Pressure Signs?

[Mikecr]

Bore Area is one of the QL adjustments. There are many ways to calibrate QL.
People just need to understand that until something is calibrated, it isn't.
And consider this: reloading manuals cannot be calibrated.

 

[Rich Coyle]

I fired some rounds of my .220 Extremist from the same box of cartridges in two rifles. One was a 26" factory Savage with no change except the reamer run into it. The other was a 30" Pac-Nor. Firing Nosler Ballistic Tip 55 grainer the Savage averaged 4,005 feet per second. The Pac-Nor averaged 4,300 feet per second.

When I had a Freedom Arms .454 it ran 100 feet per second slower than any others I read about. I figured that's just life.

My .270 Win is using 2.2 grains below what Barnes told me on the phone to use for max and yet my velocity matches their max load. Interesting thing about it is the 63.5 grain load they came up with for an accuracy load is what I discovered is my accuracy load. I didn't know it until I finalized the load and someone told me.

 

[RockyMtnMT]

Bore Area is one of the QL adjustments. There are many ways to calibrate QL.
People just need to understand that until something is calibrated, it isn't.
And consider this: reloading manuals cannot be calibrated.

Right. So the guys that are saying QL says he is way over pressure have not calibrated the bore dia?

Steve

 

[Pdvdh]

And consider this: reloading manuals cannot be calibrated.

Good one.

 

[Mikecr]

Right. So the guys that are saying QL says he is way over pressure have not calibrated the bore dia?

Not motivated to feed an appeal to extremes instigation right now.. But you can reason through what I said earlier and play with it in QL.

You can see in QL that bore area is different from one cartridge in cal to another in the same cal.
Bores vary(various land/groove configurations), and bullet diameters vary, and powder doesn't meet standards with any precision. Our seated starting pressures, and load densities, capacities, and weighting factors are different.

QL has a couple good readme files to get a feel for it's accounting of all these adjustments. When you learn the software and use it for a while, you see the absurdity in notions of 'accuracy loads' claimed for a cartridge,, even before considering the abstracts added in actual load developments.
There is no predicting of what you hold -vs- what I hold.

 

[RockyMtnMT]

Not motivated to feed an appeal to extremes instigation right now.. But you can reason through what I said earlier and play with it in QL.

You can see in QL that bore area is different from one cartridge in cal to another in the same cal.
Bores vary(various land/groove configurations), and bullet diameters vary, and powder doesn't meet standards with any precision. Our seated starting pressures, and load densities, capacities, and weighting factors are different.

QL has a couple good readme files to get a feel for it's accounting of all these adjustments. When you learn the software and use it for a while, you see the absurdity in notions of 'accuracy loads' claimed for a cartridge,, even before considering the abstracts added in actual load developments.
There is no predicting of what you hold -vs- what I hold.

I wasn't trying to cause a problem. My point is that at the beginning of the thread guys were making the op sound like he was defying death. I don't know if it is that bad. I think it is a pretty good sign of pressure if the vel is too high. No doubt.

Probably a good idea to back off a bit. I never did see what chrono is being used.

Steve

 

[Bowfishn]

I wasn't trying to cause a problem. My point is that at the beginning of the thread guys were making the op sound like he was defying death. I don't know if it is that bad. I think it is a pretty good sign of pressure if the vel is too high. No doubt.

Probably a good idea to back off a bit. I never did see what chrono is being used.

Steve

Makes no difference to me what someone wants to use for a load, without knowing his exact set up QL cannot be used to give an exact figure. My figure given were generic based of the 48 gr H2O case and 2.80" COAL, I am pretty sure QL used Lapua Cases so other than lot differences and actual chamber size 48 H2O should be close.

But there is no free lunch, either the chrono is off or factors are increasing pressure to increase speed, jam the lands increase pressure increased speed, tight bore increased pressure increased speed, low case volume increased pressure increased speed, powder burn rate high on lot increased pressure increased speed, extreme temperatures equal higher pressure and increased speed. There are also other factors that increase pressure and thus increase speed.

Point being to get extra speed with a certain powder you need to increase pressure, small percentage increases can be gained by using friction reducing coatings and increasing powder charge, seating longer without jamming lands if you have a long throat, then again adding powder charge. Using a case that has larger volume and then increasing powder charge. But none of the methods I believe will get you 100 fps and still stay within Cartridge Published Pressures.


Ran some new figures with a few tweaks to see what QL shows could be achieved by some using of the methods above.
If you could increase COAL to 2.890" without jamming lands and if your case volume was actually 48.5 gr H2O and if you used a coating such as HBN or Molly on your bullets 3006 fps could be obtained by 70,633 psi according to QL. Those tweaks dropped pressures listed by QL about 3,000 psi.
2.90"coal 49 gr H2O use the max increase shown in QL for friction proofing using coatings of .4 that would bring it to 69,209 psi

 

[Mikecr]

The friction proofing only works with moly. This, because it actually has nothing to do with friction.
Moly reduces pressure through latent heat of vaporization.
The other common coatings do not provide this, and they do not affect MV, or barrel timing.

I've tested this pretty well with my use of tungsten disulphide(WS2). This is far slipperier than moly and does not change MV or tuned load results over uncoated bores/bullets. I can go back & forth at will.

 

[Bowfishn]

The friction proofing only works with moly. This, because it actually has nothing to do with friction.
Moly reduces pressure through latent heat of vaporization.
The other common coatings do not provide this, and they do not affect MV, or barrel timing.

I've tested this pretty well with my use of tungsten disulphide(WS2). This is far slipperier than moly and does not change MV or tuned load results over uncoated bores/bullets. I can go back & forth at will.

Interesting, what about HBN?

I have some about a 1/2 oz of .5 u micron of the Hexagonal Boron Nitride I may give a try and see how it effects velocity. I will just do a few and check velocity for a base line.

 

[Bowfishn]

Just tested out my first batch of HBN with 142 ACLR and 130 ELD-M bullets. Velocity dropped enough it took .5 gr more of the RL26 to equal velocities recorded previously with those bullets. The ambient temperature was warmer today by a few degrees than the testing with out HBN. So what I found was it does reduce friction in the barrel reducing pressure.