hang on to a bullet, they work.
Taper crimps were devised to extend case life and make the crimp adjustment in rimless auto pistol cases less critical. Before taper crimps were common, one had to adjust the more abrupt roll crimp shoulder of a standard die to take the flare out of rimless auto cartridge cases without making them too narrow to headspace on the case mouth so case length consistency was more of an issue. Their availability for revolver calibers was probably based on making the exact case length and die setup less critical. I have used taper crimps with wadcutter loads in 6" target revolvers with no problem. But those guns are heavy, and the loads are light.
There are several ways you can prove roll crimps are harder to break loose than taper crimps are. One is to apply both crimp types to dummies and see which ones your inertial bullet puller can pop out more easily. The old-time bull's-eye shooters always reported roll crimps on 45 ACP rounds produced higher and better velocity consistency and accuracy than taper crimps. They were shooting tuned 1911s, so they had to seat the bullets out to stop on the chamber throat for headspacing, rather than relying on the case mouth to do it, but it worked for them, and you can find posts by bull's-eye shooters still doing it for the better accuracy. It shortens case life, but it works.
Another proof is to load up some magnum loads with 296/H110 and go to the range and look at how they behave over the chronograph and on the target to see if you don't get the same difference in velocity consistency and accuracy (though I recommend loading the taper-crimped rounds one-at-a-time to prevent pulling). That powder needs as much start pressure as it can get. Load them using the Redding Profile Crimp Die, and the consistency gets still better, as Phillip Massaro mentions in
this Gun Digest Article.
The Redding Profile Crimp is a funny combination of taper and roll crimp. It was observed long ago that there is a limit to how hard a standard roll crimp die can successfully crimp a case. This is because forcing the lip of the case mouth to turn its tight corner radius too far causes the sides of the case below it to be lifted outward, away from the sides of the bullet. This not only takes away from the grip case friction has on the bullet but, taken far enough, it can interfere with chambering. This happens because the die below the crimp shoulder has to be loose to accommodate different bullet and case tolerances. The Profile Crimp Die solves that problem by starting with a taper crimp that presses the brass against the bullet's sides before terminating in a roll crimp shoulder at the top of the taper. The tapered portion thus holds the sides of the case in place while the roll crimp is applied, preventing that outward lifting of the sides of the case away from the bullet.
I realize a roll crimp can crack and slightly distort the copper on a plated bullet, but it's better than jamming the cylinder and having to deal with safely getting it open when the protruding bullet is on the wrong side of the frame. The snubbie is not a target pistol, and any inaccuracy error introduced by that distortion will not be noticeable at practical snubbie ranges.