Is precision reloads on a progressive press possible?

[tobnpr]

I can't tell from the comment if you're skeptical that it works as claimed (my copy certainly does), or if you're skeptical that throwing by volume isn't superior to weighing when you are outside of controlled temperature and humidity conditions.

Weight vs. volume metering.
I get the fact that vibration (especially inconsistent vibration) of the meter confounds the process. I had huge differences in charges until I "beefed up" the mounting surface of my bench to minimize this. I get only one tenth variance now.

The Quickmeasure seems to tout it's worth based on not "cutting kernels"- which to me, is a non-starter. I've found that vibration/shaking is the enemy. With QM mounted to the press, I can't see how it provides any advantage. It's going to be subject to the same press vibration as the powder measure.

[reynolds357]

I dont know why Buck Rub. Why is my 6ppc more accurate than my 6 BR that is built out of much more expensive parts than the PPC? Some things in life are a mystery.

[Unclenick]

Originally Posted by tobnor

The Quickmeasure seems to tout it's worth based on not "cutting kernels"- which to me, is a non-starter. I've found that vibration/shaking is the enemy.

If you read the Design Differences, you'll find it's not the fact the kernels are cut that makes any difference. That would be silly to expect. It's the fact the act of cutting a kernel causes a sharp vibration (exactly what you are concerned with) that's the problem. Some time ago I verified that's real with both my RCBS Uniflow and my Redding BR-30. I did a series of measurements of throws with and without kernel cutting. Both measures would cut hard maybe once every third or fourth throw with 4895. By weighing the charges I found the cut charges themselves were just fine, but the next charge thrown right after a cut was usually high by an average of about 0.4 grains. Sometimes the second charge thrown afterward would also be high, but usually not as much. The small shock from the cutting action settles powder in the taper that funnels into the metering chamber, and it takes a couple of throws to clear that out.

If you are anchoring your current measure well and getting 0.2 grains, that's better than most people do. I expect you'd find the Quick Measure does even better under the same well-anchored circumstance. In a thread on another forum, board member Daboone relayed that he was getting 9 out of 10 throws from the Quick Measure dead on, then the 10th might be out 0.1 or 0.2 grains. That's pretty close to what I see. If I mount it to its plastic benchrest kit box, the throws are off more often, but still within 0.2 grains, which is what I would expect of it mounted on a progressive press. If I mount it on its solid stand, the throws tighten closer to what Daboone sees. So it's not totally immune to vibration, but is more so than most. That has to do with the right turn the powder makes filling the chamber.

Originally Posted by reynolds357

I know I have always gotten better accuracy from weighed charges than I have from volumetric charges when dealing with stick powder.

I would guess your powder's at fairly constant humidity and temperature. I think that's why weighing works for most people.

I just did the first weigh of my desiccating powders experiment and they are both down about 1% so far, and I haven't swapped out the desiccant for fresh, yet, so they're not as dry as they will be. A charge weighed now would have about 1% more energy (1% more actual powder compounds) than it would have had at the same weight three days ago. That's not a lot, but it's the same as increasing the charge weight 1% when the humidity is constant. Half a grain out of 50. Enough to move you off a sweet spot with a number of powders, though not very far off. Since the Quick Measure throws within 0.2 grains, or 0.4% of a 50 grain charge, it would now be about 2.5 times more consistent in throwing actual powder content of a charge, given the humidity differences conditions.

[Bart B.]

Reynold's delima:

I dont know why Buck Rub. Why is my 6ppc more accurate than my 6 BR that is built out of much more expensive parts than the PPC? Some things in life are a mystery.

They're not exactly the same. One's different than the other. What that is may be near impossible to discover.

One thing to check; the barrel's inside hole. Have it checked for bore and groove dimensions as well as uniformity of twist rate. One of them is not as uniform in at least one area than the other or its groove diameter is larger; it's probably the one that shoots least accurate. This (dangerously) assumes both rifles are built the same way. Most barrel makers I've talked with say non-uniform twist rate's the most often cause of poor accuracy when everything else is perfect.

Another thing to check. Are both rifles built on the same action? If so, are both firing pin springs still at the same spec preload force when the firing pin's cocked? If they're the same, then the least accurate rifle may well have a weak firing pin spring.

And finally, if both barrels have vastly different rounds fired, the one with the most will be less accurate. All barrels degrade accuracy starting with the first round fired. It's hard to tell for the first couple hundred shots, but it happens.

[4runnerman]

Hey Bart- correct me if I am wrong here,But a 6PPC is more accurate then a 6BR out to 300 yards, That is where the PPC fails and the BR starts to shine.

A 6PPC is not a long range rifle- The 6BR is.

[reynolds357]

Bart, they are both Shilen barrels. They were both built by the same smith. He re-barreled the PPC and built the BR from scratch. I cant swear they are both the same quality barrel, but they are both Shilen's highest priced barrels. The barrel on the ppc has over 2k rounds on it. The BR has less than 500. The BR is a Bat action. The PPC is built using a sleeved 700 action. The Bat should most definitely be the better action. The 6 PPC was a 6x47 in its former life. (tells you how old it is
Dont get me wrong, the BR is by no means a dog, but its just not quite on par with the PPC.

[Bart B.]

Reynolds, there's a difference someplace between them. I only suggested where one or more might be.

No high end barrel maker's barrels have zero tolerance in all dimensions. Nor does a given 'smith's chambering and fitting process. So, without finite detail measuring of all things relevant, one's limited to guessing why one's more accurate than the other without any facts to base their decision on.

For all I know, you may be loading one's ammo to better quality than the other.

[reynolds357]

The possibility definitely exists that I have never found the perfect load for the BR. The PPC was a shooter even when it was a 6x47; not Lapua, but the old 6mm x 222 rem mag. The PPC is an ugly rifle. The bolt has so many holes drilled in it that it looks like the termites got it. It still has un-painted bondo from my last stock modifications. I plan on painting it John Deere Green, but have not got around to it yet
Building bench guns is past my abilities. I can build good hunting rifles, but I do not deceive myself to the point of believing I could build a winning BR rifle.