Pressure from base loads in Quickload

[DLJ6]

I realize it is no help to the OP but just leaving it here for the record/info. Back in the '90s I successfully used the case dimension/"drawing" function of "Load from a Disk" for use with my wildcats. We were doing single radius neck shoulder interfaces that I could not input but used a comparable angle. I had no way to verify pressures but the mv came in very close to the software predictions. Once the case dimensions were input I would tweak them until the predicted case capacity of H2O matched the actual measured value. For a relatively simple program it worked very well for me. I kept an old GW2k desktop that I still run the software on.

 

[cajun]

It will would probably surprise people to know that a lot of the bullet company data is not pressure tested. If you don't like quick load don't use Berger data. Powder companies like Hogdon do and they list the pressure with their data. This is why more often than not their data listed is slower.

 

[floyd kittrell]

I will personally NEVER use V V N 550 again due to the major swings I experienced over l2ess than 20 degree temperature variance . I learned , the hard way !! JMHO , You may want to check the V V N 565 powder instead, BUT, I have not loaded the 565 yet, I have read about it and it is SUPPOSE to be more Stabil , temp wise . Just a suggestion, I do not load the Sherman !

 

[Ronald W Schaefer]

I'm loading 300 Sherman, Fed210M, Starline brass, N550 and CEB Maximus 165's.

I'm seeing pressure like flat primers, high velocities and such at a load that Quickload shows 52000 psi. What the heck? Nothing is customized from a powder perspective yet. Why so many pressure signs at a base setting? Literally what say it should be 52000 psi is actually ~70000psi! Velocities were also consistent with max pressure predicted velocities.

I'm going to redo my ladder to end below this charge!

Are you seeing this? Is it the copper bullets maybe? I'm thinking I'll just start lowering my ladder start pressure to a predicted 45000 psi in a 65000psi gun.

….or is this somehow related to the Winchester 70 action?

Btw, never seen anything like this with cup& core bullets and Hodgdon powders with Quickload.

It could be The number of friction bands is not enough. Long bullets with a long bearing surface need more cuts than shorter bullets to keep pressure down.

 

[slikmrc]

….but how would you know that? 30-06 is 62-65gr of capacity…vs 75.2gr for 300 Sherman. Nosler showed 300 WSM as 66.1-76.0gr of water.

If I recall, 300 sherman is based off 270 win case. So you are basically creating a 30 by 280 Ackley improved. If your getting your volumes off of Nosler data, the volumes are bullet weight specific. Take a look at any cartridge in different bullet weights in there data. Using Vihtavuori 30-06 data would have worked and got you to a starting load were your currently are at 49 to 55 grains of powder. Checking volume between your parent case and a fire formed is a good idea also.

 

[Dan_351]

The 30 Gibbs is an improved 06 case? could that be closer and a similar case shape to the Sherman...

Secondly, considering the popularity of the Sharman in the US, Do they not have something or someone else that has posted result before.

As mentioned above the 30-280AI has been a better improved case over the 30-06AI due to its shoulder body and longer neck?


I am yet to test this LD out but finding a very safe charge and shooting 1/2gr increments over a Chrono to note velocity and inevitably find your pressure signs.

 

[300RUM LNGRNGE]

I have no experience with QL or N550 and almost no experience with CEB. I also have no metallurgy degree.
I type this , only to give insight into one of the OP's original questions.
I have had experience with solid copper bullets, Barnes to be exact, but would expect CE to react somewhat similar.
I loaded a 300RUM with Barnes 175 gr. LRX , Retumbo powder and CCI 250 primers and was only able to push these 3080 fps safely and accurately. Ran , suddenly, into pressure signs just over 3100fps.

Loaded the exact same rifle with the exact same brass , primers and powder, but switched to the Hornady 200 gr. ELD-X and was safely able to push them to 3216 fps. Group started to open up so I never tried to push them harder to see how fast I could get them.
Since the only component I had changed was the bullet and that the lighter bullet was slower, that lead is softer than copper, I deduced that bullet construction was probably the reason.

Have a friend loading Barnes into his 300RUM as well, he found safe velocities approx. the same as I had.


Hope this is useful.

 

[Darkker]

I get your dismissive post and all the shade you are throwing at QL, but the question remains.....

QL is not some kid with ice cream on his face. It is a simulation based on cartridge parameters and powder parameters.

My post wasn't dismissive, unless you won't jet fo of some bizarre hero worshipping. It was explanatory, to your original question, about why reality and QL didn't match.

QL is a kid with Ice cream on his face, because very few who use it, don't understand what it actually is. How many people have told you false information? "Uhhh... Change start pressure.....uhhh, change twist rates...".

Powder burning rates change with pressure and volume. "A" simulation based off fixed values is moronic, if you want to actually know what's happening; which per the point of the thread, you did. If you want to guess a start charge, without paying $300. To then attempt to justify why you paid someone else to make a guess, then compare volume and expansion rates. Volume to bore is how it's been done, and why the Creedmoor and 30-06 take extremely similar powders(not progressive).

It could be The number of friction bands is not enough. Long bullets with a long bearing surface need more cuts than shorter bullets to keep pressure down.

Assuming similar bullet construction, bearing surface also really doesn't change pressure. When Wagner's Flatline nonsense came out, I tested their nonsense "signs" claims and sent them the Traces. Bearing surface can matter, but that's for nonstandard construction.
Otherwise it's only "important" when people are attempting to make a basic estimate square with reality, when they won't actually do any testing to confirm reality.

 

[Tidesloe]

I've had wild pressure swings using n550 in a 300SS. A buddy of mine had near disastrous pressure swings with n550 in a 338 SS. I have 13 lbs of it that I won't use now, because of it. This doesn't mean it won't be more stable in another cartridge, but the SS line it's very unstable. To the OP, it may still be worth trying in the 270 based 300 Sherman, but be aware of the potential, and be careful with it until you know what it's gonna do in your application.

 

[Veteran]

My post wasn't dismissive, unless you won't jet fo of some bizarre hero worshipping. It was explanatory, to your original question, about why reality and QL didn't match.

QL is a kid with Ice cream on his face, because very few who use it, don't understand what it actually is. How many people have told you false information? "Uhhh... Change start pressure.....uhhh, change twist rates...".

Powder burning rates change with pressure and volume. "A" simulation based off fixed values is moronic, if you want to actually know what's happening; which per the point of the thread, you did. If you want to guess a start charge, without paying $300. To then attempt to justify why you paid someone else to make a guess, then compare volume and expansion rates. Volume to bore is how it's been done, and why the Creedmoor and 30-06 take extremely similar powders(not progressive).




Assuming similar bullet construction, bearing surface also really doesn't change pressure. When Wagner's Flatline nonsense came out, I tested their nonsense "signs" claims and sent them the Traces. Bearing surface can matter, but that's for nonstandard construction.
Otherwise it's only "important" when people are attempting to make a basic estimate square with reality, when they won't actually do any testing to confirm reality.

Fyi.....Ba is only the starting burn rate value in the burn rate curve that QL uses. It is not a constant. Pressure, Temperature, and burn rate vary throughout the explosion in QL. " A program based on fixed values" would yes be moronic to quote you.

Please be sure you actually know anything about QL before becoming an expert online......